The Reaction Between Oxygen and 2-Butene Citation Prater, Arthur Nickolas (1933) The Reaction Between Oxygen and 2-Butene. Master's thesis, California Institute of Technology. doi:10.7907/NNVD-0F26. https://resolver.caltech.edu/CaltechTHESIS:03012017-102431032 Abstract 2-Butene has been found to react with oxygen at temperatures of 375° to 500°. At the higher temperatures, polymerization as well as oxidation takes place. The products of the reaction which have been identified are acetaldehyde, glyoxal and/or glycollic aldehyde, 1,3-butadiene, acid, peroxide and an olefin oxide. The simplest explanation of the reactions occurring involve both hydroxylation and peroxide formation as primary products. 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): Unknown, Unknown Thesis Committee: Unknown, Unknown Defense Date: 1 January 1933 Additional Information: Author's name is spelled Arthur Nichols Prater in the 1933 Commencement program. Record Number: CaltechTHESIS:03012017-102431032 Persistent URL: https://resolver.caltech.edu/CaltechTHESIS:03012017-102431032 DOI: 10.7907/NNVD-0F26 Default Usage Policy: No commercial reproduction, distribution, display or performance rights in this work are provided. ID Code: 10083 Collection: CaltechTHESIS Deposited By: Benjamin Perez Deposited On: 01 Mar 2017 19:07 Last Modified: 16 Aug 2023 23:10 Thesis Files Preview PDF - Final Version See Usage Policy. 4MB Repository Staff Only: item control page

IBE REACTION BETWEEN 02'Y. GEN AND 2-BUTENE Thesis by Arthur Nickolas Prater In partial fulfillment of the requirements for the degree of Master of Science in Chemistry California Institute of Teahnology Pasadena, California 1933 THE REACTION BETWEEN OXYGEN AND 2-BUTENE INTRODUCTION At the present time the mechanism of the gaseous oxidation of hydrocarbons is in dispute. During the latter half of the 19th century some investigators held tha.t in the combustion of hydrocarbons the hydrogen is preferentially burned. In opposition to this was the claim that the carbon is preferentially burned. In 1902 Bone 1 proved that there is no preferential burning of either carbon or hydrogen and advanced the idea that the oxidation of hydrocarbons proceeds through Ethene when oxidized was found by Bone and Wheeler hydroxylation. 2 to yield small amounts of acetaldehyde in addition to carbon oxides, water and other secondary reaction products. The acetaldehyde was postulated as being formed by rearrangement of vinyl alcohol , the primary reaction product. ~ CH2=CHOH vinyl alcohol ~ CH 3 -CHO a.cetaldehyde Vinyl alcohol is known to rapidly and quantitatively isomerize to ace t a lde h y de. . t iga. · t ors . 3a-f have present ed much Bone an d oth er inves additional evidence in favor of the hydroxylation theory of oxidation of hydro carbons. Some recent investigations, however, have indicated that oxidation proceeds through the forma~ion of a primary peroxide, this peroxide then.reacting with additional hydrocarbon molecules or else decomposing to yield the final reaction products. Thus Cal lendar and Mardles 4 propose the primary reaction of oxygen with methane to be 2. a.s follows: CH 4 + 02 methane Recent work on ethene ---> CH 3 00H methyl hydrogen peroxide 5a b c 5d 5e 5f , , , propene , pentenes , cyclo- hexene , and 5 styrene g has indicated that the reaction products of oxidation can be most satisfactorily accounted for by assuming the reaction to be initia.ted by the formation of an active or "dative" peroxide. It was thought that the oxidation of 2-butene under conditions which would enable the isolation of the primary oxidation products would throvr some li ght on the mechanism of gaseous oxidations in general. Accordingly a study has been made of the oxidation of 2-butene using a short time of contact in the heated reaction z~ne and an amount of oxygen much less than required for complete combustion. 3. EXPERIMENTAL Materials: The 2-butene was prepared by heating 100 ml. n-buta.nol (Eastman no. 50) with 100 ml. 95% C.P. sulfuric acid and 50 ml. water in a 1-liter, 3-neck flask. '.Ihe butene is purified by passing through a spiral reflux condenser, through three spiral wash bottles, the first two of which contain 40% by volume of sulfuric acid to remove alcohol vapors while the third contains 40% potassium hydroxide solution to remove any traces of sulfur dioxide, through a tower half filled with soda lime and half with calcium chloride, and is condensed in a trap immersed in a freezing mixture. Youn~ and Lucas 6 have shown that butene so prepared consists entirely of cis- and trans2-butene. Apparatus: The oxidation apparatus is shown in figure 1. A to H consists of a device for delivering gas at a constant rate. Various other apparatus were tried and found to be unsatisfactory. The apparatus here described wa.s found to be very satisfactory in that a constant, non-fluctuating flow was quickly and easily obtainable. ABC is a 14 mm. tube projecting about 100 cm. above the top of the five-gallon bottle, D. At the point B, the tube ABC is con- stricted by a 5-cm. length of 1 mm. internal diameter capillary tubing. Just below this capillary tube, the tube ABC has a pinhole, PH, which allows the pressures to be equal in the bottle and in the tube ABC below the capillary. the bottle. tower. E is a 6-mm. tube extending to the bottom of F is a 6-mm. delivery tube. H is a sensitive needle valve. G is a calcium chloride ~=====-------) ~ 11'======--_j ) ~ ·~~)0 5. To use the apparatus, water is run into A, most of which overflows to the sink. Tube AC fills up, with water flowing through the capillary B into D under an effective head of water equal to the distance AB, 100 cm. The needle valve, H, is kept closed until the pressure in D builds up to 100 cm. water when the back pres sure just balances the column of water AB. into bottle D. At this point water stops flowing Then the needle valve 1 H1 is opened and adjusted to give the desired rate of flow. The portion BC of tube ABC prevents exces- si ve washing of the butene mixture by the falling streirn of water. After leaving the needle valve, the gas mixt~re pas~es through a flm"lilleter and into the reaction tube, I, heated in an electric furnace. J. The reacted gases are cooled by a condenser, K, and ice trap L. The cooled gases pass through two water-filled spiral wash-bottles M1 and M2 to remove water-soluble reaction products, through trap o cooled 1 in an ice-hydrochloric acid mixture, and then through two traps, 02 and 0 3 , cooled in solid carbon dioxide-alcohol mixture. The uncondensed gases a.re collected in the rubber balloon, P. 1.P '.rhe re action tube consists of a 7-mrn. 1\pyrex tube, 30 cm, of which is inside the furnace. Temperatures inside the reaction tube are measured by three chromel-alumel thermocouples fused in the reaction tube at equal intervals. The furnace temperature was measured by an additional thennocouple located alongside the reaction tube. A ]Leeds and Northrup student type potentiometer was used to measure the therraal electromotive force. The temperature of the reaction tube is taken as that indicated by the thermocouple in the middle of the reaction tube. The flowm.eter was calibrated by passing a butene-oxygen mixture through it at a definite measured rate. It was .found that the 6. rn1 xttJt-e. indicated rate of flow of the butene-oxygenAthrough the flo¥nneter calibrated with air was 35% lower than the actual rate. .F'or this reason it was necessary to recalibrate the flow:meter using a buteneoxygen :mixture of the same composition as the n1ixture used in the experiments . Before starting a.n oxidation, butene was volatilized into a 5-gallon bottle displacing brine. Oxygen was added in the desired amounts from a cylinder and the mixture allowed to stand overnight to insuce thorough mixing , '.Ihis gas mixture was then driven into the bottle D just before an oxidation was started. During e.n experiment the gases were passed through the furnace at an average rate of 62,2 ml. per minute , with a contact time of 11 seconds. The oxidations were continued for about three hours in order to collect appreciable amounts of the reaction products. Imme- diately after completion of an experiment the exhaust gases were transferred from the balloon to a glass flask and stored over mercury. 7. ANALYSIS OF REACTION PRODUCTS Gas Samples: The samples of the entering gas were analyzed in an Orsat apparatus. The ex.haust gases were analyzed by a combination of an Orsat analysis and a distillation analysis through a Podbielniak column 7 • Unfortunately the latter results will not be available for a short time, The available results e.re incorporated in Table II. Condensates in ~raps 01, ??' and 0 3 ; The condensates in these traps consisted almost entirely of buta.diene and unreacted butene. These were converted into the corresponding tetra- and di-bromides by distilling the condensates through a column of bromine kept in the dark and at a temperature only slightly above the freezing point of the bromine.ting mixture. The apparatus used for this conversion is shol)lm in figure 2. 2 1 z 8. The condensate is volatilized from trap 1, through the colu.1Ul of bromine into trap 2. One passage through the bromine gives pr¢actically complete absorption. Some bromine vapors pass into trap 2 and there react with any unreacted condensate. The bromine used was purified by washing with saturated potassi~~ bromide solution and then distilling from concentrated sulfuric acid. The brominated condensates were washed with an excess of sodium bisulfite solution, washed well '.rith sodium bicarbonate solution, washed with water, dried over calcium chloride, and distilled through a vacuum jacketed Vigreux column designed by Weston 8 • The residue in the flask crystallized on cboling and was the tetra.bromide of 1,3-butadiene. This was established by its melting point and by a mixed melting point with knovm buta.diene tetra.bromide. The distillate consisted of dibromobutanes. By subtracting the amount of butene recovered as dibromobutane from the amount of butene passed,, the amount of butene reacting was found. The results are best shovm in figure 3. in which the percent of butene reactiK>~ per mole of butene passed is plotted against the temperature. ~ ~ ~ ~ ~ ~ ~ JO 2D /V ~ .. tfOO TEMPER/ITC/RE 9. At temperatures below 400° very lit tle reaction takes place. At temperatures above 500° soot is formed i ndicating that secondary ·reactions are occurring. 'lhis amount of butene re acting is not neces- sarily a measure of the primary reaction as butene may be involved in sec ondary re a ctions. Wash Waters: More will be said of this later. Total aldehyde was determined in the wash waters by a gr avDnetric determination of the total weight of dinitrophenylhydrazones which were obtained from an aliquot of the wash water on adding an excess of dinitrophenylhydrazine. This method is based on the as- sumption that the aldehyde is all present as acetaldehyde. Actually acetaldehyde constituted at least 90% of all aldehydes present. The anal ysis of the carbonyl compounds was effected by identification of the 2,4-dinitrophenylhydrazones prepared after the method 9 of Brady • .A:n aliquot of the precipitate d hydra.zones was fractio nally extracted and crystallized by means of alcohol. separated into tvm components: The derivatives were (a) a relatively insoluble osazone of glyoxal (or glycollic aldehyde) and (b) a less insoluble hydra.zone of acetaldehyde. It is not possible by this method to distinguish bet·ween glyoxal and glycollic aldehyde as both yield the same osazone. It was Dnp o ssible to isolate any 2,4-dinitrophenylhydrazone of the following: fonnaldehyde, propionaldehyde, n- or iso-butyraldehydes, crotonic aldehyde or methylethylketone. In calculating the composition of the ori ginal hydra.zone and osazone mixture it was assumed to consist of only derivatives of a.cetaldehyde and glyoxal and that the recovery of the glyoxal osazone was quantita.ti ve. To facilitate the identification of t he reaction products 10. the dinitrophenylhydrazones of the following compounds were prepared. The derivatives are listed in Table I along ~dth the melting points, color and crystalline form. T.ABLE I. 2,4-DINI TROPHENYLHYDRAZOiiTES Compound Melting Point °Cobs. Literatu re Values formaldehyde 166 155 orange plates acetaldehyde 150. 2 147 yellow powder propionaldehyde 158 155 brilliant red plates n-butyraldehyde 120 122 orange needles iso-butyraldehyde 182 182 orange prisms 158.(dec) 165 red powder 187.5 190 fine red crystals 322. (dee) 318 orange crystals acrolein crotonaldehyde glyoxa.l* Color and crystalline form methyl glyoxal 158. orange methyl glyoxal * 250.(dec) orange dimethylketone 125.8 128 yellow needles and prisms methylethylketone 112. 5 115 orange needles and plates methylpropylketone 137.5 141 orange needles methylcyclo-hexylketone 139. 140 orange glyoxalic acid · 195. 190 red plates pyruvic acid 197.5 213 yellow needles * osazone 11. '.L'he n- and iso~butyraldehydes were prepared by oxidation of n- a.nd iso-butyl alcohols ¥rith chromic acid. 'Ihe glyoxal was prepared by oxidation of ethene with selenium dioxide according to the method of Riley and Friend 10 • 'Ihe methylcyclohexylketone was prepared by chromic acid oxidation of methylcyclohexyl carbinol. 'Ihis carbinol was pre- pared by adding acetaldehyde to cyclohexylmagnesiwn bromide and decomposing the addition compound with water. 'Ihe other carbonyl compounds were purified from samples obtained from the supply room. In connection with the use of 2,4-dinitrophenylhydrazine as a reagent for carbonyl compounds it was noticed that the ordinarily available reagent consisted of a mixture of yellow and red crystals when viewed under the microscope. Under proper conditions it was possible to make the sybstance crystallize out in either the yellow or the red form, depending upon the solvent used. It was further noticed that the yellovr apparently changed over to the red form when heated. Report of this phenomenon has not been located in the literature and may warrant further investigation. The acid in the wash waters was determined by titration with standard sodium hydroxide solution using phenolphthalein as an indicator. Peroxide was tested for qualitatively with titanium tetra.chloride in 6-normal hydrochloric acid 11 • 12. CONDENSATE I N ICE TRAP The condensate in the ice trap varied from a few drops at the lower temperature up to 8 0 9 ml. at the higher temperature per mole of butene passed. At temperatures above 450°, the condensate consisted of tv;o phases; the upper phase was an oil of density less than one. Both phases had very penetrating odors, gave positive tests for peroxide, good i _o dofonu tests,, and reacted acid to litmus. The molecular weight of the oil phase was determined by reacting a portion with standard bromide-bromate solution in the presence of excess acid. Assuming one aouble bond per molecule the molecular weight of the oil was found to be 124 - 125. The value for octene is 112. Evidently the oil phase is impure octene formed by the polymerization of two molecules of.butene. RESULTS AN D DISCUSSION OF RESULTS The experimental data and results of the analyses are shown in Tables II and III. 59.3 65.0 456 490 192 199 185 1.2 o.3 0.9 456 490 1.7 0.1 415 Entering Gas 41.4 39.4 40.l 2. 2 7.0 4.7 46.4 0.2925 TABLE III 43.3 51. 6 o. 2152 0.2080 0.2390 Dibromobutane isolated moles gms. o.2660 o.2650 C4H8 passed % N:a moles Mol. wt. Oil 124.2 0.0438 o. 0379 0.0127 95-97 88-92 97-98 5-3 12-8 3-2 2,4-dinitrophenylhydrazones Total Approx. Percent moles acetald. glyoxal + + + + o.oons + Iodoform Test I-' UI . Flow very constant Used device described 0.000164 Remarks ) Flow fluctuated ) due to poor gas ) delivery device. + Acid Equiv. 0.00937 0.00509 0.00380 Peroxide Quali ta.ti ve Test 3.5 1.9 1.4 Tetra.brombutane isolated moles gms. Analysis of Wash Waters and Ice-trap Condensate 56.4 53.6 55. 2 % C4H8 % 02 125.o Length of exp. min. Ice-trap cond. Water Temp. Oil oc ml ml 62.3 415 · Ave. rate · Temp. of flow oc ml/min Experimental Data and Analysis of Condensates TABLE II 14. These results~ recalculated on the basis of moles of products formed per mole of butene passed are shown in Table IV. TABLE IV Moles Product per Mole Butene Passed Temp. oc Butene reacting moles Butadiene formed moles Total aldehyde moles 0.4 0.098 o. 0159 o.o4so + Ice-trap cond. Oil Water ml ml 415 Acid equivalents 456 1.1 4. 5 0.218 0.0191 0.1425 0.00445 490 3.1 5.8 o.265 0.0321 0.1496 0.00056 These results are in general agreement with the corrected . 12 • resu lt s OL~ Ross Morris Unfortunately the original cal culations a.re in error due to a large error in the flowmeter calibrations. Using Morris' original data and applying the correct flowmeter readings the results in Table V are obtained. same in both cases . The experimental conditions were the 15. TABLE v Moles Product per Mole Butene Passed Total Temp. aldehyde oc moles Acid equiv. Olefin oxide moles Peroxide equiv. 375 0.0356 + + 391 0.0366 + + 418 0.082 0.0204 0.000805 + 421 0.084 0.0130 0.00388 0.00956 447 0.1620 0.0214 + + 472 o.1396 0.00525 0.000732 0.00613 485 0.1055 0.00430 o.o 0.00503 + Morris also observed that the aqueous phase of the condensate gave a positive test for formic acid when heated wi.th powdered mercuric oxide • . The results of the oxidation may be explained in a variety of ways. If the initial reaction is one of hydroxylation two products might be expected. They are the encl form of methylethylketone,, of methylethylketone were formed it would immediately isomerize into the keto form. This was not found among the reaction products. According to Pope, Dykstra and Edgar13 ,'oxidation of hydrocarbons proceeds by an attack at the end of the chain. formed. If this occurs,crotyl alcohol might be Crotyl alcohol at the high temperatures might undergo an allylic rearrangement to yield methylvinylca.rbinol. CH 3 -GH=CH-CH2 0H crotyl alcohol ----'> CH 3 -CHOH-CH=CH2 methylvinylcarbinol 16. This rearrangement seems entirely likely as bromine derivatives of similar compounds are lrnown to undergo allylic rearrangements at temperatures much lower than those attained in the oxidation apparatus. If methylvinylcarbinol were formed it might lose water and form 1,3-butadiene. CH 3 -CHOH-CH2 = CH2 ---7- methyl vinylcarbinol CH2 =CH-CH=CH2 + H2 0 1, 3-butadiene The presence of crotyl alco hol and methylvinylcarbinol has not as yet been established in the reaction products. Butadiene, however, has been found to be present at all temperatures studied. Its presence is best explained through the pyrolysis of methylvinylcarbinol produced as explained above. Butadiene might conceivably be formed from the elimi- nation of water between a molecule of 1-butene and oxygen, the 1-butene being formed th r ough rearrangement of 2-butene. If, ho~vever, considerable amounts of 1-butene were formed, formaldehyde and propionaldehyde would be expected to be an1ong the products. Neither of these were found. It is probable, however, that any fonna.ldehyde formed would be ilmnediately decomposed. Bone 14 re po rts that formaldehyde is rapidly decouposed above 400° while Bone and Stocking15 report that other aldehydes a.re decomposed at much lower temperatures according to the reaction: CH 3 CHO Some formaldehyde is undoubtedly fo:nned in this reaction from the oxidation of butadiene as glyoxal and/or glycollic aldehyde is formed. This can best be explained by the following reaction: CH2 =CH-CH=CH2 buta.diene + 202 ~ CHO-CHO + 2HCHO glyoxa.l formaldehyde It is possible that this reaction proceeds through an intermediate peroxide. 17. While the formation of butadiene can be best explained on the basis of hydroxylation, the ma.in oxidation reactinn, the formation of acetaldehyde, can be best explained on the basis of peroxide forroation. 'Ihe peroxide would be formed from a molecule of butene and one of oxygen as follows: CH 3 -~;rH-CH 3 2-butene 2-butene peroxide This peroxi9e then might react in a variety of ways. The main reaction is the thermal decomposition into acetaldehyde. CH3-~H-C-.tl3 while a second reaction might involve an unreacted butene molecule to yield butene oxide: C-.tl 3 -ey-CH 3 + CH 3 -CH=CH-CH 3 ~ 2 CH 3 -C~~-CH 3 butene oxide If this reaction occurs some of the butene is then disappearing in a secondary reaction and the amount of butene used up is not a criterion of the amount of prL~ary reaction occurring. '.Ihe peroxide might a lso react with water to form hydrogen peroxide and butene oxide: l\:ny hydrogen peroxide so formed might react with aldehydes to give hydrogen, saturated hy~rocarbons and acids as Fry and Payne 16 have shown that formaldehyde reacts with hydrogen peroxide in the presence of sulfuric acid to give hydrogen and formic acid, while paraldehyde reacts to give formic and acetic acids and methane. 18, The amount of polymerization occurring is no doubt more than would have occurred if oxygen were absent as Engler 17 found that oxygen markedly increased the rate of formation of polymers from olefines and dienes, As accurate analyses of the exhaust gases a.re not yet available, it is not possible to state at this tDne the extent to which the butene suffers pyrolysis, The results are diagrammatically shown in Chart l, Chart 1 ( C~H6)x. fl>/~.,,-,,,1,.,, ,, C H,_Ol-1 cH~ I CH -1/.z.O lI cH CHO ~~ )> I + 2HCHO (HO fOr-m~h.v/e 8_ H-- CH:1 ZHz. +zco cr-ofyl <J/ctJhtJI 177efl,y/-v/hyl Cd,-b;nt7/ cH1 I CH- CH (I CH t H~ Z-6ufe;,e c ~3 CH3 I 02 I )>, CH- I C l{r ~ ' Cflb \ ~z 'J. Cl+.J c H.'1 ~2C0+ZC/-lq I CHO cu, I 1~ -b fene .Z-bvlne 178;-. 2C2./·h (Cqlh/ x etheJ?e tJC./E'ne ek oceraldehytle x 111 e +C<f ~HJ' I-I"(, CJV Ct-1-i 2-b<Jkhe "x itle c;- c H.r d H, l ~H,JJ I c. rf3 2-/JfdP~e o.xide me/1JqJ'1e l&. SUTuIMARY 2-Butene has been found to react ~~th oxygen at temperatures of 375° to 500°. At the higher temperatures# polyrfreriza.tion as well as oxidation takes place. The products of the reaction which have been identified are acetaldehyde, glyoxal and/or glycollic aldehyde~ 1,3-butadiene, acid, peroxide and an olefin oxide 12 • The simplest ex- plana.tion. of the reactions occurring involve both hydroxylation and peroxide formation as primary products. 20. REFERENCES 1. Bone, J.Chem.Soc., ~· 536 (1902)~ 2. Bone and Wheeler , ibid., 85, 1637 (1904). 3. (a) Bone and Stocking, ibid., 85, 722 (1904). (b) Bone and Drugman, ibid., 89;" 660 (1 906 ). (c) Drugman, ibid., 89, 939 (1906). (d) "\l'. lheeler and Blair,- J. Soc. Chem. Ind., 303 T, 1922; 81, 87, 415 T, 1923 • . (e) Townend, Proc. Roy.Soc., A 116, 637 (1927). (f) Landa, Comptes rendue, 186, 589 (1928). 4. Callendar and Mardles, Engineering, Feb. 4, 1927. 5. (a) Thompson and Hinshelwood, Prof.Roy.Soc., 125, 277 (1929). (b) Lenher, J .Am. Chem. Soc., 53, 3727 ( 1931). (c) Lenher, ibid., 53, 3752 "[1931). (d) Len.her, ibid., 54, 1830 (1932). (e) Hyman and Wagner,- ibid., 52, 4345 (1930). (f) Stevens, ibid., 50, 568 (1928). (g) Milas, J.Phys.Chem., 33 , 1204 (1 929) . 6. Young and Lucas, J.Am.Chem.Soc., 52, 1964 (1930). 7. Podbielniak, Ind.Eng.Chem., Anal.Ed.,~' 177 (1931). 8. Weston , ibid.,~' 179 (1 933) , 9. Brady, J,Chem.Soc.,, 1931, 756-9. 10. Riley . and Friend, ibid., 1932, 2342-4. 11. Mellor, "A Comprehensive Treatise on Inorganic and 1'heoretical Chemistry" Longmans Green + Co., London, 1927, Vol. I, p 951. 12, Ross Morris, Thesis, Calif. Inst. Tech,, Pasadena., 1932. 13. Pope, Dykstra and Edgar , J.Am.~hem.Soc., 51, 1875, 2203 , 2213 (1929), 14. Bone, J . Chem,Soc., !I.• 910 (1905). 15. Bone and Stocking, ibid., 85, 727 (1904), 16. Fry and Payne, J.Am.Chem.Soc., 53, 1973 (1931), 17. Engler, 8th Int,Congr,Appl.Chem., 25, 661 (1912).