Sulfur Alkylation

Sweetening of the FCC gasoline is usually sufficient to meet its sulfur specifications. However, in areas where reformulated gasoline is marketed, sulfur specifications in the gasoline may require more treatment. The mercaptans in the LPG need to be extracted to protect the downstream processes, such as alkylation. Sulfur increases acid consumption and produces undesirable by-products. 

These compds are also formed during the prepn of nitriles, by heating aryl or arylalkyl halides, or alkyl sulfuric or phosphoric esters, or arylsulfonic esters with K or Na cyanide in ale... 

A similar complementarity has been observed in LAH vs. DIBAL reduction of / -ketosulfoxides in which the keto group is also part of a conjugated enone system (equation 32)69. After reductive cleavage (Li, EtNH2) of the alkyl-sulfur bond, 3-alken-2-ols of high enantiomeric purity are produced59. 

Pure alkyl sulfuric acids are white crystalline solids with definite melting points but they are hygroscopic. Hygroscopicity increases as the chain length increases. Dodecyl, tetradecyl, hexadecyl, and octadecyl sulfuric acids were obtained by Maurer et al. [57] by chlorosulfation of the corresponding alcohols and the melting points obtained are shown in Table 2. 

Acyclic alkyl phenyl sulfones undergo an alkyl-sulfur bond cleavage [123] however, in cyclic arylsulfones the aryl-sulfur... 

Alkyl sulfates are conjugate bases of the very strongly acidic alkyl sulfuric acids and are very good leaving groups. Dimethyl sulfate is less expensive than CH,I, the only liquid methyl halide at room temperature. Liquids are easier to use than gases in laboratory syntheses. 

Although a large number of thieno[2,3-af]pyrimidines have been synthesized from pyrimidine precursors, most have evolved from pyrimidines bearing a carbonyl moiety at C-5 and an alkylated sulfur at C-6. Either 6-thiol- or 6-chloropyrimidines may be used. In the latter case, displacement of the chlorine by a sulfur anion is commonly used. In general, pyrimidines of the type (264) are the immediate precursors or are formed in situ. For most of the investigations the derivatives (264 R = R3 = Me R2 = aryl) have been used. The cyclization to the products (265) can be effected by... 

Chemetics has developed a process for treating spent alkylation sulfuric acid with nitric acid to produce a sulfuric acid that can be used to acidulate phosphate rock, the major use for sulfuric acid. The organic contaminants are converted to carbon particles that are removed with the gypsum on filtration of the phosphoric acid. Special alloys are used in the fabrication of the acid reactor. Topsoe developed and, by the year 2005 had built, more than 45 Wet Sulfuric Acid (WSA) process units. This process is especially suited for... 

Fluid Coking and Cracking, Delayed Coking, Alkylation, Sulfur Plants, and Sour Water Strippers... 

Alkyllithium reagents also yielded the corresponding alkylated sulfur-stabilized allenyl anions. Thus, treatment of 286 with -BuLi gave the lithio derivative 287 which was reacted with the aldehyde 288. Upon acidification with trifluoroacetic acid (TEA), the furan-containing diester 289 was obtained in 67% yield (Scheme 36) <2002CC2824>. 

Alkylation (sulfuric acid effluent Stratco/DuPont bpd 4,000 20,000 0.160 0.6... 

Originally it was believed that etherification with sulfuric acid proceeded through the intermediate formation of alkyl sulfuric acids (R0S03H), since these products sometimes could be isolated from the reaction mixture. It now seems clear, however, that alkyl sulfuric acids are formed only as by-products in the reaction and are not actually intermediates in the etherification process. Thus, ethyl ter -butyl ether was prepared in yields of 95 per cent by heating a mixture of tert-butyl and ethyl alcohols containing 15 per cent sulfuric acid at 70°, yet titration of the cooled reaction mixture showed no evidence of the formation of an alkyl sulfuric acid.4 Furthermore, the yield of diethyl ether was 95 per cent when ethanol was passed through concentrated sulfuric acid heated to 140°, but when the reaction was carried out with ethyl sulfuric acid at the same temperature, much sulfur dioxide was evolved and the yield dropped to 70 per cent.4 8 We can, therefore, conclude that the... 

Sung, S. Szechy, G. Albright, L.F. Decomposition of spent alkylation sulfuric acid to produce... 

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