Isopropyl hydrogen sulfate

The combination of sulfuric acid addition to propene followed by hydrolysis of the resulting isopropyl hydrogen sulfate is the major method by which over 10 lb of isopropyl alcohol is prepared each year m the United States... 

Indirect Hydration. Indirect hydration is based on a two-step reaction of propylene and sulfuric acid. In the first step, mixed sulfate esters, primarily isopropyl hydrogen sulfate, but also diisopropyl sulfate, form. These are then hydrolyzed, forming the alcohol and sulfuric acid. 

To illustrate the practical application of the method, consider the molecule discussed in the previous section which was identified as either ethyl methyl sulfate or isopropyl hydrogen sulfate. Using the group contributions given in Table 6, one calculates that for ethyl methyl sulfate (C2H50S020CH3) ASH° = — 718.3 kJmol-1, and for isopropyl... 

Propylene is absorbed by concentrated sulfuric acid to form isopropyl hydrogen sulfate. That s subsequently hydrolyzed with water to IPA and dilute sulfuric acid. 

Esterification of propylene with 85% H2SO4 to isopropyl hydrogen sulfate, followed by hydrolysis to the alcohol, is the manufacturing method for isopropyl alcohol. 

Propene undergoes little polymerization when treated with 96% sulfuric acid, the chief product being isopropyl hydrogen sulfate which yields isopropyl alcohol on hydrolysis. When 98% sulfuric acid is used, propylene is converted to conjunct polymer. Ethylene cannot be polymerized by sulfuric acid because the stable ethyl hydrogen sulfate and ethyl sulfate are formed attempts to obtain the polymerization by increasing the reaction temperature are unsuccessful because oxidation occurs. 

Propene Sulfuric acid Isopropyl hydrogen sulfate... 

Recall that alkyl substituents on the double bond increase the reactivity of alkenes toward electrophilic addition. Propene therefore reacts faster than ethylene with sulfuric acid, and the mixture of alkyl hydrogen sulfates is mainly isopropyl hydrogen sulfate, and the alcohol obtained on hydrolysis is isopropyl alcohol. 

The initial step is the absorption of propylene-rich gases into 85% sulfuric acid at temperatures of 20-25°C to form isopropyl hydrogen sulfate via addition of the acid across the double bond (Eq. 19.3). Control of acid temperature and concentration is important to provide selectivity and avoid... 

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