Hydrogen chloride catalyst

Currently, almost all cumene is produced commercially by two processes ( /) a fixed-bed, kieselguhr-supported phosphoric acid catalyst system developed by UOP and (2) a homogeneous AlCl and hydrogen chloride catalyst system developed by Monsanto. 

AlCl and Hydrogen Chloride Catalyst. Historically, AIQ processes have been used more extensively for the production of ethylbenzene than for the production of cumene. In 1976, Monsanto developed an improved cumene process that uses an AIQ. catalyst, and by the mid-1980s, the technology had been successfully commercialized. The overall yields of cumene for this process can be as high as 99 wt % based on benzene and 98 wt % based on propylene (60). 

Thioketals are readily prepared by reaction of saturated 3-ketones with thiols or dithiols in the presence of boron trifluoride or hydrogen chloride catalysts. Selective protection of the 3-ketone in the presence of a 6-ketone is possible by carrying out the reaction in diluted medium. Similarly, 3-ketones react selectively with monothiols " " or with bulky dithiols in the presence of 6-, 7-, 11- and 12-ketones. 

In the sol-gel procedure for the preparation of hybrids, polymeric acid catalysts such as poly (styrene sulfonic acid) were also used instead of hydrogen chloride [14]. The polymeric acid catalyst was effective for the preparation of hybrids at a similar level to that of hydrogen chloride catalyst. In some cases, the increased modulus was observed due to the higher extent of reaction. No difference was observed in morphologies between the hybrids prepared with polymeric and small molecule acid catalysts. The method using polymeric acid catalyst may depress the ion-conductive property, characteristic to the mobile acidic small molecules. Polymeric catalyst may also influence the rheology of the resulting hybrids. 

The mechanism described above does not explain the fact that imder controlled conditions, benzene in the presence of aluminum chloride-hydrogen chloride catalyst, inhibits not only the cracking but also the isomerization reaction (Table XXV, experiment 3) while in the absence of benzene cracking is the predominant reaction. The mechanism postulated above does not take into consideration the observations made that under controlled conditions saturated hydrocarbons such as methylcyclopentane, cyclohexane, or butanes (7, 23, 35) do not undergo isomerization, unless traces of olefins are present. 

The trialdehyde 38 was obtained in four steps in 60-65% overall yield from trimesic acid (34, Scheme 3). Esterification of 34 with 1-propanol in excess, by refluxing with hydrogen chloride catalyst, leads to triester 35 in quantitative yield. Hydrogenation of 35 in acetic acid solvent (Pt catalyst) yields pure cij,ds-cyclohexane-l,3,5-tricarboxylate ester 36, also in quantitative yield. Reduction of ester 36 with lithium aluminum hydri in tetrahydrofuran solvent produces c ,cis-l,3,5-tris(hydroxymethyl)cyclo-hexane cis,cis-37) in 90-95% yields. Swern oxidation of triol 37 led to cij,c -l,3,5-triformylcyclohexane 38 in 70% yield. The stereochemistry of 38, as well as that of precursors 36 and 37, was established as ca,cis in each case by high resolution H NMR. 

Hydrogen chloride Catalyst, machine cleaner, reduction of chlorinated organics... 

Although the reaction theoretically requires the molar ratio of reactants to be 2 1, an improved yield of bisphenol A is obtained if additional phenol is present the optimum molar ratio is 4 1. In a typical process, the phenol and acetone are mixed and warmed to 50 C. Hydrogen chloride (catalyst) is passed into the mixture for about 8 hours, during which period the temperature is kept below 70 C to suppress the formation of isomeric products. Bisphenol A precipitates and is filtered off and washed with toluene to remove unreacted phenol (which is recovered). The product is then recrystallized from aqueous ethanol. Since epoxy resins are of low molecular weight and because colour is not normally particularly important, the purity of bisphenol A used in resin production is not critical. Material with a p,p -isomer content of 95-98% is usually satisfactory the principal impurities in such material are o,p - and o,o -isomers. 

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