Патент USA US3082256код для вставки
United States Patent 0 3,082,246 Patented Mar. 19, 1963 2 1 effectively suppresses the undesirable polymerization of 3,082,246 the ole?n, does not favor the formation of secondary and primary esters and can be readily separated from the Inc, New York, N.Y., a corporation of Delaware ester product without decomposition of said product. In a typical operation of my novel process the tertiary PREPARATION OF TERTIARY ESTERS _ Harry Chafetz, Poughkeepsie, N.Y., assignor to Texaco No Drawing. Filed Feb. 17, 1960, Scr. No. 9,162 7 Claims. (Cl. 260-—497) ole?n is contacted with a carboxylic acid in a mol ratio of between about 1:10 and 10:1, preferably between about 1:4 and 4:1, at a temperature between about 135 and 350° 'F., preferably between about 150 and 225 ° F. the preparation of carboxylic acid esters of tertiary alco hol and, more particularly, to such a process where a 10 and under a pressure between about 50 and 2000 p.s.i.g., preferably between about 100 and 300 p.s.i.g. in the pres “tertiary base” or, more simply, a “tertiary ole?nic com ence of between about 0.5 and 20 mol percent sulfur pound” is reacted in an esteri?cation Zone with a car The instant invention relates to a catalytic process for ‘dioxide, preferably between about 1 and 10 mol percent, boxylic acid employing sulfur dioxide as the catalyst. Using, for example, acetic acid and the hydrocarbon isobutylene, the reaction can be represented as follows: 15 011300013 + 04113 2* CHgCOOCrHg Acetic acid Isa‘ butylene be thoroughly mixed prior to or during the reaction period in order to insure high yields of ester product. Tertiary-bury] acetate Such ester is useful as a paint solvent and as a grease component. 20 In addition, it is a valuable additive for improving the octane rating of high quality leaded gaso line. based on the total mols of said ole?n and acid. The novel process is operative whether the reactants and catalyst be in the liquid phase or in a liquid-vapor phase equilibrium. In any case, it is desirable that they As a group these esters are solvents for many The process can be either continuous or batch. If a continous operation is employed, it is desirable to admix the reactants and catalysts with one another prior to their exposure to the reaction zone. In such a system the ad mixture can be fed into the reaction zone at temperatures organic materials and, therefore, are useful as vehicles 25 less than are found in the’major portion of said zone and ‘therefor. The condensing of a tertiary ole?nic compound with a then allowed to reach the reaction temperature autog enously by exothermic heat of reaction. Alternatively, carb-oxylic acid is usually done in the presence of a cata lyst. Some of the catalysts employed in the past were sul indirect reactor cooling or heating can be used. In a con tinuous process the reaction mixture is continuously with furic acid, complexes of boron trifluoride, orthophos phoric acid suitably supported on an inert support such as drawn from the'reaction zone. The components compris kieselguhr, benzenesulfonic acid, alkyl sulfates, or other ing the Withdrawn stream can be separated from one an other by any standard means such as fractionation. For mally present as a distinct liquid phase in the esteri?ca economc purposes it is desirable to recycle the sulfur dioxide and 'unreacted reactants to the reaction zone. tion reaction mixture, or are homogeneous therewith, My novel process may also be a batch or a combination or are sorbed on a solid porous carrier such as silica, 35 of a batch or continuous process. In the latter, the re charcoal or alumina. strong mineral or organic acids. Such catalysts are nor In the condensation of a tertiary ole?n compound with a carboxylic acid to ‘form a tertiary ester there is a serious competing reaction, namely, that of polymer formation from the tertiary ole?nic material.v The esteri?cation re-~ 40 action involving tertiary ole?ns is far more sensitive to' polymer competition than is the corresponding reaction actants, catalyst and formed products are passed through the reaction zone and continuously recycled therethrough with batch ‘or incremental withdrawal of the reaction mix ture‘ for the separation ‘of the ester product therefrom and the subsequent return of the catalyst and unreacted reactants to the circulating reaction system. involving a secondary ole?n or a primary ole?n. Actu ally, when secondary ole?ns such as butene-2 are con Corrosion resistant reaction vessels are in order, e.g. ones of austenitic stainless steel, high chrome stainless densed with carboxylic acids, it is conventional to rid 45 steel and the like because of the possible corrosive tend the hydrocarbon feed of “tertiary ole?ns” by causing them encies of the carboxylic acid reaction in the process. to polymerize, then to operate with the remaining sec By the ‘term “tertiary ole?nic hydrocarbon,” I intend a hydrocarbon'containing at least one tertiary ole?nic ondary ole?n containing feed. By means of our process hydrocarbon streams can be freed of tertiary ole?ns with carbon. The useful ole?nic starting materials for my out signi?cant polymerization to make a valuable ester 50 process have at least ‘one side chain branching from an product e?iciently and the so-treated unreacted- hydrocar-q ole?nic carbon ‘atom (including anlole?nic carbon atom bons separated from the ester for other use. in a cyclic structure). Speci?c examples of suitable ole An advantage of our process over conventional proc ?nic hydrocarbons for use in my process include isobutyl essing of tertiary ole?nic compounds for the tertiary ester, ene, 2-methyl-l-butene, 2-methyl-2~butene, 3-ethyl-3lhep formation is the effect of suppressing the polymerization 55 tene, 2,3-dimethyl-3-decene and l-rnethyl-l-cyclohexene. of these ole?ns while esterifying at temperatures up to about 350° F. A further advantage of our process over‘ ability the aliphatic C4_12 tertiary monoole?nic hydrocar conventional treatment is it permits the separation of the ester product from the reaction mixture by heat treatment bons are the most desirable for my process. The ole?ns can be pure, mixed with each other or mixed As a practical limitation because of the cost and avail methods such as distillation without undesirable decom 60 with unreactive or substantially less reactive materials. position of the ester product. Distillation or other heat Thus, ‘for example, we can use pure isobutylene made by treatments of the crude ester product in the presence of crackingan isobutylene dimer. On the other hand, we strong acids such as sulfuric acid, phosphoric acid, sul can use a C, and/or a C5 cut ‘from a catalytic or a thermal fonic acid, hydrochloric acid and the like even in the cracking operation, which would ordinarily contain some presence of an extremely small amount of said acids 65 what less than 20% of the tertiary ole?n and the balance usually results in the rapid breakdown of the ester. > of other diluent hydrocarbons. A typical so-cal-led “B-B” stream from catalytic cracking can contain 10'—25 In accordance with the foregoing, I have discovered mol percent isobuty-lene, 50 mol percent para?‘ins and that sulfur dioxide is extremely effective in catalyzing the reaction between a tertiary ole?nic compound and a car 70 the balance preponderantly butene-l, and cis- and trans butene-Z. A suitable stream for making tertiary-butyl boxylic acid to form the corresponding tertiary ester. In carboxylic acid esters is a stream containing about 25 addition, I have discovered that the sulfur dioxide catalyst product. 3,082,246 4. 3 In runs Nos.‘ 550 and ‘562 found in Table B the tertiary butyl acetate was recovered from the withdrawn reaction mol percent butylenes and the balance predominantly ‘ normal butane. Other ole?ns which ‘may be employed in my process are the polyole?ns such ‘as 2,4-dimethyl-2,4-hexadiene and Also suitable are oxygenated aliphatic hydro isoprene. carbon compounds of tertiary base ole?nic carbon con ?guration, e.g., alkyl vinyl ethers such as ethyl or methyl vinyl ether. Conceivably, the tertiary base ole?n com mixture utilizing the following procedures: Atiary phosphate‘or phosphate radical or an aromatic such tiary butyl acetate. Run No. 550.—One=part of the liquid reaction mixture removed from the batch reactor was mixed with 2.5 parts of water and 2.1 parts of ether. The resulting or ganic layer was separated ‘from the aqueous layer and washed with 2 parts of 10% aqueous sodium hydroxide, dried over anhydrous potassium carbonate and distilled. pound can be onewherein oneor more hydrogen atoms are substituted with an inert substituent such as halogen 10 The ‘fraction recovered at a distillation temperature of between 201 and 207° 'F. at 1 atm. was identi?ed as ter (e.g. chlorine), an alkoxy radical, 'a nitro group, a ter Run N0. 562.-0ne part of the ?nal reaction mixture was removed ‘from the batch reactor and mixed with 2.1 parts of triisobutylene, 1 part of crushed ice and 1.8 parts as a phenyl group. The particular carboxylic acid used is dictated by the particular product‘ desired. Because the presence of water in the esteri?c‘ation‘reactor induces a competing reaction, 'of’potassiurn carbonate. The resultant mixture foamed ‘ and after the foaming had ceased the organic layer was namely, one wherein tertiary valcohols are made, the re actions should be virtually anhydrous for best results to make the ester exclusive. Thus, for example, when ace separated from the aqueous layer, washed with 1 part pure) should be used. tertiary butyl acetate. of water, dried over anhydrous calcium sulfate and dis tates are made exclusively, glacial’acetic acid (99.5% 20 tilled. The ‘fraction recovered at a distillation tempera ture between 201 and 207° F. at 1 atm. was identi?ed as The car-boxylic acid reactants can be fatty acids suit ably in the range from formic to stearic acids and advan In Table A below are found the reaction data for the tageously C1~C8 faty acids. Alternatively, they can be conversion of isobutylene in admixture with one or more acids such as malonic, oxalic and so on suitably up to Table A polybasic, e.g. saturated aliphatic hydrocarbon dibasic 25 C; hydrocarbons. sebacic or even higher. They can have inert nuclear substituents for hydrogen atoms (such as keto, nitro, Run No. halogen, alkoxy tertiary phosphate, etc.). They can have 572 an aromatic nucleus such as benzoic, phthalic, toluic or 30 the like. Reaction Ingredients: Typical of the carboxylic acids which can be employed in the condensation with ole?ns contemplated herein in 573 Hydrocarbon Reactant, Mol— Isobutylene-.. ,clude the following: acetic, malonic, propionic, butyric, isobutyric, valeric, isovaleric, acetone dicarboxylic, 2 35 ethyl hexanoic, benzoic, caproic, octanoic, ‘formic, oxalic, monochloroacetic and cyclohexane carboxylic. H 585 enacts» Sulfur dioxide, M01 M01 percent of SO, based on total acid and The reaction can be conducted in the presence of an hydrocarbon reactant ....................... -_ inert’ vehicle, e.g. ether, benzene, toluene or the like. 40 Such a technique can be useful ‘for dissolving one or both reactants. ' Wt. percent of SO, based on total acid and hy drocarbon reactant ......................... _ Reaction Conditions: Temp., "F .................................... -_ Time, Hrs ...... __ Pressure, p.s.i.g ............................... -. The subsequent example shows ways 'in' which my in Products, mol percent yield 1: vention has been practiced but should not be construed t-butyl acetate .... ._ see-butyl acetate as limiting the invention. 45 diisobutylene 2. 5 ‘Ea a o0c1»;m _ Products, wt. percenfyicld EXAMPLE I t-butyl acetate sec-butyl acetate In all runs reported in subsequent Tables A and B the dilsobutylene ................................. .. following procedure was employed: The isobutylene or C4 fraction containing isobutylene, 50 acetic acid and sulfur dioxide were introduced into a one gallon enclosed stainless steel batch reactor ?tted with an agitator, thermometer, pressure gauge, heat exchange coils, and valved entrances and exits.‘ The mixture was stirred from 1/2 to 4 hours‘and at the close of that period, the reaction mass was cooled to room temperature. 1 Based on isobutylene charge. 2 Mols diisobutylene formed/Mols isobutylene charged. As can be seen from the above, little or no polymeriza tion takes place With sulfur dioxide as the catalyst. In addition, there is shown that S02 selectively forms terti ary-butyl esters to the substantial exclusion of secondary butyl esters. In Table B below, are found data concerning the con version of isobutylene to tertiary-butyl acetate, the iso~ The pressure in the batch reactor was reacted to atmos pheric and the liquid remaining therein was withdrawn. The withdrawn liquid was analyzed by mass spectrometry. butylene being the only hydrocarbon present. Table B Yield Run No. Mol Ratio, GRID/acetic acld 571 ____ ._ 1/2 567B_.-- 1/2 583 ____ -_ 582 ____ ._ 550 ____ __ 562 ____ .. 111. 07 1/3. 44 4/1 4/1 80:, M01 S02. Wt. Percent of Total Reactants Percent of Total Reactants Temp., ‘’ F. Pres. p.s.l.g. React. Time, hrs. t-butyl acetate. t~butyl Dilsobu aoetute. tylcne, wt mol per- wt. pcr- cent 1 cent 1 percentI 5 5. 4 175 115 4 31 64 0. 3 5 5. 4 200 140 3 47 97 O. 8 3. 9 5.6 10 10 4. 3 6.1 11.3 11.3 250 200 250 300 300 155 360 500 2. 5 4 4 4 29 54 41 31 60 111 79 60 1.2 0.9 0. 4 1. 0 1 Based on isobutylene reactant. 3,082,246 5 6 The data in above Table B shows the effectiveness of Products, mol percent yield 1 my method in converting isobutylene into tertiary butyl acetate while at the same time desirably producing only a minimum amount of polymerization product. t-Butyl acetate ________________________ __ 1.5 Diisobutylene 0 ________________________ __ Products, wt. percent yield 1 EXAMPLE III The procedure of this example is comparable to the procedure of Example I with the exception that sulfuric acid was substituted for the sulfur dioxide catalyst. The t-Butyl acetate _______________________ __ Diisobutylene ________________________ __ 3.1 0 1 Based on isobutylene reactant. As can be seen by comparing the yield of the above liquid product was analyzed by mass spectrometry. The 10 run No. 588 with those of Tables A and B, the presence reaction data and results are reported below in Table C. Table C Reactants and catalysts, mol: Isobutylene of sulfur dioxide in applicant’s process is necessary to produce a tertiary ester in signi?cant quantities. All percentages, parts and ratios herebefore and here Run No. 600 __ 1 Acetic acid ___________________________ __ Sulfuric acid _________________________ __ 2 0.9 after recited are based on weight unless otherwise stated. 15 departing from the spirit and scope thereof and therefore only such limitations should be imposed as are indicated M01 percent of H2804 based on total mols of acetic acid and isobutylene ___________ __ 3 in the appended claims. Wt. percent of H2804 based on total weight of acetic acid and isobutylene ___________ __ I claim: 1. In a process for the condensation of an aliphatic 5 Reaction conditions: tertiary monoole?nic hydrocarbon of 4 to 12 carbon Temp., ° F. __________________________ ___ 130 Pressure, p.s.i.g _______________________ __ 1 28 13 Products, wt. percent yield 1 t-Butyl acetate ________________________ .._. 58 Diisobutylene 26 ________________________ __ atoms with a carboxylic acid selected from the group con 60 Time, hrs. Products, mol percent yields 1 t-Butyl acetate ________________________ __ Diisobutylene 2 _______________________ __ Obviously, many modi?cations and variations of the invention as hereinbefore set forth may be made without 1 Based on isobutylene reactant. 9 Mols diisobutylene formed/mols isobutylene charged. 25 sisting of a monobasic fatty acid, saturated aliphatic hydro carbon dibasic acid, aryl monocarboxylic acid and alkaryl monocarboxylic acid to form the corresponding tertiary ester in the reaction zone, the improvement which com prises: contacting said monoole?nic hydrocarbon with said acid at an elevated temperature and pressure in the 30 presence of sulfur dioxide. 2. A method in accordance with claim 1 wherein said pressure is between about 50 and 2000 p.s.i.g, said tem perature is between about 135 and 350° F., said hydro As can be seen by comparing the yields of diisobutylene carbon and said acid are in a mol ratio between about 1:10 of Table C with those of Tables A and B, the replace 35 and 10:1 and said sulfur dioxide is present in a mol ment of sulfur dioxide with a sulfuric acid catalyst results percent between 0.5 and 20 based on the total mols of reactants. in the undesirable production of substantially larger quan tities of polymerized product even at a reduced tempera 3. A method in accordance with claim 1 wherein said ture. pressure is between about 100 and 300 p.s.i.g, said tem EXAMPLE III 40 perature is between about 150 and 225° F., said hydro carbon and said acid are in a mol ratio between about 1:4 The procedure of this example is the same as the and 4:1 and said sulfur dioxide is present in a mol percent procedure of Example I with the exception that catalyst was not employed and the reactor was pressured with between 1 and 10 based on the total mols of reactants. 4. A method in accordance with claim 1 wherein said nitrogen to the indicated pressure. The liquid product ' was analyzed by mass spectrometry. The reaction data 45 hydrocarbon is isobutylene. 5. A method in accordance with claim 1 wherein said hydrocarbon is in admixture with at least one other hydro carbon having 4 carbon atoms. 6. A method in accordance with claim 1 wherein said Reactants and catalysts, mol: Run No. 588 50 acid is a monobasic fatty acid having from 1 to 8 carbon Isobutylene __________________________ __ 3 atoms. Acetic acid 6 7. A method in accordance with claim 6 wherein said Reaction conditions: ’ acid is acetic acid. Temp., ° F. ___ 200 and results are found below in Table D. Table D ‘Pressure, p.s.i.g _______________________ __ 600 Time, hrs. 6 No references cited.