Rudo-At-Thur a 77OAPAVA 1S Patented Dec
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Dec. 11, 1951 J. E. MAHAN ET AL 2,578,565 HYDROGENATING SULFOLENES TO SULFOLANES Filed Dec. 28, 1948 o g X g t 92.9 DVOS a dig NGOOOH Ofse INVENTORS J.E. MAHAN BY S.C. FAUSKE Rudo-at-thur A 77OAPAVA 1S Patented Dec. 11, 1951 2,578,565 UNITED STATES PATENT OFFICE 2,578,565 HYDROGENATING SULFOLENESTO SULFOLANES John E. Mahan and Sig C. Fauske, Bartlesville, Okla., assignors to Phillips Petroleum Company, a corporation of Delaware Application December 28, 1948, Serial No. 67,745 15 Claims. (CI. 260-332.1) 1. 2 This invention relates to the production of the generic term “a sulfolane' or "a Sulfolane Sulfolanes by the hydrogenation of the corre compound' covering not only the above Com sponding unsaturated Sulfolenes. In One par pound but also the substituted derivatives there ticular embodiment it relates to an improved of, particularly those in which various radicals process for the production of 2,3,4,5-tetrahy mentioned in the preceding paragraph are Sub drothiophene-1,1-dioxide, commercially known stituted for one or more of the hydrogen atoms as sulfolane, by the catalytic hydrogenation of of the above structure. Where such a radical the corresponding unsaturated cyclic butadiene is hydrogenatable under the conditions of our monosulfone, i. e. 2,5-dihydrothiophene-1,1- process, it will be understood that the sulfolane dioxide, commercially known as Sulfolene, in the 0. containing the hydrogenated radical is included presence of a novel solvent. when reference is made to a sulfolane compound The term “a sulfolene compound' as employed which “corresponds' to a given sulfolene com herein and in the appended claims, defines ge pound. Thus, an alkyl Sulfolane, Such as a nerically the unsubstituted and Substituted un propyl or butyl sulfolane, corresponds to the al Saturated compounds comprising or containing 5 kenyl, such as allyl or butenyl respectively, Sul a sulfolene nucleus, i. e. a five-membered ring foLee. of four carbon atoms and a sulfur atom, a sin The material known as sulfolane, i. e. 2,3,4,5- gle olefinic linkage between any two adjacent tetrahydrothiophene-1,1-dioxide, has found val carbon atoms of Said ring, and two oxygen luable uses as an intermediate in the produc atoms each of which is directly attached to the 20 tion of other useful organic chemicals, and as sulfur atom thereof. The generic term “a sul a selective solvent for hydrocarbons of various folene' or "a sulfolene compound,' therefore types, fatty acids or fatty acid esters, and the covers the simple unsubstituted sulfolenes, like. Various derivatives thereof have also been viz. the 3-sulfolene having the general struc likewise employed, particularly 2,4-dimethyl ture 25 sulfolane, which has been used as a selective HCasas CE solvent to separate aromatic hydrocarbons from Hé ch, petroleum fractions. A convenient type of raw Ys/ material for the preparation of these various 2 Sa sulfolene compounds is found in the conjugated 2 n. O 30 diolefins, which are readily converted by reac and the 2-sulfolene having the structure tion with sulfur dioxide in known manner to unsaturated cyclic sulfones or sulfolenes. Thus, IC-CI 2-methyl-1,3-pentadiene by reaction with Sull H. &H, fur dioxide forms 2,4-dimethyl-3-sulfolene, N s^ 35 which may then be hydrogenated to the cor of2 SaSo responding sulfolane. This is true of the various unsubstituted and substituted aliphatic conju as well as the various substituted derivatives gated diolefins, such as those ranging up to 12 thereof, i.e. sulfolene compounds in which war carbon atoms per molecule. Similarly bu ious organic and/or inorganic and particularly 40 tadiene is reacted with Sulfur dioxide to form hydrocarbon radicals, i. e. alkyl, alkenyl, aryl, the cyclic butadiene Sulfone (Sulfolene) which aralkyl, alkaryl, allicyclic and/or heterocyclic is convertible by hydrogenation to sulfolane. radicals, and/or such inorganic radicals as do However since butadiene cyclic Sulfone is a Solid not interfere with the hydrogenation reaction, at room temperature, its hydrogenation to Sul are substituted for one or more of the hydro 45 gen atoms of the above unsubstituted Sulfolenes, foane must be carried out either in the presence provided the total molecule contains not over of a Suitable Solvent or at temperatures above twelve carbon atoms. its melting point. As practiced in the past, both Similarly, the term “a sulfoliane compound' of these processes have disadvantages which referS to a Saturated Sulfolene compound. In 50 make them undesirable. When operating in a other words, the sulfoliane compound contains Solvent medium according to methods of the Or consists of a saturated five-membered ring prior art recovery of catalyst, solvent, and prod of four carbon atoms and a sulfur atom, the uct are necessary and time consuming opera latter having two oxygen atoms directly at tions. The catalyst is usually removed from the tached thereto. The structural formula of the System by filtration after which the solution is 55 fractionated to separate the Solvent from the re simple unsubstituted sulfolane, therefore, is action product. This necessitates the use of ex H2C-CH pensive fractionation equipment and greatly ex tends the probability of handling losses. When H N oil, 80 pure butadiene cyclic sulfone is hydrogenated 2’s2 n. in the absence of a Solvent medium at temper O O atures aboves its melting point with the usual 2,578,565 3 4. hydrogenation catalysts, hydrogen absorption tageous to effect the hydrogenation reaction at is normally incomplete. This proceSS also has this latter temperature. It may be pointed out several disadvantages such as low yields, quick that use of a sulfolane compound as Solvent for catalyst poisoning, and decomposition of reac its corresponding sulfolene is advantageous even tants as evidenced by the pronounced odor of when hydrogenating at temperatures above the Sulfur dioxide in the reactor effluent. Similar meiting point of the sulfolene, in that reduced considerations are involved in the hydrogena catalyst poisoning and/or more complete con tion of the Substituted Suifoleines. version is often obtained as compared With hy It is an object of this invention to produce drogenation of the sulfolene alone, and there sulfolane compounds by an in proved inlethod is no necessity of distilling off an extraneous of hydrogenating the corresponding sulfolenes. solvent from the reactor effluents. The inven A further object is to obtain practically theo tion in its broadest aspects may be practiced retical yields of Sulfolane in the hydrogeiation at any temperature at which decomposition is of sulfolene. Yet another object is to minimize not so excessive as to stop the hydrogenation or prevent decomposition of Sulfolene compounds short of an economic yield, though of course it during catalytic hydrogenation thereof. An is preferred to avoid any decomposition, which other object is to avoid the necessity of remov is readily done in using the Sulfolane as the ing a Solvent by distillation from a Sulfolane Solvent. product obtained by hydrogenation of a sulfolene Any cf the more active hydrogenation cata in a Solvent. Yet another object is to reduce 20 lysts may be employed in our process. For eco greatly the amount of material which must be nomic reasons however we have preferred to filtered to remove a suspended catalyst from the use the more active base metal catalystS Such effluent of a Sulfolene hydrogenation reaction. as nickel, cobalt, chromium, copper-chronium Further objects and advantages of the inven oxide, and the like. These may be used ini. tion Will be apparent, to one skilled in the art, finely divided form such as, for example, Rafiey from the accompanying disclosure and discus nickel, or may be suitably supported on kiesel S.O. guhr, aluminum oxide, diatomaceous earth, and We have now found that many advantages the like. A supported catalyst in pelleted form and greatly improved results may be obtained which we have found satisfactory comprises 70 in hydrogenations of the type described by first 30 to 80 per cent nickel on diatonnaceous earth. dissolving the Sulfolene to be hydrogenated, not It is an advantage of our process that rio Sol in an extraneous solvent as has heretofore been vent recovery steps are necessary and no catalyst done in the prior art, but rather in the corre poisoning is observed. It is a further advantage Sponding Sulfoliane as a solvent. As applied of our process that relatively mild conditions Specifically to the hydrogenation of butadiene of operation provide substantially complete hy Cyclic Sulfone, a significant feature of our proc drogenation with little, if any, loss resulting from eSS lies in the high solvent power of the solvent decomposition. It is still a further advaitage employed, namely sulfolane, for the sulfolene. of our method that the product is ready for We have found that two parts by weight of shipment or immediate use as it flows from the Sulfolane will dissolve about three parts by ...) process. These and other advantages of the in Weight of Sulfolene at room temperature (30° vention will be further apparent from a descrip C.). This is advantageous in that larger tion of the accompanying drawing in which is amountS of the butadiene cyclic sulfone are shown diagrammatically one form of apparatus processed per unit equipment capacity when in which our process can be carried out. The using Sulfolane as an initially present solvent -i. 5 invention will be illustrated by Specific refei' than With other, formerly used solvents of lower ence to the hydrogenation of the simple but3 Solvent power. Additionally, as will be shown diene cyclic monosulfone known as sulfolene (3- hereinafter, the extent of conversion and the sulfolene) to form sulfolane, but the invention, maintenance of catalytic activity are remarkably is readily adapted to the various substituted improved by the practice of our invention.