United States Patent (19) (11) 3,872,165 Schenk et al. (45) Mar. 18, 1975 54) MANUFACTURE OF WINYL SULFONATES AND WINYLSULFONIC ACID FROM 58 Field of Search................................. 260/513 R CARBYL SULFATE (56) References Cited (75) Inventors: Walter Schenk, Bad Duerkheim; UNITED STATES PATENTS Roland Dahlinger, Neckargemuend; 3,255,240 6/1966 Wolfram et al................. 260/513 R Dieter Stockburger, Gruenstadt, all of Germany OTHER PUBLICATIONS 73) Assignee: Badische Anilin- & Soda-Fabrik Breslow et al., V. Am. Chem. Soc. 79, 5000-5002 Aktiengesellschaft, (1957). Ludwigshafen Rhine, Germany Primary Examiner-Leon Zitver (22) Filed: Nov. 30, 1971 Assistant Examiner-Nicky Chan Attorney, Agent, or Firm-Johnston, Keil, Thompson 21 Appl. No. 203,453 & Shurtleff (30) Foreign Application Priority Data (57) ABSTRACT Nov. 30, 1970 Germany............................ 2058776 Manufacture of vinyl sulfonates and vinylsulfonic acid by saponifying carbyl sulfate under alkaline condi (52) U.S. Cl.............................................. 260/513 R tions. (51) Int. Cl. .......................................... C07c 143/16 3 Claims, No Drawings 3,872,165 1 2 MANUFACTURE OF VINYL SULFONATES AND nates is obtained in a substantially pure form without WNYLSULFONCACID FROM CARBYL SULFATE the formation of a plurality of by-products. This object is achieved in a process for the manufac This invention relates to a process for the manufac ture of vinyl sulfonates and vinylsulfonic acid by treat ture of vinyl sulfonates and vinylsulfonic acid by the sa ing carby sulfate under alkaline conditions optionally ponification of carbyl sulfate under alkaline conditions. followed by liberation of vinysulfonic acid by treatment lt is known to prepare vinyl sulfonates from 6-halo of the resulting vinyl sulfonates with acids, in which ethane sulfonates by treatment with alkalis or by alka process the vinyl sulfonates are prepared in two stages, line hydrolysis of G-chloroethanesulfonic chloride; the in the first of which there is added to an aqueous basic ammonium salt of vinylsulfonic acid can also be pre 10 solution or suspension an amount of carbyl sulfate pared by the hydrolysis of 1,2-ethanedisulfonic chlo which is equivalent to the hydroxyl ion portion of the ride. Another possible route is via the hydrolysis of the solution, said addition being at such a rate that the pH dichloride of ethanedisulfonic acid-1,2 with water or of the mixture during the addition remains between 9 alcohol or with sodium acetate in glacial acetic acid. and 12 and the temperature remains between 30 and The vinyl sulfonates produced by these processes are 5 50°C, and in the second stage the reaction solution is obtainable, however, only in a strongly discolored form heated to from 70 to 150°C. and are very impure due to side reactions. Thus it is The starting material for the process of the invention necessary to effect expensive and time-consuming re is carbyl sulfate prepared in known manner from ethyl crystallizations, which are associated with considerable ene or ethanol and sulfur trioxide. It is advantageous to losses of material, if it is desired to obtain polymeriz 20 purify the carbyl sulfate so that it contains no more free able compounds. The salts manufactured in this man sulfur trioxide. ner have only a limited number of commercial applica The basic solutions are conveniently based on an al tions due to the fact that the starting materials are not kali or alkaline earth metal hydroxide solution or sus readily available and because of the high price of the pension. The process of the invention is preferably car products. Furthermore, a drawback common to all of 25 ried out using an alkali metal hydroxide solution, in the previously proposed methods of manufacture is particular a sodium hydroxide solution, or an alkaline that considerable quantities of common salt and other earth metal hydroxide solution or suspension, in partic salts are produced in alkaline hydrolysis and the quanti ular a calcium hydroxide solution or suspension. tative separation of such salts is very troublesome and The basic solutions are conveniently used as 3M to very expensive. Moreover, the remaining traces of ani 30 10M aqueous solutions. The alkali metal hydroxides ons, particularly chloride ions, are detrimental to poly are preferably used in the form of 5M to 9M solutions merization in many cases or are responsible for corro and the alkaline earth metal hydroxides in the form of sion of the apparatus. 3M to 4M solutions. It is known from Regnault, Ann., Band 25, p. 32 35 During addition, the pH must be between 9 and 12. (1838) and Magnus, Ann., Band 31, p. 249 (1839) that When the carbyl sulfate is added to an alkali metal so carbyl sulfate may be prepared from ethylene or abso lution the pH is preferably between 9 and li, and when it is added to an alkaline earth metal solution the pH is lute alcohol and sulfur trioxide and that carbyl sulfate preferably between 10 and 11. Temperatures are kept may be saponified with water to form isethionic acid or between 30 and 50°C during the period of addition. In can be converted to vinyl sulfonates by alkaline saponi 40 the case of alkali metal hydroxides the temperature is fication. The alkaline hydrolysis of carbyl sulfate to vi preferably between 35° and 40°C, whilst it is preferably nylsulfonates as described in the above citation is, in kept between 30° and 35°C when alkaline earth metal deed, possible in principle under laboratory conditions hydroxides are used. with the gradual addition of very small amounts of car The subsequent heating to 70°-150°C is necessary to byl sulfate. However, under large-scale conditions the 45 ensure complete conversion to vinyl sulfonate. When use of this method involves insurmountable difficulties the reaction proceeds in the presence of alkaline earth due to the large amount of heat of reaction of more metal salts, subsequent heating is preferably carried out than 400 kcal/kg. Even if the carbyl sulfate is treated at from 100 to 150°C, whilst in the case of alkali metal in a strongly alkaline medium, for example caustic hydroxides heating to preferably 70-80°C is sufficient. soda, summation of the heats of reaction causes this to 50 Precipitation of the vinylsulfonates is conveniently be heated at the interface to such an extent that the effected by cooling the reaction solution to from 0 to main product is isethionate together with a little vinyl 3°C in the case of alkali metal vinyl sulfonates, and it sulfonate, this being due to the base-catalyzed addition is sufficient to cool to only 70°-90°C in the case of alka of water at the double bond. Once its sultone ring has line earth metal vinyl sulfonates, as these are much less been opened, carbyl sulfate is not resistant to aqueous 55 soluble. alkali when the temperature is above 40°C. If, to coun The process of the invention may be carried out in a teract this, the reaction is carried out at room tempera number of ways. ture or even lower temperatures, the reaction rate falls Where caustic soda is used, the reaction may be car to such an extent that the reaction assumes a "frozen" ried out, for example, in a circular tube system, i.e., a condition which is interrupted by occasional explosive 60 cooled closed loop. The basic solution is circulated, bursts of reaction, polysulfonates and isethionate being generally in the form of a 20-28% aqueous caustic soda formed. It is well known that the formation of these un solution, to which a predetermined amount of carbyl desirable by-products increases in an acid medium, so sulfate is added until a pH of 10 is reached. pH meas that it has not hitherto been possible to operate under 65 urements are generally carried out with a pH electrode. acid conditions. Further 20-28% caustic soda solution is continuously It is an object of the invention to provide a method added to the circulated mixture, during which opera of preparing vinyl sulfonates in which the vinyl sulfo tion the pH must not exceed the above value and the 3,872,165 3 4 temperature must be maintained at, for example, from if necessary. The total consumption of 25% NaOH so 32 to 35C. The overflowing liquid is collected in a lution is 368 parts/hr. After a residence time of 30 min tank which is heated to, say, 70°C and maintained at a utes, the reaction solution is cooled by a scraper crys pH of 11, to which end further 20-28% caustic soda so tallizer to from 0 to -3°C while the pH is reduced to lution is added if necessary. 9 by the addition of dilute sulfuric acid. The sodium After a residence time of from 10 to 60 minutes and vinyl sulfonate solution is then separated from the pre preferably of about 30 minutes the reaction solution is cipitated sodium sulfate by centrifuging and the residue cooled to from 0 to 3°C while the pH is simultaneously is elutriated with a little cold water. reduced to an average value of 9 with an acid, for ex There are obtained 292 parts/hr of vinyl sulfonate so ample sulfuric acid. Separation of the sodium vinyl sul O lution having the following characteristics: fonate solution from the sodium sulfate formed as a by solids content: 33.5% product is conveniently carried out in, say, a centri iodine number (hydrogenation): 56.7 (= 29% of so fuge. - dium vinylsulfonate) When calcium hydroxide is used as the reaction me Na2SO content: 1.5% dium for the saponification of carby sulfate, it is con 15 venient to charge the carbyl sulfate in solid form to a sodium isethionate content: 3.0% stirred vessel, in which the equivalent amount of cal color number (Klett): 21 cium hydroxide in water has already been placed.