The Preparation of Methylene Cyclobutane and Methyl Δ' Cyclobutane Citation Fischer, James Rodney (1941) The Preparation of Methylene Cyclobutane and Methyl Δ' Cyclobutane. Master's thesis, California Institute of Technology. doi:10.7907/mdp4-fq82. https://resolver.caltech.edu/CaltechTHESIS:02102025-210337743 Abstract No abstract. Item Type: Thesis (Master's thesis) Subject Keywords: (Chemistry) Degree Grantor: California Institute of Technology Division: Chemistry and Chemical Engineering Major Option: Chemistry Thesis Availability: Public (worldwide access) Research Advisor(s): Buchman, Edwin Raphael Thesis Committee: Unknown, Unknown Defense Date: 1 January 1941 Record Number: CaltechTHESIS:02102025-210337743 Persistent URL: https://resolver.caltech.edu/CaltechTHESIS:02102025-210337743 DOI: 10.7907/mdp4-fq82 Default Usage Policy: No commercial reproduction, distribution, display or performance rights in this work are provided. ID Code: 16991 Collection: CaltechTHESIS Deposited By: Benjamin Perez Deposited On: 11 Feb 2025 16:54 Last Modified: 11 Feb 2025 17:16 Thesis Files PDF - Final Version See Usage Policy. 19MB Repository Staff Only: item control page

'l'HE PREPARATION OF METHYLENE CYCLOBU TAi"'JE AND METHYL A I CYCL OBUTENE APPENDIX: 1 rHE PREPARATI Ol'J OF CERTAIN CYCLOBU'l'ANE DERIVATIVES; ETHYL CYCLOBU'rANE 1,1-DICARBOXYLATE, CYCLOBUTANE 1,1-DICAFBOXl'LIC ACID, CYCLOBUTANE ViONOCARBOXYLIC ACID, CYCLOBUTANE MONOCARBOXYLIC ACID CHLORIDE, CYCLOBUTANE I·i ONOCARBOXYLIC ACID AMIDE. Thesis by J. Rodney Fischer In Partial Fulfillment of the Requirements for the Degree of Master of Science • California Institute of Technology Pasadena, California 1941 Table of Contents Page Theoretical Discussion 1 Ex pe ri men t al Secti on 9 Plot I 13a Plot II 14a Plot III 20a Plot IV 21a Plot V 21c Ref er enc es 32 Ap pendix 33 Summary 34 Ex perimental Secti on 36 Ref e rences 46 1 THE PREPARA'.I1I ON OF i:rE 'r HYLENE CYCLOBUt ANE AND EETHYL A I CYCLOBUTEi JE Hany attempts to synthesize cyclobutadiene have been made without success. In this laboratory, a broad research prog ram, under t he direction of Dr. Edwin R. Buchman, is being conducted on the cyclobutadiene pr oblem. One phase of this program is the attempt to synthesize cyclobutadiene by the following series of reactions: CH 2_ I Na CH 2- c-coocoH 5 --.... cooc""H I :a s CH 2 ~ CH- CH-COOH I Heat 2 I CH -CH 2 CH 2 - PCla ) 8 CH-COCl I I CH --CH 2 NaOBr 2 ® CH 2 - CH- NH 2 I I ) CHs--CH 2 (J) @ CH 2--CH-N (CH 3 ) OH 3 I I CHa- CH Heat -2 CH 2--CH I I CH2--CH ® ) 2 OAc CH 2--C H II CH I CH~ OH I - Se Oa Ace ti 9 > Anhydride @) OH- ) 2 @ CH- CH I I CH- -C H L_t CH-CH 2 @ cs Na 1 CH--{! H 2 I > H2 0 I I CH - - CH ONa Na I CH-C H cs 2 ) I II CHJI CHr-C H 2 @ ) © OCS 2 CH 3 1 CH-CH I II CH-CH Heat II II CH2-CH CH-CH @ @) The various ste ps in the preparation of cyclobutane carboxamide (5) are describe d in the a ppendix. Due to the l aborious procedure, resulting small yield, and exp ense i nv olv e d in the preparation of cyclobutene (9), a suitable, more easily acquired, model compound , wa s sought, u pon which all the pr eliminary experiments could be c a r r i e d out. Me thyl J:,. 1 cyclobutene was first prepa r ed by Gustavson 1 who treat ed pentaerythrityl tetrabromi de with zinc dust and ob tained a hydrocarbon analysing for C6 H8 , to which he assigned structure (I) below. This compound -when t r eat ed with HI in acetic acid yielded an iodide from which HI could be removed with KOH yielding a different hy drocarbon 3 also analysing for C5 H6 to which Gustavson assigned structure (II) below. These •isome ric hydrocarbons he named (I V • . ,, and (/ Ethylidenetrime t hyleneIf respectiny 1 t rimethylene ively. CH 2 I 'c CH-CH 3 CH/' 2 I III II CH2 C-CH 3 CH 2 CH I ll V Idzkowska and Wa -iZ. n e r 2 , showed that Gustavson's Vinyltrimethylene was a mixture of methylene cyclobutane (III) and some cyclopentane. Later Fecht 5 proposed a structure consisting of two cyclo propane ring s having one carbon in common, i.e., spiro bicycle pentane IV. Zelinsky and co- workers 4 , prepared a hydrocarbon from 1,1-di(bromomethyl) cyclopropane and zinc dust that had physical properties identical with those of Gustavsons Vinyltrimethylene, and thus apparently added ex perimental evidence to Fecht's hypothesis. Philipow 5 carefully fr a ctionated the hydrocarbon mixtu r e obtai ned by the action of zinc dust u pon pentraerythrityl tetrabromide and obtained two compounds, one boiling at 41.5-42° and the other 37.5°. To the hi gher boiling he assi gned the methylene cyclobutane structure (III); to the lower boiling , (V), methyl ~'cyclobutene. His conclus- ions were based on careful oxidative studies of both 4 compounds. Furthermore, catalytic reduction of the mixture yielded pure methyl cyclobutane. Demjanow and Dojarenko 6 were able to prove conclusively that the major constituent of Gustavson,s llvinyltrimethylenJwas methylene cyclobutane. This was accomplished by comparing, by means of a solid derivative, material obtained from pentaerythrityl bromide with methylene cyclobutane independently synthesized by a method indicative of structure. Ingold 7 carried out oxidative studies upon the hydrocarbon prepared from 1,1-di(bromomethyl) cyclopropane and zinc dust and concluded that the substance was essentially methyl,A 1 cyclobutene, with the possibility of methylene cyclobutane being present also. The procedure described by Philipow 6 , fractionation of the hydrocarbon mixture obtained from pentaerythrityl tetrabromide and zinc dust, was followed in the first attempt to prepare the model compound, methyl A'cyclobutene. A total of 1340 grams of crude hydrocarbon mixture was fractionated. The column used was 6 1/2 feet long with inside diameter of 22 mm, packed with glass helic/~s and fitted with total reflux, variable take-off head. The first fractionation yielded 234 g. of distillate boiling in the range 30-4o 0 /750mm, (equals 18.3% of total), and 1042 g distillate boiling range 4o-41.7°/75omm, (equals 81.7% of total). (See Plot 1). It was found in this in- vestigation that pure methylene cyclobutane boils at 5 1 41.39°/750mm corrected, and methyl Ll c yclobutene at 37.10°/750mm corrected. A second fractionation through the same column seemed to give little further separation, the two distilling ranges being in ratio 16% to 84% . No def- inite break in the curve near the boiling point of methyl .A 1cyclubutene was observed. (See plot 2). While the research was in progress, a paper by Rogowski 8 appeared, claiming that the hydrocarbon prepared from pentaerythri tyl tetrabromide was really spiro bicyclo pentane . The proof of structure was based on an e lectron diffraction study. This made it desir~ble to pre pare re- ' asonably pure samples of both methyl L1 c yclobutene and methylene cyclobutane f~~- electron diffraction study in this laboratory. A portion of the methylene cyclabutane boiling at 41.2-41.3°/745mm from the second fractionation of the crude hydrocarbon mixture (Plot 2) was given a third fractionation through a 3 ft. column and a constant boiling middle portion of the distillate was used for the e l ectron diffraction pictures. Physical pr operti es of methylene cyclobutane: Boiling point 41.39°/750mm (c orr.); D420 ~ 0.7401 . A preliminary examination of the material by Schomaker an d Shand 9 yielded a max . and min. curve quite dissimilar to that of Rogo wski 8 , but reasonably near the cur~e to be expected from methylene cyclobutan e. 'l'he conversion of methylene cyclobutane into methyl cyclobutene was then investigated. Gustavsonl treated 6 methylene cy clobutane with HI forming the tertiary iodi de. The iodide was then treated with alocholic LOH yi e lding a II I diffe r ent hydrocarbon, presumably me thyl L'.l cyclo13'tene. In this res e arch, methylene cyclobutane was treated with HCl, HBr and HI, forming the tertiary halide in each case. HX was then split out with KOH yi elding a mixture of hydrocarbons. From the refractive indices and densiti e s of the two C6 H8 hydrocarbons as found in this paper the ratio of methylene cyclobutan e to me thyl J1 I cyclobutene was calculated. CH:;r-C KOH A.nd I /C H3 II CH~CH 37% CH~C/ and KOH I CH ;;i II CH--C H 2 37% KOH and ) 32% 68% Dojarenk o 10 reports that methylene cyclobutane when passed over alumina at tem peratures ranging from 300° to 4oo 0 c yields some me thyl A' cyclobut ene along with by-products resulting from dehydrogenation, polymerization and hydrogenation. Several experiments were conducted, in which me thyl ene 7 cyclobutane was passed ov e r activated alumina, but in all cases, a very small amount, i f' any, of me t hy l .4 1 cyclobutene was for-med. Unchan ge d me thylene cyclobu tane, lo w boiling bydrocarbons and hi gh boiling polymer s we re found. Attempts were made to dehydrate 1-methyl cyclobu.tanol-1, prepared by absorbing methylene cyclobutane in 66% sulfuric acid 1 1 • Heating th e t ertiary alcohol with sulfuric acid, anhydro u s oxalic acidi 2 , or with traces of iodine~ 3 did not yield me thyl ,6 1 cyclobutene. The alcohol darkened an d polymerized when heat e d with sul fu ric acid or oxalic acid but failed to react at all with iodine at atmospheric pressure, the unchang ed alcohol being recovered. The procedure finally used for the prepara tion of methyl __t'.j 1cyclobuten e was essentially that of GustavsonJ.. l-iodo-1-methyl cyclobutane was prepared from me thylene cyclobutene and HI and reacted with KOH in ethyl cellosolve (ethylene glycol mono ethyl ether ) yi elding a mixture of hyd roc a rbons from which methyl A'cyclobutene was se parate d by re peated fractionation. (See Plots 3, 4, 5, ical properties of me thyl ~ 1cyclobutene; . ). Phys- Boiling point 37.10°/750mm (corr); n; = 0.7188. 5 These figures agree only mode rately well with t he pr ev iously report e d data 2 ' 5 on this compound. Gustavsonz prepared this hydrocarbon in the same manner and found B.P. 37.5°/750mm; N~8 D. = 1.40255. d~ = 0.7235; d! 8 = 0.7052; Philipow 5 claime d to have obtained this compound by fractionation of the hydrocarbon mixture 8 resulting from the action of zinc on pentaerythrityl bromide. His constants agree with Gustavson's only moderately well. B.P. 37-39°; of the poor agreement, it is felt that our constants are more nearly correct since highly refined fractionation techniques were employed which were not available to the previous investigators. A preliminary electron diffraction study of t h is material has also been made by Schomaker and Shand 9 and the pictures obtained here again do not correspond to those reported by Rogowski 8 • Selenium dioxide has been used for the oxidation of unsaturated aliphatic and cyclic compounds. Some rules have been established as to the ease of oxidation of certain structures. A very extensive review has been published re- cently by Guillemonat~ 4 • He found that oxidation occurs primarily at the carbon atom alpha to the tertiary ethylenic carbon atom. If dissimilar groups are attached to the ethylenic carbon atom the ease of _oxidation is in the following order: CH 2 ) CH 3 > have prepared ✓.1 '' cyclopentenol 2 CH. Thus Dane and co-workersl. 6 from cyclopentene, and 2-methyl ~/'' cyclopentenol from methyl A' cyclopentene. Methylene cyclobutane therefore would be expected to yield methylene cyclobutanol-2. Using selenium dioxide in acetic anhydride solution, methylene cyclobutane readily reacted, resulting after hydrolysis, in a very high boiling liquid containing selenium but no active hydrogen as determined by the zerevitinow method. ther investigated. This compound has not been fur- 9 EXPERIMENTAL SECTION Pentaer_ythritol; 8 CH 2 0 2CH 3 CHO + Ca(OH) 2 + 44 30 800 g = 26.7 mols ~ 2C ( CH 2 0H ) 4 74 210 g = 4.77 + Ca(HC00) 2 136 130 3.22 mols Yield: 377 g melting range 247-249° (corr) equals 58% theory. Procedure: The procedure outlined in Organic Synthesis~ 6 was followed. In a twelve liter round bottom flask, 800 g of para-formaldehyde was dispersed in five liters of water. 210 g of freshly prepared acetaldehyde (paraldehyde distilled with trace of sulfuric acid) was added followed by 190 g of calcium oxide added portionwise ov e r a period of one hour with vigorous stirring. ture rises to 50-55°. Temperature of reaction mix- After all the Cao vms in, the sol- ution was stirred and tem pe rature held at 50° for three hours. The solution was then cooled, filtered using suction, acidified, and treated with 100 g of Norite and filtered. The solution, still somewhat colored, was evaporated on a hot wate r bath at 100 mm pressure, filt er ed warm and allowed to crystallize. 1st cro p of crystals 184 g. M.R. 230-235° uncorrected. 2nd cro p of crystals 226 g. I•!I . R . 220-225° uncor·recte d. 3rd crop of crystals 4lt- g. M.R. 205-210° uncorrected. 4th crop of crystals 17 g. IVI . R. 21 0-215° uncorrected . This material was recrystallized from the minimum amount of water containing 10 cc of HCl. corre cted. Yield, 377 g. M.R. 247-249° 10 fentaerythrityl Tetrabromide: 3C ( CH 2 OH )4 + 4PBr3 136 3C(CH 2 Br) 4 271 680 g = 5 mols 4H 3 P0 3 + 388 2,600 g = 9.6 mols Xield: 1796 g of crude tetrabromide or 92% of the ory. Procedure: The procedure outlined in Organic SynthesisJ. 7 was adapted to larger quantiti e s. Apparatus consisted. of a three liter three necked ground g lass flask fitted with two 21~/40 side arms and a 45/50 g round g lass center opening . One side arm carried a 500 ml. g round glass dr·opping funnel, the other was loosely stoppered. The center open- ing carried a condenser, the outlet of which was connected throu gh a calcium chloride guard tube to an HBr absorbing system. ~ 680 g equals 5 mols pentaerythritol 1 M.P. 252° corr. was placed in the flask and 2600 g equals 9.6 mols of PBr 3 was adde d in portions over a period of four hours while he ating on a steam bath. After all t he phosphorus tribromide was in, an oil bath was substituted and the # tem pe rature rais e d g radually 2 • to 170° an d held there for 20 hours. The mi xture was allo we d to cool, scraped from the flask into a large volume of water, agitated, decanted and a gain washed. The material wa s then collecte d on a filter, washe d with 1 lite r of 95% ethanol an d allowed to --------------------------------------------------------~J.In part pr e pare d as des cribed in this pape r, remainde r purchas ed from Lemke Co. t 2 It is n e c e s sar y to r a i s e the t em9erature g r a dually s i n ce phos phorus comp ounds whic h s pon tane ously i g nite a re r el eas e d i f mi x ture is strong l y he ated. 11 to air d ry. Yi eld, 1796 g of raw tetrabromi d e. Some of this crude ma teri a l was e xtra ct ed in a Soxhl e t e xtractor using 95 % ethanol and then r e crystallize d from acetone a lcohol. Mel ti ng r an ge 157-158 ° unc orre cte d. In this manne r 478 0 g (35 mols) of pe nt ae r y t hritol plus 19,000 g (70 mols) of phosph orus tri b r om i de yi e l de d 12, 0 24 g ( ...,1 J mo 1 s ) 01"" t e t r a ,or·onn• o.e " f or an av e r age yi• e 1 a- 01"" of . 0" 8 • 5 ;o Hydrocarbon 1Hx ture: C(C H2 Br) 4 + 2Zn H2 0 1 liter Et OH 5 OOc c ) 388 65.4 776 g = 2 mols 785 g = 12 mols CsH 8 68 + 2ZnBr t.. Xield: 115 g of crude hyd rocarbons or 84.5% of theory. Procedure: The a pparatus consisted of a 12 liter flask fitted with a thre e nec ked adapte r carryi ng a dropping funnel, mercury s eal ed stirre r, and a 38cm column without packi ng , fitt ed wit h a cold fi nge r at the top and h aving t he outl e t a ttache d to an ice wa ter cool e d . condenser. The rec e iver wa s surround ed by i ce . . 776 g (2 mols) of ♦ pentaeryth ri tyl t e trabromi d e:i. was crushed in a mortar a nd mi x ed intimate l y with 785 g (12 mols) of zinc du st. On e lit e r of water wa s th en c autiousl y a dded . (Note.-At ti me s the r eaction bec ame v e ry vi g orous when wa t e r WAS added; in one i n sta nce th e mixture caught fire). The mixture was t hen he ate d to 85° on a wat e r bat h with ------------------------------------------------------•irn part su ppli e d by Alf Reims. 12 stirring. 500 ml. of e t hano l was then a dded portionwise from the dropping funnel ov e r a period of two hours, or until no more hydrocarbon appeared to come over. Towards th e end of the reaction the tem pe rature was raised to 95° forcing the last tra ces of hydrocarbon over a long with some a lco h ol and water. The mixture frothe d considerably during the re ac tion and was controlled by r a isi n5 an d lo wering the stirrer. The distillate was washe d with t wo 100 ml portions of ice water and then dried over calcium chloride at o0 • The wash water was added to the next run. dry hydrocarbon mixture weighed 115 g. Crude In this manner 11,745 g (30.3 mols) of tetrabromide plus 11, 8 79 g (182 mols) of zinc dust yielded 1425 g (21 mols) of hydrocarbon for an average yield of 69%• This included one run that was almost completely lost due to fire and several others where material was lost due to careless handling. yields vary between 70 and 90%. Nor·mal The crude hydrocarbon mixture was fractionated using a column 6 1/2 f ee t long with an inside diameter of 22 mm. The column was packed with helices, insulated with asbestos cord with resistance wire wound between the turns for ext ernal he ating; total reflux, variable take off ty pe with ground glass conne ctions. 13 ~irst Fractionation Hydrocarbon Mixtu re . Boi li n g rang e at 750mm. (See Plot 1) Weight of Fraction ~ We i g h t 6.6 g 6 .6 g 30-31° 17.1 23 .7 31-32° 19. 8 43.5 32-33° 21.5 65.0 33-34° 13. 6 78 .6 34-35° 28.7 107 .3 35 -36° 19.1 126.4 36-37° 18 . 8 11.i-5 . 2 37-38° 22.6 167.8 38-39° 29 . 0 196.8 39-40° 37. 2 234. o 40-41° 167.0 401. 0 41 -41.7° 875 .0 1276 . o To 30° First Fractionation of Hydrocarbon Mixture from Tetrabromide . - ~ - -· • t-• • · t- • .. - .- -· ...... ·-·-- ::·r_;::: r-~~=- 1~!_:::--::!~ :-~ :-~=~~-~-= r·: ;·•· ' ' T' :t : :r. :L ~ ;r." : :::. ~. b. _:_::_ ·· •• ··. ..1···. . . ::~-: -==·_ ·-::::- --·. I -- -- - --·· · - - - .. - . . .. 1---. - -• -·. :....::_:_ -- ---· • •• • ,, .u. ~ .::t- ' ~ ~ ~ ~ N\ "' ~ "-\ ~ ~ . · ·• - - ·-·- --· - - --•- · - ,, ~ ~ ,.., •N ..... ' <) ""I N\ 14 Second Fractionation Hydrocarbon Mixture. Boiling range at 750mm Vfeight Fraction (See Plot 2) L.Weight To 30° 18.0 g 18.0 g 30-31° 32.5 50.5 31-32° 30.5 81.0 32-33° 18.0 99.0 33-34° 17.0 116.0 34-35° 12.5 128.5 35-36° 10.0 138 .5 36-37° 13.5 152.0 37-38° 12.5 164.5 38-39° 11.0 175.5 39-40° 17.5 193.0 40-41° 43.0 236.0 41-41.7° 974.o 1210.0 14a Second Fra ction a tio n of Hy dro carb on Mi x tu re fro m Tet r a b romide. F: ~~-rn-1 ~f ~TT.....,.- :;. n-r -r- -,-- r- t'->- i- f-.-r-- ~ ~ ;.-; ...,...r .. •r r r~rr t"TT"1'- -,-ffi ··-· .... , • · • •· ~ - ·' •·--· - •·• • .:.:..:: r::-:-:: ·- -- .--. -.....-· ----·............ -·-• -- ;.... - · •t---- · ••• --- -:-:-:·:· .::--:.= ~ ::..: .:::-::. ___-__ ·- -- --·-- .::: .. .. . -.. •-- - -- ,..._ . • • ...... • :-:::-+ - · ·•· --- ·_· - -- - -- - ----1---- - - .. . --- -- • •· • . • •- • •· t- • - ·• . ~ - - - - -·- -- ----- - ---- --- · • · • -• .• - - • •· :.. _ _ : _ ___ ... ------ • • - · i-- - - -- .. i> ,. : it· ,_ V) • -: : : :: : I : :.:-~ . - - - - - -- - ·- I ,. . i .. II . . ,_ ~ ... ~ 0 Q) . . .. 1: ... l I· I '- ~ .j: . :: :· II - i. I I !· I. \) f-.. I .. I- ~ I· t,,. ~ -.j ·""1-- ..... vi ~ ll.... 0 ,. I I ,--------·-... -·-- . ----- •-- - - i.- - - t - - - • , . .. · - • -- • -•· ·• • • •-r---- r -· ••• ..-... - · • ---• -- -: -· • · .:.:__ • ·•·- · I . --• --· - · --- :._:-_;_:-- ·----~--- __.._ - -· 15 J:b,ysical Properties of Se cond Fractionation Fractions. Boiling range 750mm Weight Refra ctive Index . N.1.a D To 30° 18.0 g 1.3798 g 30-31° 32.5 1. 3810 31-32° 30.5 1.3832 32-33° 18 .0 1.3869 33-34° 17.0 1. 3905 34-35° 12.5 1. 3930 35-36° 10.0 1.3968 36-37° 13. 5 1 .4000 37-38° 12.5 1.4049 38-39° 11.0 1 .4084 39-40° 17.5 1.4139 40-41° 4 3.0 1.4180 41-41. 70 974.o 1.4218 Third Fractionation Hydrocarbon Mixture for Electron Diffraction Sa~ple: A small amount of material boiling 41.2-41.3°/745rnm was fractionated through a 3 ft. column paclrnd with helices and the middle portion of distillate was given to Schomaker and Shand for el e ctron diffraction study. ...... 2.5 g . 41.39°/75 omm .... .. 7.0 g . 41.39-41.54°/750mm ...... 2. 0 g . 41.24-41.39°/75omm Corrected 16 Physical Properties of Methylene Cyclobutane Fractionated from Hydrocarbon Mixtu~. Boiling point at 750mm Nl.O D. 41.39° corrected. = 1.4266; NJ l.S -- 1 4220. j, • D ' l-Chloro-1-Me th;yl Cyclobutane. CH2 -C I /CH~ I --CH CH 2 CH--C + I HCl 2 /CH 3 I"c1 C2H - CH 2 2 68 104.5 1 7 g = O • 25 mol Xield! 21 g B.R. 90-91°/745mm equals 80%. f!'.Q,Qedure: 75 g of concentrated HCl, d. 1.19, was placed in a 250 ml. glass stoppered bottle and cooled to o0 • 17 g (0.25 .mols) methylene cyclobutane N18 = 1.4218 previously cooled to o 0 D was added and carefully mixed with the HCl. After most of the reaction was over (5 min.) the bottle was placed in a mechanical shake r and agitated for one hour. The tertiary chloride was then separated from the heavier aqueous phase, washed with sodium carbonate solution, then with water and put over calcium chloride to dry. 25.5 g crude chloride. Weight The second fractionation through a 40 cm column gave the following.85-90°/745 ........ 1.2 g . 1'rl a 5 D 90-91°/745 ........ 21.0 g. N 25 D -- 1 • 4275 • = 1.4288; ND .= 1.4311; 20 d! 5 = 0.9444; d! 0 = 0.9495. 17 l-Bromo-1-Methyl Cyclobutane. _..........CH;; CHl;j--C........._ + 68 HBr I ) CH - CH 2 2 81 34 g = 0.5 mol I Br 149 130 g = 1.6 mols Yield: 54 g B.R. 55-57°/lOOmm equals 72.5%. Procedure: 150 g 48% HBr was saturated at o0 with HBr making a 62% HB r solution. To the acid cooled to o0 was added 34 g (0.5 mol) me thyl ene cyclobutane Nie= 1.4218 D also cooled to o 0 and the two g ently mixed by hand for about 10 minutes then put on a mechanical shaker for one hour. The t ertiary bromide was separate d from the aqueous phase, washed with so dium carbonate solution and water and then dri e d over calcium chloride. Weight, 71 g of c r ude bromide. The second fractionation throu gh a 40 cm column gave the foll oviing. - . . . . . . . few drops 55-57°/lOOmm . . . . . . . 54 g . N85 = 1.4673; D 53-55°/lOOmm d 425 ::: 1 • 3110•' N20 = 1.4698 . D . d: .0 .. -- 1.3179. 57-118°/lOOmm .....• 9 g. l=.Iodo-1-1'.T ethyl_f..yclobutane. , -1 ,;, CR- - C ~Cr.~ 200g 1-"2 I HI AcOH + CH~ CH 2 68 63 g = 1 mol 128 154 g = 1.2 mols. CH2 ➔ I C_..........CH3 I'---I CH 2--C H 2 192 18 Xleld: 150 g B.R. 4o-42°/2omm equals 76.5%. Procedure: The HI was prepared from I 2 and t e trahydronaphthalene (tetralin). The iodine was added portionwise to the boiling tetralin by a ll owing the refluxing tetralin to tric kl e through solid iodine on the way back to the boiling flask. By controlling the amount of tetralin pas- sing through the iodin e the HI was generated smoothly and its rate of evolution easi ly controlled. The HI from the generator was passed over some moist red phosphorus then t h rough phosphorus pentoxide and finally into glacial acetic acid cooled in ice water. By this procedure about 85% of t h e I 2 is converted into HI. 15L~ g (1. 2 mols) of HI was abs orb ed in 200 g gl ac ial acetic acid at o 0 • 68 g (1 mol) of me t hylene cyclobutane Nt 8 = 1.4218 cooled to o 0 was added to the cold HI solution in a glass stoppe red bottle. After tying the stop- pe r in, the bo ttle was carefully shaken until the main reaction was over, then placed on t he mechanical shaker for half an hour. The reaction mixture was poured into one lit e r of water followed by separation of the two phase s. The heavy iodide was freed of 1 2 and HI by s hak- ing with 1 f. s odium hydro gen sulfite, 1 f. sodium carbonate and finally with two washes of dis till ed water. Iodide was dried over calcium chloride, the crude ma terial weighing 184 g. This material was then fractionated. The iodide was colorless when freshly di still ed but colored 19 to 4o 0 /2omm .... ..... 6 g • 4o-42°/2omm ......... 150 g. upon standing. Using the above procedure , 423 g (6.22 mols) of methylene cyclobutane was treated with 891 g (6 .95 mols) of HI yielding 1143 g of crude iodide (5.84 mols) equals 94% theory. d ~_thyl L) 1 C;y:~bu tene. CH2-- C_.-CH3 I I' I + KOH 250cc Cellosolve 68 - 98 g = .5 mol 56 g = 1 mol Xield: 20.4 g of crude material equals 60%. Procedure: The following procedure was worked out using tertiary amyl chloridei 8 as a model compound. Ethyl cello- solve (ethylene glycol monoethyl ether) as solvent gave hi gher yields than ethanol or ethanol and wateri 8 , apparently because of its hi g her boiling point. Diethylene glycol was tried but the chloride remained as an immiscible phase• Higher boiling cellosolves such as butyl cellosolve gave about the same yield as ethyl cellosolve. 56 g (1 mol) of KOH was dissolved in 250 ml. cellosolve on the shaker (1/2 hour). Thi s s olution was heated to refluxing in a 500 ml. g round glass flask fitted with droppin g funnel and with a reflu x condenser as a column. ~ater in the reflux condenser was ke pt at 45°c. The out- let at the top of the reflu x condenser lead to another condenser containing ice water an d then i n to a receiv e r 20 c ool ed in a d r y ice b a t h . 98 g (0 .5 mo l) of c r u de t e r- ti ary io d i de wa s a dded d r opw i se ov e r a pe ri od o f t wo hours to the reflu x i n g collo so lv e . The r aw hydr ocar b on mi x ture obtai ne d wa s was hed with ice water a nd d ri e d ove r magn e sium pe r c h lorate. way a total We i ght , 20 . 4 g N ~~ = 1 .4080 . In this o f 1 143 g (5 . 85 mol s) o f t e rtiary iodide yi e lded 223 g (3.29 mol s) o f h ydroc a rbon equal to 56% o f the ory. The c r u d e hydrocarb on mixtu re wa s t hen fr a ctiona t e d . 'r h e 6 1/2 ft. column d e scribe d p re ,vi ou s l y ( p. ll-) wa s us e d for the first f r a cU. on ati on . Becaus e of t he s mal l amount of mate ri a l , a still - b as e wa s used . Th e stil l - ba se con- sis t e d of satur a t e d a li phat i c h ydr ocarb on s boi l ing in the range 60 - 61°/746mm and wa s p re par~d by fr a c tiona tion of 6 0-7 0 ° li g roin . F i r st Fr ac tionation o f Hyd rocarbon Mixt u r e from Te rtiarJ'.:_ Iodi de. (See Plot 3) We i g ht Fr a ction Weig ht 32-36° 12 g 12 g 36-37 ° 1 6.7 28 .7 37-38 ° 61 . 0 8 9. 7 38 - 39 ° 44-. o 133.7 39-40° 23 . 5 157 . ;2 40- 4 1 ° 13.7 170.9 41-42 19 . 0 189 . 9 42-47° 10.0 199 . 9 Boiling r an ge 745mm 20a First Fr a c t :io nation of Hydroca rbon Mixture fro m Terti a ry Iodide. · - - -- - • -----t-- - ·-· - --- 1.--...--- ~- ---· ·-·- ·- -· : ~ :: _c:-:-: __-· : : :l ): : - ·:: : '\ : • \.: • ::, - II\.\ 0 ~ 11'1 ~ ~ ~ \!I ~ . : . :1: ,.. \) j 0 ~ 0 ~ ..... -l • I- l ·-.... - Yl I Q i ! i ., i . .. .. I " C 0 CD --·-· ..... ·-• - ·- ·- - ·-· ·. - ---· ·• ~ ~ - • :\ ·:f .... - --- ----. -·- ----.--------- • ' - -- ·· - • ·• - •- • · · •· -•·- - •- - \) - - ~ - 1--- - ·--·--· - ·- ---- -- ··: -• - - · \ :ti .. . ~ ·:\ : ·:, \ -. .•r~--· ··-•-· ...... ..:t- 0 . . -- . - --- -•- - ---------- --- •• .L----- . - - . . ........ - ------- ----- - -- -- ·=---- ~ 21 .Sec o:1 d FractiQDat,ion of Hydrocarbon :oxtu~from ~rtiar,¥ i.Q.dide (See Fi g . 4) Only material boiling above 36°/745mm was refraction- ated .using the same 6 1/2 ft. column. Boiling range 745mm Weig ht Fraction Weight 36.0-37.0° 22 ·g 22 37.0-37.5° 27.8 49.8 37.5-38 .2° 26.8 76.6 38.2-39.1° 18.5 95.1 39.1-40.0° 19.0 114.1 40.0-41.0° 22.0 136 .1 41.0-42.0° 13.0 149.1 42.0-45.0° 6.o 155.1 For further fractionation the 6 1/2 ft. column was too large; instead, a spinning band column similar to the one described by Bake:r.f1ms used. This column had the equivalent of 18 theore tical plates at the reflux rate and through put used. 2la Second Fra ctiona tion of Hydrocarbon Mi xture from Tert. Iodide. tt+ tP·r ·i-~-r-. -h '""!rt· t1 n - · - · •• • - ·- · ••• · 1 • --- - , -♦-• ·- · · - . . ... . ___.,._. . .. . . .. - ·- • ·. . . ..... . J :.·:: .. t--+--+--+---1--+~+--+---11--+--+-~-+---ll--+--+--+---l--+--+--+---l--+--+-+---I--+-:-;-__:_+----- +-·--·---1 ~ ~ Ii:) ~ _, , .. :....'\ :. .. ··1····: ' I I " I : ::T · ·· \. I ! i I i ~ lb ~ ~ ..... I I I I , I l u ...-.l st: T :~ - i ~ ....... 1--- . . .. I ' ~ ::.: j:. ·· ::1 . t-------+---+----+--t---+-- - - t-"~ - - --+--t----+--+--+-------lt---·-+--t---+----!--+-+__,_- ----+-----+-- r !----+--+----+----,.i l i V) ~ C) ...... - 1-- "'l ~ I- I ~ \b c:) ~ --·-1..-. . l .. . I I i •\ .. \ .. •• :\ ·· • ·\: ·::\ ... . : : : : \ : .: --- .· ·. .. . . -- - ·- .··. ____ . .__,- -· - - . •· • -- ·· --•• -• · -- -··- :•:~<= ~:: : ;~~Ml~~: ~:-;.~~-~~hti l~ J;-~ =~=-~~~:~ ::~:- )~~ -· ~ ~i~; ~=\~ ==~ ~ \~~= ;-~~f~ 0 -~; ~~¥~:Ji_!:~~ ·::~~t~~:~f-+1J~B=:stt=:~t±:;~~~~-~~-~~~~- ::~:-~-~ :~::~i=~:==-~-~::-: ~~ ~~ ==0 "i :~:: i:i~j::~~ ::-~~~~ ti!:l) ~~Hi:tl:ic;:•+:;:ri:rqgi::f:_;~ ~§:~~~~- i< -;_._::~~ ~~ =::::~~:-::~:·· 1 . "'tro, - -t+-- \.> ~ 21b Third Fractionation of Hydrocarb on Mixture from Terti a ry Iodide. (See Plot 5) Boiling rang e 748mm N;i.a D Wei ght Weight 35 -5-37 .0° 12.0g 12.0g 1.41 00 37.0-37.5° 22. 0 34.o 1.4091 37.50 9.0 43. 0 1.4110 37 -5-38 .0° 9.0 52.0 1.4118 38 .0-39.0° 6 .5 58 .5 1.4149 39.0-40.0° 8 .o 66.5 1.4170 40.0-41.0° 18.5 85.0 1.4190 41.0-42.0° 20.0 105 .o 1.4210 42.0-45.0° 4.o 109.0 1.4128 Th i rd li'r a cti o!'fat ion of Hyd roca r b on Mi xture f ro m Tert . Io d ide. •~ -cµ~ .tt'"..l- !:=-t;.- , f4----rt tT!T.,_ + ' , tSif -~~ t:: no q:~ ,\ : .. •• ... ·\· • \ :·: "\ · .. ~ : : l\. . .,I ·i:x "' ~ ' ' • I \!, i ~ \) 0 I l i I ~ "...... . -· .. ·-. - - • - ·I ...& · - · · - - -f------. i j: ---------··- · -- -- l ~ a... ") ---- i ~ ~ \ :_ ::\ : --,- - ~ l ~ I ' · · - - f--· - - · - :i · ~ j l - ---· - ~ . _·-· . - ...:..=::.::----·- .1 - -· . .. .. ·-· ---- -- -.. . . ·- · · · ••· • ·· · •- -- - i.---~ - • •• -- • • ---- t-------- · · •· •- -· · - ~ .--· .- -- ---- -- :._:.--:-.:-r::::- :--- r-:::_: -- - - -- -- •· · - r--•- f-- • .......... 1- -· ; ....0 -r+-ri ~ }- \) ~ ::: I: ::: L. - clot) 22 The material boiling at 3'7-~8°/748mm was put through the column again and divided into 5 ml. fractions. Fraction N:.1.a Boiling range 750mm D 1 33. 2-35 .9° 1.4051 2 35.9-36.1° 1.4086 3. 36 .1-36. 2° 36.2-36.6°' 1.4088 1.4085 5 35.9-36.3° 1 .4086 6 36.3° 1.4087 7 36.3° 1.4088 8 36.3-36.4° 1.4089 9 36.4-36.7° 1.4091 10 36.7-38.2° 1.4108 4 Column shut off.- Since there were s mall variations in pressure during the fractionation and also because t he column Tihen shut down was apparently not at equilibrium , refractive index was considered a better criterion than the boiling point. The 5 ml. fractions numbered 3, 6, 7, 8 were combined and considered to be the purest methyl b'c yc lobutene. Phys ical Properties of Met_h_y_l_ _C..._y_c_l_o_b_u_t-:-e_n__e_F_r_a_c_t_1_·_on_a_t_e_d_ f.!:.2,~__)Iydrocarbon Mixture Prepared fro m Tertia!:Y._lodide. Bo ilin§ point at 750mm, 37.10° (corr.). N18 D = 1.4088; d! 0 = 0 .7244 ; d! 5 = 0.7188 . 23 Comparison of Hydrocarbon ~\l ixtures Obtained f:com l- Chlo r o1-.~i ethyl Cyclobutane, l-Bromo-1-2,i ethyl Cyc lo butane, and l-Iodo-1-Methyl Cyc lobutane . The c h lo ride , bromide an d i odi de we re treated i den tically. Ap p roxi mately 1 00% excess KOH wa s d is so lv ed i n cellosolve and the hali d e added dro pwise to the boiling al k ali solution, t he evolved hydrocarbon being collected in a dry ice cooled receiver. Chloride Bromide Iodide Yield 60% Yield ) Yield In t h is i n v e sti g at ion t he follo wi ng phys ic a l pr operti es were f ound: methyl Methylene cyclobutane, N~ 8 J 1 c y clobutene, ND18 = 1.4088 ; = 1.4220; d! = 0.7369; d! 3 = 0.7210. 3 The re- fractive i nd ic es of t he t wo isome rs d if fe r b y 0 .0132; the densities b y 0.0159. Using t hes e v a lu e s and ass uming t he h yd roc arbon mi x t u r e contains only me thylene c yc lobutane and me thyl fl 1 cycl obu tene t he followine; proportions of each isomer in the ~ i x tures ob t a i ned from the halides can be calculated. :-Ia l i de Pro port ions fr om Ref ractive In d ·l ces :Propo rtions f rom de n s iti e s Averas e Ct.r-C~H2 "·2 I I CH2 CH 2 CH- ".,. . CHs Chloride 61% 39% 66% 3.l~% 63% 67% Bromide 55 45 70 30 63 67 Iodide 32 68 31 69 32 68 r 2 u[ ~CH2 .,.C H, R R CH2 GI-I 3 /2 ,, Crt 2 ~ l?, I ,,CH 3 R, Actufally, upon fractionatin g larger quantit i e s of the mixture prepared from the iodide, roughly 40% was fraction ated out as methyl /j 1 cyclobutene and 28% as me thylene cyclobutane. Attempted I somerizatio n of Ivietill[lene Cyclobutane. CH -C_.....CH s Al 2 0 3 I 7 I 2 l CH-CH 2 AQQ§:£§.tus: The ca tal y st chamber consisted of a pyrex tube 40 cm long with i n si de di ame ter of 3 cm. A t hermomete r well r eac h e d to the middle of t h e cat alyst. Hydrocarbon was vaporized by dropping into a 50 ml. flask heated in an oil bath to 50-60°, and carried through t he catalyst by a slow stream of dry CO 2 • Reaction products were collected in a dry ice trap. Procedure: The catalyst used was Baker's n Hydralo» activ at ed alumina. off. When heate d for the first ti me some water was g iven The apparatus containing the alumina at 300°c was then evacuated for 1/2 hour in order to remove last traces of water. 25 E~: 15 g of methylene cyclobutane Nl. 8 = 1.4218 was D va porized and passed over the a lumi na at 300-305°c over a period of 3 1/2 hours. After all the hydrocarbon had been pass ed thr ough , the a pparatus was swept out wi th CO 2 for 1 1/2 hours. The dry ice coole d receiver was t hen re- moved, an other receiver attached an d t he apparatus evacuated, forcing over sev e ral drops of high boiling polymer having a t e r pene like odor. Low boiling material 7.2 g Hi gh boiling polymer .6 g 9 = 1.4192 9 N ;i. = 1. 4722 • Nl. D D The low bo iling ma teri al was fractionat ed t hrough a 20 cm column. 29.6-33.0°/745mm . . . . . . . .3 g. l"l. 8_ 'n - 1.4169 NJ.a = D Nl.e= D N ie= D 33 . 0- 34-. 0° /745mm ....... 4. 3 g . 34.o-35.2°/745mm ....... .8 g . 35.2-41.5°/745mm ....... 3. 0 g . 1.4205 1.4214 1.4222 Run B: 17 g of me thyl ene cyclobutane N l. 8= 1.4218 was passed D over the catalyst at 300-308°C over a pe riod of 4 1/2 hours. Swe pt out apparatus for 1 hour with CO 2 , t hen replaced receiver and evacuated forcing ov er high boiling polymer. Low boiling material 13. 3 g . Hi gh bo ili ng material .5 g . Low boiling material was fr a ctionated thro ugh a 20 cm column. . ....... .3 g . 33-34o'/747mm . .. .. . . . . 5.1 g . 34-35°/747mm . . .. . . . .. 3.2 g . 35-36° /71+7mm .. . . . . . . . 1. 8 g . 36-37°/747mm . . . . . . . . . .8 g . 28 -33°/747mm . N.1. e_ D - 1.4210 N J.e= 1.4215 D 26 1-Methyl Cyclobutanol-1. The procedure described by Demjanowii was used. + 68 86 34 g = .5 mol. X~: 27.0 g B.R. 115-118°/748mm, equals 63%• Procedure: In a 1 liter three necked flask fitted with stirrer, dropping funnel and surrounded by ice salt bath, 132 g of H~S0 4 was added to 66 g ice, the mixture cooled to o0 and 34 g (0.5 mol) of methylene cyclobutane, N~8 = 1.4218 added over a period of 15 minutes. Mixture was then stirred at o0 for 1 hour, made alkaline with 5N NaOH keepin g the temperature below 20°, and then the sodium sulfate that had precipitated was filtered off, the solution being put on continuous ethe r extraction for 5 hours. The ether extract was dried with K2 C0 3 , the ether distilled off, followed by fractionation of the residue. 85-115° /747mm ••.•...... 2 g. ... ... ... 27 g • 118-119°/747mm . . . . . . ... 3 g. 115-118°/747mm The mate rial boiling at 115-118°/747mm had the following properties: to -6°. d:- 2 -- 0.8971•, 24 ND = 1 •4333•, melting range -3 The alcohol is soluble to the extent of 1 part in 6.5-7 parts of water at 25°. Miscible with ether. Phenyl urethane :M .P. 139.9° (corr.) crystallized out of isopropyl ether. 27 ,Attempted Dehydration of 1-Methyl Cyclobutanol-1 Using H2 S0 4 • 1-methyl cyclobutanol-1 was dropped into refluxing 60% sulfuric acid containing some diatomaceous earth. A dark insoluble phase, with terpene like odor separated out on top but no hydrocarbon was evolved. The experiment was repeated using 50% and 40% sulfuric acid with the same results. Attempted Dehydration of 1-Methyl Cyclobutano~ using (COOH)ld The procedure described in D.R.P., 66, 866~ 2 was tested out first on tertiary amyl alcohol. The oxalic acid used was dehydrated by heating in an oven for 15 hours at 90°. Neutralization equivalent theory 46.0. Found 45.8. The tertiary amyl alcohol was added dropwise to the anhydrous oxalic acid heated on a steam bath giving a 75% yield of trimethylethylene. The same procedure was followed using 1-methyl cyclobutanol-1 but no hydrocarbon was formed. The mixture dark- ened, resulting in a polymer similar to that obtained from the attempted sulfuric acid dehydration. A,~mpted Dehydration of 1-Methyl Cyclobutanol-1 Using 1 2 Hibbert• 3 has dehydrated tertiary amyl alcohol by heating at 100° with 1 2 • This same procedure was attempted with 1-methyl cyclobutanol-1. 6.7 g of the cyclic alcohol was refluxed with a small amount of lid for 23 hours. 5 .5 g unchanged alcohol was recovered and only a trace of hydrocarbon was formed. 28 Selenium Dioxide Oxidation of i\:Iet~l~ Cyclobutane. Preparation of Se0 2 : 100 g of powdered Se was placed in an evaporating dish and concentrated HN0 3 added, (Hood). 200 ml. acid was added until no more oxide s of nitrogen were evolved. 'rhe resulting yellow solution was evaporated on a steam bath; the crude dioxide then purified by sublimation from a dye pot on to a watb glass using a free flame. I\ Yield 133 g of Se0 8 equals 94%. Guillemonat~ 4 describes the oxidation of trimethylethylene with selenium dioxide in acetic anhydride solution. Before working with the cyclic hydrocarbon, the procedure was tried out on trimethylethylene prepared by dehydrating tertiary amyl alcohol with oxalic acid. 2-methyl-2-butanol-l was formed in accordance with Guillemonat's findings. Yield 3,2 g B.R. 134-135°/749mm; active hydrogen by Zerevitinow's method 1.3. Guillemonat~ 3 reports B.R. 136-138°; N;4 = 1.441. The attempt was then made to oxidize methylene cyclobu tane using the same procedure. 10 g ( 0. 1L~7 mol) of methylene cyclobutane NJ. 8 = 1.4218 plus 15 ml redistilled D acetic anhydride was placed in a 200 ml. three necked flask fitted vii th stirrer, reflux condenser and thermometer. 9 g of selenium dioxide (0. 081 mol) was added and the mixture heated on a steam bath with stirring for 1 3/4 hours. The temperature of the refluxing liquid rose from 48-65°. The reaction mixture was poured into water re- sulting in two phases. Oily phase (12 g) smelled of hydro- carbon, acetic acid and ester. This material was shaken 29 with 5N NaOH at room tempera ture, extracted with ether and the ether solution dried over K2C0 3 • Th e ether was distil- led off leaving a residue which was then distilled at reduced pressure. 125-142°/lmm •..... 3.4 g. N26 = 1.5125 142-147°/lmm ....... 4.0 g N 25 = D above 147° /lmrn . . . . . . few drops D l .5125 1,r; 6 = 1.5235 Attem pts to make the benzoate, 3, 5 dinitro benzoate and phenylhydrazid of the material boiling 142-147°/lmm failed. Active hydrogen determination by Zerevitinow method gave absolutely no methane although reaction with the MeMg I did take place. 3.2 g, N; 5 = 1.5125 of material boiling at 142-147°/lmm above was refluxed for 15 minutes with SN NaOH, extracted with ether, the ether solution dried and the ether distilled off. The residue was then dis- tilled. 120-140°/lmm ........ few drops, 140-145°/lmm ........ 2.0 g, N 2 3 = 1 • 5 388 . D N 23= D 1.5160. Both of these fractions were treated with MeMg I but no me thanewas evolved. Some of fraction 140-145°/lmm was heated on a spatula and left a residue of Se. From these results it was concluded that the expected com pound, me thylene cyclobutanol-2 was not obtained. Methylene Cyclobutane Di bromide. T82_ CH-Cd;H:a I 2 I Br~ -lQO CHs-CH 2 68 17 g = . 25 mol 160 44 g = . 27 mol ~ ~ :2Br 1 CH~CH 2 228 30 XltlQ: 54 g of crude, equals 95%• 35 g B . R . 84-85°/15mm equ als 61%. Procedure: 17 g (0.25 mol) methylene cyclobutane N 18 = 1.4218 D plus 44 g (0.27 mol) Br 2 a dded simultaneously with stirring into a 100 ml. three necked flask cooled to -10°. The bromide was kept in slight excess and experiment was carried o ut in subdued artificial li ght. Product was washed with 1 f. K 2 C0 3 and water and dried over CaC1 2 • N26 D = 1.5410. Vfeight 54 g, After second fractionation through a 20 cm column 70-84°/15mm ... .... 6.5 g . 84-85°/15mm ....... 35. 0 g. 85-88°/15mm 26_ ND - 1.5369, ....... 1. 0 g. d 26_ . 4 - N 20_ D ,- 1.5391. 1.8203, d;O = 1.8274. Regeneration of Methylene Cyclobutane from Dibromide. CH-C.,,..CH2Br I a !'Br CH2 -CH 2 CH-.-c~CHa + 228 104 g Zn EtOH I 2 I CH 2-CH 2 65. 4 = .445 mol 36 g = .55 mol. Procedure: 36 g (0.55 mol) of 30 mesh zinc pellets was placed in a 200 ml. flask and 125 ml. absolute ethanol added. Heated to refluxing on a water bath and 104 g (o.445 mol) of methylene cyclobutane dibromide added slowly. When about 50 g had been added ( 1 hour) solution began to darken considerably and hydrocarbon ceased to come over. Contents of the flask was discarded and new zinc and ethanol replaced. The reaction then continued smoothly until the very end when again the mixture began to darken. Crude hydrocarbon weight 31 18 g, N~ 8 = 1.4201; d; 3 = 0.7326 or rou ghly 90% pure methylene cyclobutane. Acknowledgements The author is greatly indebted to Dr. Edwin R. Buchman for his suggesting this problem and for his guidance throughout the course of the research. The author wishes to ex press his appreciation to Alf Reims for his help in pre paring certain of the compounds used in the investigation. 32 References 1) G. Gu s tavson, J. Prak t. Chem . [2] 24, 97 (1 8 96); G. Gu s tavson, Ibid., [2] 5..§., 93 (1 8 97). 2) M. Idzk ows ka and E . Wag ner, J. Russ. Phys. Chem . Soc., l.Q, 265 (1 89 8 ); C. 1 8 9~ II, . 474. 3) H. Fecht, Ber., iQ, 388 3 (1907). 4) Zelinsky, Ber., 46, 160 (1913); Ze linsky and Krawetz, Ibid., 1§., 1 6 3 (1913); Zelins k y and Schtscherbak , Ibid, 1§., 168 (1 913). 5) O. Philipow, J, Prakt. Chem., [2] .22, 162 (1916). 6) Demj anow and Doj arenko, Ber., 5.2, 2727 (1922). 7) C. K. Ing old, J. Chem. Soc., 123, 1706 (1923). 8) F . Rog ows k i, Ber., 9) Schomaker and Shand, Unpublished data. 10) M . Dojarenk o, Ber.,~' 2933 (1926). 11) Dem j ano w and Doj arenko, J. Russ. Phys. Chem. Soc., 45, 176 (1913); C, 1913 I, 2027 (1 913), 12) zg, 2021 (1939). Friedla e nder, Fortschritte der Te e rfarben-Fabri k ation, D.R.P. 66, 866. 2, 9 8 0 (1 89 0-94); 21.., 1748 (1915), 13) Hibbert, J. A. C. S., 14) An d re Guillemonat, Analles de Chimie,[1:i] 15) Dane, Sc hm idt an d Rautenstrauch, Ann., 2}.g, 33 (1 9 37). 16) Gilman, Org anic Syn thesis, Coll. Vol. I, 417, and Sons , N • Y • 17) Gilman, Org anic Synt he sis, and Sons, N .Y. 18) J. Norris, M. Wa tt a n d R. Thomas, J. A. C~S ., (1916). 19) Fawors k y an d Bat a li n , Ber., 47, 16 2+8 (1914). ,g, 143 (1 9 39 ). John Wiley ll, 73 (1937), John Wil e y 2~, 1076 33 APPEN DIX THE PR.EPARA'l'I ON OF CERTAI N CYCLOBU TANE DERIVATIVES; ETHYL CYCL OBU'l'ANE 1, 1- DI CARBOXYLATE , CYCLOBUTANE 1,1-DICARBOXYLIC ACID, CYCLOBUTANE I!IONOCARBOXYLIC ACID, CYCL OBUTANE :sONOCARBOXYLIC ACID CHLO~IDE, CYCLOBUTANE LIONO CARB OXYL I C ACID AMIDE. 34 THE PR.E PARA 'rI ON OF CERTA I N CYCLOBU'l'ANE DERIVATIVES ; E'I'EYL CYCLCEUT.Aim 1,1- DICAE<°D OXYLA'rE, CYCLOBUTANE 1,1- DICARBGXYL I C ACID , CYCL J EU'r..?,NE l'iOE OCAREOXYL I C AC ID, CYCL OBUTA.l'J E 110 ;. ;o cArtJ"::,CX:CL I C A.CI D CHLORIDE, CYCL02 UTA1-TE ~'.WlW CARE OXYLIC ACID AMIDE. This research had several objectives: (A) A conven- ient procedure for the r,1 re paration of comparat ivel y larg e quantities of cyclobutene; (B) Repetition of the prepar- a tion of cyclobutane deriv a tives for e l e ctron diffraction studies, correspondin5 to th ose of the c yclopropane series being prepared by ~aurice J. Schlatter of this l aboratory . Results. Thirty five mols of trimethylene g l ycol yi ~l ded 31.5 mols of trimethylene dibromi de , 3 . R. 70-72°/30mm, e quals 90% of theory. The dibrornide was condensed with sodium malonic ester and yielded 12.47 rnols of ethyl cyclobutane 1,1-dicarboxylate, B.R. 103-l06°/12rnrn, e quals 39.6% of theory. This ester was hydrolyzed to the 1,1-dic arboxylic acid ' which was decarboxylated to yield 1 0 .95 mols of cyclobutane monocarboxylic ac id, B.R. 93-9 6°/lSmm , equals 88~s of theory. The cyclobutane monoc a r b ox ylic ac i d wa s treated wi th phosphorus tric hlori de and yielded 10.23 mols of cyclobutane monocarbo xy lic a ci :i c hl oride , B . R. 60-65°/60mm, equals 93 ■ 5% of theory. The acid chloride in turn v1as re- ac te d with ammonia yiel di ng 9 .6 mol s of cyclobutane mono- 35 ca rboxylic aci d amide 1'J . P . 155. 9° correc ted, equals 94% theo ry. Over all yield from glycol to amid e equals 27J{;, theory. CH~ CH2 CH 8 CHCH:;- CH,, 2 OH OH Br I I I 2660 g == 35 mols .. I ., Br 636 3 g = 31.5 mols B.R. 70-72°/30mm CH-CH-COOH 2 I I CH:r- CH2 B.R. 1 03-l06°/12mm B.R. 93-96°/15mm 2494 g = 12.47 mols 1095 g = 1 0 .95 mols CH-2 -C H--COCl CH2 Crt;a-- CH - 2 CH 2-CH 2 I I I p CH-CONH2 I B .R. 60-65° /60mm M.P. 155.9° corr. 1213 g == 10.23 mols 950 g = 9.60 mols A preliminary ex peri me nt on the cyclobutane monocarboxylic acid amide, in which an attempt was made to convert it to cyclobutylamine usi ng hypobromi te, was not satisfactory and attention was then turn ed to the comparatively sim ple preparation of methyl cyclobutene in order to gain ex perience in the technique of handling these volatile, unsaturat e d, cyclic hydrocarbons. Various reactions co uld then be tried out first on the mo re easily obtainable methyl derivative. clusive. This r e s earch is described on pages l-3Q.. in- 36 A detailed description of the experimental procedure follows: Trimethylene Dibromide. Br 2 2HB r + + 160 2400 g = 15 mols CH 2- I CH2- C H2 I OH OH + CH,,- CH 8- I~ 2HBr Br 76 912 g = 12 mols / CH 0 ~ Br + 2H 2 0 202 Xield! 2180 g of trimethylene dibromide, B.R. 70-72°/30 mm, equals 90 %· The procedure outlined in followed rather closely. quantities specified. Organic Synthesis 2 was A typical run consisting of double A twelve liter round bottomed flask, surrounded by an ice bath and fitted with stirrer was used for the reduction of bromine to hydrobromic acid. 2400 g (15 mols) of tecbnical bromine wes poured over 2600 g of ice and sulfur dioxide passed in with agitation, at a rate adjusted for complete absorption. 2 hours. Time required, Reduction was considered complete when the deep red solution changed to a straw yellow. The solution of hydrobromic acid was then thoroughly cooled before attempting to add the glycol and sulfuric acid. 912 g (12 mols) of commercial trimethylene glycol and 2400 g (24 mols) of concentrated sulfuric acid were added to the cool solution with agitation. This mixture was refluxed for 5 hours and then distilled until no more dibromide 37 came over. Di s tilling ti me, 3 1/2 hours. The cru de di- bromide was s e parated from the wa t e r, wa s he d t wice with water, once with 4 00 g of concentrated sulfuric acid, once wi th one liter of 10% sodium carbonate solution and finally with wate r, then dried over 50 g calcium chl oride. The crude, dry di bromide whic h wei g hed 225 0 g wa s then distilled at reduced pressure. . . . . . 5 g. 68-70°/30mm .. . . . . 45 g • up to 68° /30mm 70-72°/30mm .•.... 2180 g. 72-73°/30mm ...... 20 g. Ethyl Cyclobutane 1 2 1-Dicarboxylate. 2Na + CH -COOEt 2 -cooEt + Br ( CH13 ) 3 Br EtOH ~ 160 202 23 322 g = 14 mols, 1120g= 7 mols, 1414 g = 7 mols. I 1 8 ,,,,,.,. COOEt 2 CH 2200 --cooEt CH 2 Xield: 598 g of crude este r B.R. 77-115°/2mm, equals 42.8% or 550 g redistilled ester, B.R. 103-l06°/12mm, equals 39. 2% of theory. Procedure: A twelve liter flas k was fitt ed with a three opening ada pter carrying two Friedric h t ype reflux condensers, the cente r opening being used to a dd the sodium metal portionwise. The flas k was placed in a buc k et to provide for cooling should the reaction get out of hand. Calcium chloride guard tub es were used on the condensers. Six liters of absolute ethanol were placed in the flask and 322 g (14 mols) of sodium added in portions of about 25 g ev e ry fifteen minutes, just enough to k ee p t h e alcohol reflu x i ng slo wly. This s oluti on of s odium ethylate 38 may be allowed to stand for a day if ti ghtly stoppered. For the condensation between the dibromide and malonic ester another twelve 11 t0r flask was used. 'Ihe flask was fitted with a three opening adapter carrying two reflux condensers, an inlet tube for the alcoholate solution and a merc~ry sealed stirrer in the middle opening. 1414 g of trimethylene dibromide (7 mols) B.R. 68-73°/3omm, plus 1120 g malonic ester (7 mols) of Eastman product, redistilled, B.R. 95-lOO°/2omm were mixed together in the flask and heated to 80° on a water bath, and then the sodium ethylate solution was forced in with vigorous stirring over a period of about one hour using dry air pressure to force the solution from one flask to the other through rubber tubing. 'rhe mixture was then refluxed and stirred for about half an hour, or until a small sample when diluted with water was neutral to litmus. The excess alcohol was distilled off on a boiling water bath usi ng agi tation to prevent bumping. About 5. 5 liters of alcohol were re- covered and re-used. After removing the alcohol, the mix- ture was cooled and two lit e rs of cold wa ter were added to dissolve the precipitated sodium bromide formed in the reaction. The oily phase was then removed in a separatory funnel and the aqueous phase extracted once, using about one liter of diethyl ether. This ethe r e xtract was com- bined with the bulk of the ester and the whole was dried over 60 g of anhydrous sodium sulfate. After drying, the ether solution was filtered, the sodium sulfate washed 39 with a small amount of ether, and the combined ether solutions added from a two liter separatory funnel to a three liter flask fitted with a short distilling head. The ether was distil led off on a steam cone using the aspira tor to remove the last traces. An oil bath was then substituted for the steam cone and the oily residue distilled at reduced pressure . The thick, viscous residue, which sets to up to 77° /4mm • . . . . . . . . 10 g. 77-115°/2mm •....... 598 g. residue ........ 66.LJ- g. a hard crystalline ill ass upon cooling, consists principally of ethyl pentane tetracarboxyla te. The crude ester· boiling at 77-115°/2mm was then refractionated using a 200 x 25mm column packed v1ith helices. . . . . . . . . 12 g. 103-l06°/12mm . . . . . . . 550 g . residue .. . . . .. . 30 g • 55-103° /1 2mrn . N~":;l . lJ-325 Some of- the fraction boiling at 103-l06°/12mm was again fractionated for physical properties . B.P. 104.5°/12mm, The above procedure was found to be most convenient and to g ive the highest yields. Using methanol instead of ethanol seemed to result in a mixture of esters since a pure fraction could not be obtained by a simple fractionation. Ring'closure using cyanoacetic ester instead of malonic ester gave no better yields and required a more careful fractionation. Using the procedure outlined by 40 Perkins;;,, yields averaging 32% wer-e obtained as compared to the 39% by the procedure de s cribed here. Cyclobutane 1,1-Dicarboxylic Acid, Cyclobutane M.£n.£_£Qrboxylic Acid. CH I s C_.-C OOEt -c ou.tEt + 1 2KOH C 2 Hg ou H T CH 2-CH 2 200 600 g = 3 mols CH 12 mols 56 672 g = 12 mols C,,..COOH I 2 I' c rV-c ,i:.:· CH~CH-COOH C-lP ~ CH 2 CH-CH 2 2 I ·. i 144 I 100 Yield: 264 g of cyclobutane monocarboxylic acid B.R. 93-96°/15mm equals 88% of theory. Procedure: The hydrolysis was carried out in a five liter three necked flask fitted with mechanical stirrer, conden ... ser, inlet tube for alcoholic potassium hydroxide solution and surrounded by a water bath. 672 g (12 mols) Merk re- agent potassium hydroxide was dissolved in three liters of 95% denatured ethanol and forced with vi g orous stirring into 600 g (3 mols) of e thyl cyclobutane 1,1-dicarboxylate B.R. 103-l06°/12mm , N2 6 = 1.4325. D When about half of the a lkali was in,the mixture set to a curdy semi-solid mass that wa s very difficult to break up. When all the potas- sium hydroxide solution had b e en added, t he mi xture was refluxed with stirring for 1.5 hours. The alcohol was then 41 taken off on an as pirator, one 11 ter of water added and then evaporated to dryness, leaving a mixture of potassium salt of cyclobutane 1,1-dicarboxylic acid and excess potassium hydroxide. The dry salt mixture was dissolved in 500 cc of water and cooled before neutralizing the excess potassium hydroxide. 600 g of concentrated sul- furic acid was poured into 600 cc of water and the diluted acid was added slowly, with cooling to the salt solution. After the excess potassium hydroxide was neutral- ized, 600 g of concentrated sulfuric acid was added. held the solution to a minimum volume. This The solution was then filtered on a sintered glass funnel to remove the mixture of potassium sulfate and acid sulfate t ha t had crystallized out. The clear solution was then put on con- tinuous ether extraction for twenty four hours using about 1500 cc of alcohol-free diethyl ether. The mixture of potassium sulfate and acid sulfate was dissolved and extracted with a small amount of ether which was combined with the bulk of the ether in the continuous extractor. The ether so lution, without drying, wa s a dded slowly to a 500 cc Claissen flas k and the ether distilled off leaving a somewhat discolored crystalline mass of crude cyclobutane 1,1-dicarboxylic acid. 'r he oil bath was then raised to about 200° where the mass melted and carbon d i ox i de was g iven off. The temperature of the bath was then lo we r e d to 180° where the crude cyclobutane monocarboxylic acid slowly distilled at about 30mm pressure . It was found that if the decarboxylation vms a tte mpted a t a temperature L+2 higher than 200° much frot h i ng res u lt ed . Wei g ht of crude c .:r clobutane rn onocarboxylic aci d was 29L~ g. This crude material was then fractionated usi ng a 200 x 25 mm column pa cked with helices. Some of the material boiling at u p to 93°/15 mm ..... 20 e. 93-96°/lSrnm •.... 264 g. 96-110°/15-lOrnm .. 5 g. 93-96°/15 mm was refrac tionated for physi cal pr operti es . B .P. 95.5°/15mm, F 1. 6 _ 'n - 1.4450 Pure cyclobutane 1,1-dicarboxylic acid may be prepared by evap~ rati n g the ether solution , obtained from the conT tinuous extraction at room te mpe rature using an aspirator. The crystalline mass thus obtained is pressed out on a por ous plat e t o re move small a mounts of cyclobutane monoc a rboxylic ac i d and perh a ps some unsa p onified e ster, redisso lved in ether and allo wed to crystallize sl owly by p ermitting the ethe r to slo wly evaporate. In one i ns tance recrystallization wa s repeated five ti me s and resulted in cry stals having a neutralization equivalent of 71.9. theory for C6 H8 0 4 equals 72.0. The proc e dures outlined above were found to be mo st c onvenient of t hose tri ed . P ot a ssium rathe r t han so d ium hyd r oxyd e was used be c aus e of its g re a t e r sol ub i li t y in ethanol. ~ e t hanol may be sub stituted for ethano l with no bad e ff e cts, however, if wat e r is use d as solvent, a much longe r period of refluxing is required for complete sapon ification. 50,% HCl was tried and gave fair yields Aqueous in some cases but in one experiment, after having refluxed for fifteen hours, a very high boiling viscous yellow resi due contain ing chlorine resulted and the yi e l d of c y cl obu.ta.n e mor,iocarQ oxylic acid_ vva.s pro portionaJ_l~y lovJ er· . B . P . of t he c h lori ne containi ng residue wa s CH2- C H-C OCH 3 I I 3 + PC1 3 100 150 6 /5mm . r ~r~ 1 H-C 8Cl + H 3 P0 3 Ci1 2- C H 2 118 .5 137.4 366 g = 8/3 ~ ols. Ll- 00 5 = 4 mols Xield: 427 5 of cycl ob utan e monoca.rboxylic ac i d· c hlo r i d e B . R. 60 -65° /60mm . By re-using the r e covere d ph os phorus tri- chloride approx i mately 17 g of acid c h loride is recovered ma k ing a total of 444 g equals 93-5% of theory. Procedure: Ground g lass equipmen t used t h ro ugho u t. li-00 g of cyclobutane monocarboxylic acid (4 rn ols) B . R . 93-96° /15 mm was placed in a on e liter flask which wa s fitt e d with a reflux condenser and g uard tube. chloride (2. 66 mols) 366 g of phosphorus tri- B.R. 73.5-75.5°/750mm, freshly dis- tilled, was a dd ed and t he mi x t ure heated on an oil bath at 100-110° for one hour. The te:nperature and l eng t h of heating are both critical. Above 110°, de compos ition is extens ive, result i n g i n 30% yie l d of t he a ci d chlori d e if re a ction tak es place at 130-140 °. The reaction product was then cooled and the mi x t ure of excess phospho rus tric h loride and acid c h lori de was caref u lly dec an ted from the syrupy ph os ph orus acid into a one lit e r d istilli n g f l ask . The syrupy residue amoun ting to about 125 g was washed with some phospho rus tric h loride which wa s then combined with the bulk of the material. The distillin g f l ask was connected to a 200 x 25mm fr ac tionati ng column packed with he lices, and the ma terial fra ctionated using the asp irator. A dry ice tra p was used in th e vapor lin e to the as p irator. During the distillation the t em perature was not allo wed t o rise above 110 °. The recovered phospho rus .... ... ... 176 g • 60-65°/60mm . ... . . . . . . 427 g . 35-60°/60mm trap 75 g . trichloride was reu se d and yielded a ~Jp roximately 17 g more of t he acid chloride mak ing a total of 44L~ g , 3 .R. 60-65°/60mm. Us ing this p rocedure a total of 10.95 mols of cyclobutane monocarboxylic acid was converted to 10.23 mols cyclobutane monocarbo x ylic acid chloride. Acid chloride boiling at 60-65°/60mm was refractionated and the bulk of it came over ~t 65Q/6Omm or 62.5°/50mm. A sample of this re- fr ac tiona t e d mate rial was gi ven to Werner Schomaker for electron diffraction study. 45 Cyclobutane I11onocaE,Q.£2:£Ylic Acid 1-\mide . excess + 118.5 2NH 3 .iJ. liters t;the r 34 99 355 .5 g = 3 mols Xield: 279 g of cyclobutane monocarboxylic acid amide, ~ .P. 155.9° corrected, equals 94% of theory. Procedure : Note- All apparatus was thoroughly dried and precaution s taken against moisture entering the ap paratus during the reaction. Apparatus used consisted of a dry five liter three necked flask fitted with a mercury seal stirrer, ammonia gas inlet tube, dropping funnel and gas exit tube and surrounded by an ice bath. Four liters of diethyl ether, previously dried for 48 hours over sodium wire was decanted from the sodium into the five liter flask and saturated with dry ammonia gas at o0 • half an hour being required. About 355.5 g of cyclobutane mono- carboxylic acid chloride (3 mols) B.R. 60-65°/60mm was added over a period of half an hour in 50 g portions. allowed to trickly in, the inlet tube clogged. If The mixture was stirred and ammonia gas passed in for two hours after all the acid chloride was in. Completeness of reaction was tested by di luting a small amount of the mi x ture with water and t esting with litmus. After ammonia was in excess, the stirrer was removed and a large bore capillary substi tuted. The ca pillary tube carried a calcium chloride guard tube. The ether was taken off on a steam c one using the 46 aspirator. The amide showed a tendency to sublime after all the ether had been removed. The dry mixture of' amide and ammonium chloride weighed 465 g indicating that the aci d chloride con tained about 2-5% im purity calculated as phos phorus trichloride. The mixture of amide and ammonium chloride was scraped from the flask and placed in Soxhlet ~xtractors and extracted continuously for 20 hours with chloroform. The second and third crops of crystals can be recrystallized if necessary and will yield about 120 g of cycl obutane monocarboxyli c acid amide, .M . P. 155 .5 ° corrected. First crop of crystals • • • • 160 g, IvI .P. 155.9° corr. Second crop of crystals .... 100 g, M.P. 155.0° corr. Third crop of crystals .... 25 g, M.P. 144-146° corr. By this procedure a total of 11.21 mols of cyclobutane monocarboxylic acid chloride was converted to 10.25 mols of cyclobutane monocarboxylic acid amide, M.P. 155.5° corre cted, equals 94% of theory. References: 1. Wills tatter and von Schmaedel, Ber., 2§., 1992 (1905) • Willstatter and Bruce, ibid, 40, 3979 (1907). Willstatter and Bruce, ibid, 41, 1486 (1908). 2. Organic Synthesis, Collective Volume!, 28. 3. Perkin, J. Chem. Soc., 51., 2 (1887). Perkin and Sinclair, ibid, 61, 40 (1892) ■