The Reaction between Oxygen and 2-Butene Citation Morris, Ross Elliott (1932) The Reaction between Oxygen and 2-Butene. Master's thesis, California Institute of Technology. doi:10.7907/b8c7-6y32. https://resolver.caltech.edu/CaltechTHESIS:09112024-183709851 Abstract No abstract. Item Type: Thesis (Master's thesis) Subject Keywords: (Chemical Engineering) Degree Grantor: California Institute of Technology Division: Chemistry and Chemical Engineering Major Option: Chemical Engineering Thesis Availability: Public (worldwide access) Research Advisor(s): Unknown, Unknown Thesis Committee: Unknown, Unknown Defense Date: 1 January 1932 Record Number: CaltechTHESIS:09112024-183709851 Persistent URL: https://resolver.caltech.edu/CaltechTHESIS:09112024-183709851 DOI: 10.7907/b8c7-6y32 Default Usage Policy: No commercial reproduction, distribution, display or performance rights in this work are provided. ID Code: 16714 Collection: CaltechTHESIS Deposited By: Benjamin Perez Deposited On: 12 Sep 2024 19:05 Last Modified: 12 Sep 2024 19:12 Thesis Files PDF - Final Version See Usage Policy. 4MB Repository Staff Only: item control page

THE REACTION BETWEEN OXYGEN AND 2-BUTENE Thesis by R. E. Morris In partial fulfillment of the requirements f'or the degree of Master of Science CALIFORNIA INSTITUTE OF TECHNOLOGY Pasadena, California 1932 INTRODUCTION The oxidation of mono-olefin hydrocarbons has been a subject of study for many years. So far, only ethylene and propylene have been investiiated. Lenher {l) has done the most recent comprehensive work on both these compounds. He made a careful examination of the inter• mediate oxidation products and found, in the case of the slow thermal oxidation of ethylene in small Pyrex vessels~ formaldehyde, ethylene oxide, formic acid, glyoxal, the oxides of carbon, water and a substance supposed to be diGxy.methyl perexide. Evidence of the formation of hydroien peroxide was also iiven. In the case of the oxidation of propylene under similiar conditions, the reaction products were acetaldehyde, for.!llaldehyde, propionaldehyde, formic acid, acetic acid, carbon oxides, propylene oxide and a peroxide compound. It was shown that in the presence of oxyien the polymerization and pyrolysis of ethylene and propylene took place at lower temperatures than when the hydrocarbon was in the pure state. Lenher explained this by assuming the activation of the double bond by oxygen to be the primary process in the reaction. It was thouiht that a study of the oxidation of 2-butene .might help to clear up the mechanism of the -2- oxidation of the mono-olefin hydrocarbons in general. It would be of interest to know whether the intermediate products of this reaction were of the same type as those found by Lenher for similiar oxidations. EXPERIMENTAL The reaction was studied by the flow method at atmospheric pressure. The 2-butene was prepared by heating 100 cc. Eastman's l ~butanol No. 50 with 100 cc. 95% sulfuric acid and 50 cc. water in a three-liter three-neck flask provided with a reflux condenser and a safety tube. You!li and Lucas {2) have shown that l-butanol Wlen heated with 60% sulfuric acid {by 0 volume) at a temperature of 140-160 C decomposes to ~ive pure 2-butene. The &as was led from the top of the condenser throuih three spiral wash bottles, each of approximately 200 cc. capacity. The first spiral wash bottle contained a 50% potassium ,hydroxide solutio.n to remove traces of sulfur dioxide from the gas. The second and third wash bottles contained 40% sulfuric acid to absorb alcohol vapors. The i&S was then passed throuih a tower containing soda lime and -3- calciwn chloride to a trap, cooled by ice and cqncentrated hydrochloric acid, where it was condensed and stored. Before be~innin~ an experiment, the 2-butene was volatilized at room temperature and the gas run int0 a 2O-liter bottle displacini water. The proper amount of oxyien was then run in and the mixture of iases allowed to stand for a day. The mixture was analyzed at the end of this period. A small amount of nitro- ~en was always found to be present. Durini an experiment, water was forced from a second 2O-liter bottle into the first by gas pressure. The ' ias pressure was furnished by a tank of nitrogen and was adjusted with a diaphra~m valve. The mixture of oxygen and 2-butene was pushed out of the bottle and throu~h the apparatus at a constant rate by the entering water. The mixture of iases was led throuih a flowmeter and a calcium chloride tower into the reaction vessel. The reaction vessel consisted of a vertical Pyrex tube of 7 mm. internal dia.metero It was heated in a 30 cm. electric furnace, the temperature being determined with a Chromel-Alwnel thermocouple. The hot junction of the thermocouple was located i n a Pyrex tube adjacent to the reaction vessel at the center of the furnace. -4- The reaction products were cooled in a short water jacketed condenser and easily condensable substances removed in an ice trap. The gas was passed throu~h two spiral wash bottles to remove water soluble .material and then throuih a flowmeter. The ~as for analysis was drawn from the stream immediately after it left the flowmeter. All the experiments were made with an average gas velocity of 43 cc. per minute. The ma.x.imum. variations in this fi~ure were less than 10%. Assuming the entire lengt~ of the reaction vessel in the furnace to be up to the reaction temperature, the time of contact of the gas mixture was 16 seconds. In preliminary experiments it was found that at . 0 temperatures above 500 C, carbon was deposited on the walls of the reaction vessel and material suspended in the issuing gas caused trouble in the second flowmeter. This indicated that polymerization and pyrolysis were the principal reactions and not oxidation, so the remainder of the experiments were done at lower temperatures. The results of these experiments are given in Table l. All the gas analyses were done with an Orsat apparatus, using a hot copper oxide tube to determine hydrogen and carbon monoxide and a combustion pipette to determine the saturated hydrocarbons. Since in most of the experiments the saturated hydrocarbons were Table l Effect of Temperature on Reaction of Oxygen with 2-Butene Time of each Experiment. 100 minutes Rate of Flow. 43 CCo per minute Tempo oc Analysis Entering of Gases Condensate in CCo Aqueous Oil Phase Phase Rate of Flow Exhaust Gases cc. per mino Oz C4Hs Ni 380 3lol% 62.3% 606% 0.1- 38 396 34o0 64o3 lo7 Oo3 35 423 3a.,8 60.4 3.8 3.9 22 426 34.,8 60.7 4o5 3o3 22 452 34o0 64o3 1.7 3.0 22 47'1, 32.l 00o4 3306 63o0 490 ,; Tempo 7.5 lo5 208 28 3.4 lol 1.4 30 Analysis of Gaseous Products 00 ca. Hz co Cz~ 30o7% Ool% Oo3% Oo3% 607% 58.,6 3206 o.o lo2 lol 406 2o7 6008 llo3 OoO 15.,3 lo9 a.o 426 206 62o4 1408 Oo2 10 .. 4 lo4 802 412 lo5 .57o9 12o7 Oo2 1308 3o2 10o7 47'1 lo0 a4o9 10.,6 008 15o3 5.6 11.8 490 008 50o5 3.,5 2.0 25.0 l2o 3-l 5o9 Tempo Koles OG HCHO CO2 unsato Oz 380 Ool% 6108% 396 lo9 42~ l ?) Moles Total Aldehyde N'z ltoles Oxid.e Equivo Acid Equiv. Peroxide 380 000049 396 0.0419 423 000274 0.0395 0000013 0000329 426 0.0275 0.0434 0000064 0.00220 452 0.0240 0.0268 477 000179 0.0226 0000012 0.00085 0.00105 490 Oo0l82 0.0179 o.o 0000073 0.00099 10. 4% CH4 l. 9% C2 H6 0.0060 0000162 0000354 ( tt ) I Table l (contdo) Identification of 2,4-Dinitro Phenylhydrazones oc Derivatives Unidentified Derivatives Identified Tempo . 0 380 Aeetaldehyde mopol58.5 C Orange needles mopol55 °C Yellow plates m.pol5l-2 °C 396 Acetaldehyde m.p.l59-60 °C Propionaldehyde mopol50 °Q Orange crystals m.p.150 °0 Long red needles m.pol55 °G Yellow plates m.p.147-8 °C Orange crystals mopol42 °G 426 Acetaldehyde m.p.159-60 °C ,Propionalde.byde m.pol48-8a5 °C 452 Long red needles m.p.142 °0 Yellow plates m.p.l52.5 °C 477 - Note The melting points were taken by noting the melting point of individual crystals with the aid of a magnifying lense. Only in the case of the mixed melting points were the crystals crushed. The derivatives identified were verified by mixed melt~ ing points in all cases. The unidentified derivatives may be spatial isomers of those identified. The color of these crystals is not a distinguishing prqperty as the acetaldehyde derivative m.p.159-60 C has been prepared both as flat yellow plates and flat orange needles. Melting Points of 2 1 4-Dinitro Phenylhydrazones Formaldehyde 162-3.5 °0 Acetalde.byde l59.5-60o5 °C Propiona.ldehyde l50-5l°C n-Butyric aldehyde l22 °C Isobutyric aldehyde l82°C .¥ethyl ethyl ketone 115 °c present in very- a.mall quantities, their ex.act determination was impossible with the apparatus used, but i t could be shown thGt in all cases they consisted almost entirely of methane and ethane. The water in the spiral wash bottles always gave a ~ood iodoform ~est and a positive test for aldehydes with Schiff's rea~ent. The condensate consisted 0 of one phase at temperatures below about 455 c. At higher temperatures the condensate consisted of two ~hases. The upper phase was a yellow oil. density ca. 0.9. It had a very penetrating odor, boiled over a ran~e of 75 -185° C leaving a residue of tar in the distilling flask, and very rapidly decolorized a solution of bromine in carbon tetrachloride. lower phase consisted mainly of water. The When diluted with more water, a small quantity of light yellow oil separated. This aqueous phase gave a good iodoform test and reacted acid to litmus. It gave a positive test for hydroien peroxide with a solution of titanium tetrachloride in dilute hydrochloric acid {3) and a positive test for formic acid when heated with powdered mercuric oxide (4a). It gave a positive teat for an olefin oxide when added to a saturated solution of manganous chloride (4b). Tp.e aqueous phase increa.s~'d. in acidity when left sta.ndin~ at room temperature. In some cases a constant slow evolution of gas was noted. but it was -6- formed in such small quantities that it could not be identified. This is analogous to the phenomenon ob- served by Lenher {l). He explained it by assuming the presence of dioxymethyl peroxide, CH 2 0HOOCH 2 0H, W1ich decomposes to ~ive hydrogen and formic acid {5). CH 2 0HOOCH 2 0H - H2 + 2HCOOH The formaldehyde was determined by the cyanide method {6). This method has ·been found to be good in the presence of acetone, paraldebyde and acetaldehyde; but for these experiments its correctness is questional>le. This will be discussed further when the iden- tification of the carbonyl compounds formed is taken up. The total aldehyde present was determined by the bisulfite method {7). Both in the determination of for.ma.ldebyde and total aldehyde, aliquot portions were ta.ken of the aqueous phase of the condensate and of the wash water. The acid present in the aqueous phase of the condensate was determined by titrating an aliquot portion with O.ln. NaOH. Durins this titration the solution was cooled by ice to decrease the r &te of decomposition of the peroxide. Even with these pre- cautions, the end point shifted slowly. • An excess of O.ln. NaOH was then added to the solation and the .mixture left standing for about four days at l0° C to decompose the peroxide. At the end of this period, the peroxide was determined by titrating to -7neutrality with O.ln. HCl. The moles of peroxide were equivalent to one-half the difference between the moles excess alKali added and the moles acid used in this titration. To determine the olefin oxide.an excess of solid manganous chloride was diss olved in the solution . and the mixture left standing at room temperature for about ten days. The reaction of an olefin oxide with manganous chloide is R ~ H-C-OH I H-C, , CI 2-He O + 2. ~~;-o F{ R The precipitated manianous .hydroxide was determined by titration with O.ln. HCl. In all these titrationa, phenol red, pH ran&e 6.8-8.4, was used as the indicator. For identifying the c~rbonyl compounds present in the wash water, 2,4-dinitro phenyl.hydrazine was used (8). A 3% sulfuric acid solution was saturated with this reaient and added in excess to a quantity of the wash water. In all cases a voluminous yellow precipitate of the 2,4-dinitro phenyl.hydrazones was formed after a few minutes. This precipitate was collected, dried and the components separated by fractional crystallizati0n from alcohol o The derivatives of acetalde.hyde and propionalde.hyde were separated in a pure state by this method. These compounds were identified both by microscopic comparison of the crystals with crystals of the pure substance and by mixed meltini points. The acetaldehyde was present in much t h e laq,er quantity. NG> evidence was found for the -8- presence of formaldehyde, methyl ethyl ketone, or ilyoxal in the wash water. The fact that formaldehyde could not oe shown to be present places the determinations of formaldehyde given above open to question. No explanation can be ~iven for this iontradiction. Olefin oxides tend to rearrange to carbonyl compounds at hiih temperatures (9). If butylene oxide were present, the existence of some methyl ethyl ketone in the wash water would be expected. This could not be shown to be true; perhaps, because of the small quantity present. DISCUSSION From Table l i t can be seen that reaction between oxygen and 2-butene is just beiinning to take place at 380 °0 with the time of contact used. The reaction has not increased much between 380°C and 396 °C, but between 396 °0 and 423°0 a much larger increase is evident. The yield of reaction products in the condensate appears to have reached a maximwn somewhere within this latter range. The determination of the oxide, acid and peroxide could not be .made at the lower temperatures because the condensate was ne~ligible. -9- As the ameunt of intermediate oxidation products decreased, the amount of polymerization and pyrolysis increased. This is shown by the appearance of an oil phase in the condensate and an increase in the unsaturated gases in the product. The increase in the 0 0 unsaturated ~ases appeared between 462 C and 477 C and is shown by Table 2. Table 2 Temperature 0 C cc. of unsat. gas per min. in product 380 3.E 21:::;"".6 396 20.5 423 13.4 426 13.7 462 12.8 477 15.4 490 16.2 The second coltunn of Table 2 was calculated by multi-plyins the fraction of unsaturated gas in the product by the rate of flow of the exhaust iaS in cc. per minute. The experiment was made of passing pure 2-butene 0 throuih the Pyrex tube at 486 C and it was found that the formation of condensable polymerization products was neili~ible. Wheeler and Wood (10) passed pure 2-butene throuih a quartz tube at 600° C and found 35% of the iaS to have decomposed or polymerized. -10- The formation of decompositien and polymerization products at temperatures below 500° C, as shown by the increase of unsaturates in the iaseous product and the appearance of an oil phase in the condensate, indicates that oxygen must facilitate these reactions. The best explanation for this is the one given by Lenher (1) to explain a similiar phenomenon in the case of the reaction between ethylene and oxygen. He assumed that the c=c bond is activated or opened up by oxygen. CH3 I HC HC <;=H3 + Oz ---+ I ·~ CH 3 I HC Cti I HC.:,o-o H~,,,,,, CH3 HY)o-o . yH3 ~ HCI H~~ + Oz CH 3 I HCl The butylidene and ethylidene residues i-oay react with 2-bute.ne molecules to give higher mono-olefins. No analysis was made of the unsaturated portion of the gaseous product -11- or of the oil phase in the condensate so no definite statement can be .ma.de as to the particular compounds for.med. The reaction between oxygen and 2-butene seems tQ follow two paths. The first is the oxidation at the double bond to form acetalde.hyde. CH 3CH::CHC1¼ + Ol - 2 CH 3 CHO This probably predominate s at the lower temperatures. The second is the formation of the addition complex as discussed above. Some of the acetalde.hyde for.med in the above manner is decomposed by thermal means . • CH 3 CHO - CH_. -t- CO This accounts for the presence of .methane in the gaseous product. Undoubtedly some of the acetalde.hyde reacts with oxy~en. Bone and Stockings (11) found that acetaldehyde reacts with oxygen at 450°C to give carbon monoxide, .methane and .hydrogen, along with some formaldehyde o A part of the acetaldehyde reacts with .hydrogen peroxide to form the peroxide compound, probably dioxyethyl peroxideo ~H3 H-C II 0 + ~H OH The hydrogen peroxide is formed by the reaction between the addition complex and water. -12- + The addition complex may also react with a molecule of 2-butene to iive butylene oxide. H¢H3 Hf~ ~Ha H..s .H . + H ~I CH3 ~ 2 H<;, HC)) I CH3 The oxide probably rearranies to give methyl ethyl ~etone which on oxidation gives propionaldehyde and formic acid. CH 3 CHzCOCH3 + q~ -+ CH 3 CH z.CHO + HCOOH The ethane in the gaseous product is formed by the ther.aia.l decomposition of the propionaldehyde. The various reactions and phenomena in the oxidation of Z-butene can perhaps best be considered by a schematic representation of the course of the whole reaction. This scheme accounts for all the observed products of reaction and their formation in a stepwise sequence of consecutive reactions. The Re action between 2-Butene and Oxygen direct thermal • oxi dati 0n decomp. _ _ _ _ _...,. 20H CHO - - - - -Cf\+ CO 3 Addition Complex 2 9~ Hl"o Dioxyethyl Pero ide HQ/ CH3 Butylene Oxide dec ,mp. rear raJement l 0H3 0H2 0OCH3 Iviethyl Ethyl . YH2O + CO2 HOO OH~ dec-0mp. ~ C01 + Hz SID.WARY The slow thermal oxidation of 2-butene was studied 0 in sniall Pyrex vessels over a temperature range 380-490 c. The principal reaction product was acetaldebydeo Other products were propionaldebyde, formic acid, an olefin oxide, hydrogen peroxide, an organic peroxide, the oxides of carbon and water. At tempe~atures above 0 450 C, the polymerization and decomposition of 2-butene ·b ecame an import~,nt reaction. A scheme 01 the mechanism of the oxidation of 2-butene has been outlined. The activation of 2-butene, probably by the formation of an addition complex, is used to explain the formation of the olefin oxide and the polymerization at low temperatures. -14- REFERENCES {l} Lenher, J. AIIJ.. Chem. Soc.,~. 3737, 3752 {1931); .2,!, 1830 (1932). (2) Young aid Lucas, J. Am. Chem. Soc., g, 1964 (1930) {3) MellQr, "A Comprehensive Treatise on Inorganic and Theoretical Chemistry," Longmans, Green and Co •• London 1927, Vol.I, p. 951 {4) Mulliken, "Identification of Pure Organic Compounds, It John Wiley and Sons, Inc., New York, 1905 I {a) Vol. I, P• 83. (b) Vol. I• p. 160. (5) Leiler, Ann., 217, 381 (1883). Chem. Zentr .• 1604 (1888). Nef, Ann.,~. 202 (1897) Baeyer, Ber.,~. 2479 {1900). (6) Romijn, z. anal. Chem., -22,, 18 (1897). Smith, J. Am. Chem. Soc.,~. 1028 (1903). Williams, ibid., _ll, 596 (1905). (7) Ripper, Monatsh. Chem., 21, 1079 (1900) Langedyk, Rec. Trav. Chim.f i§., 218 (1927) {8) Allen, J. Am. Chem. Soc.,~. 2955 (1930) {9) Hec~ert and Mack, J. Am. Chem. Soc., -2!, 2706 (1929) (10) Wheeler and Wood, J. Chem. Soc., 1819 (1930) (11) B~ne and Stockings, Trans. Chem. Sec., 710 (1904)