Alkylation of isobutane with C4 olefins. 1. First-step reactions using sulfuric acid catalyst

Absorption Processes of n-Butenes in Sulfuric Acid. 1. Determination of Di-sec-butyl Sulfate, Di-sec-Butyl Ether, and sec-Butyl Alcohol by High-Resolution Gas Chromatography

“…The DBS standard was obtained through distillation of the raw sulfate at 65 "C/0.35 mmHg, resulting in acolorless liquid, characterized by its FTIR spectrum (Figure 1) as compared to Albright et al (1988), Pardini (1991, and band assignment following Detoni and Hadii (1957). 'H-NMR ( Figure 2) and HRGC-MS (Figure 3) completed the identification.…”

“…Also, dimethyl sulfate (1) (RO),SO, + H,O .s ROH + ROS0,H R = alkyl radicals (DMS) hydrolysis by atmospheric moisture has been observed, upon its collection from the atmospheric air by solid sorbenta (Lee et al, 1980). DBS determination by an indirect titrimetric procedure was reported by Albright et al (1988).…”

“…Indirect hydration of n-butenes to sec-butyl alcohol (Lacy, 1931;Engs and Moravec, 1932;Katsuno, 1941;Robey, 1941;Nippon, 1969;Jorn, 1971;Schmidt, 1981) and alkylation of isoparaffins with these olefins (Goldsby, 1971;Albright et al, 1977;Albright et al, 1988) are examples of such processes. The formation of DBS is favored at low temperatures (-20-0 "C) (Albright et al, 1977) and with an excess of olefin (Engs and Moravec, 1932;Katsuno, 1941;Albright et al, 1988;Pardini, 1991). Over the 1980s the world-wide consumption of n-butenes to produce secbutyl alcohol by the indirect hydration process was around 600 thousand metric tons per year.…”

“…Therefore, their quantitation would allow investigation on optimization of these processes as well as gathering of DBS toxicological data. Albright et al (1977) tried to characterize, by gas chromatographic analysis (GC), the residual n-butene content in the organic phase after absorption in concentrated sulfuric acid at -20 "C, but DBS (also contained in the organic phase) decomposed to n-butenes during the GC run (Albright et al, 1988). The samples were not previously treated.…”

Understanding interfacial behaviors of isobutane alkylation with C4 olefin catalyzed by sulfuric acid or ionic liquids

“…Currently, for the isobutane alkylation process the concentrated sulfuric acid (H 2 SO 4 ) still acts as one of the major commercial catalysts, although it suffers from certain drawbacks . Moreover, in the past half centuries both chemical and physical phenomena have been extensively investigated for the isobutane alkylation with H 2 SO 4 as catalyst . According to the previously published works, it is well accepted that the alkylation, which consists of the acid and the hydrocarbon phases, proceeds at or close to the interface of acid/hydrocarbon .…”