Tungsten methyl alcohol

Whereas the Mobil process starts with syn gas based methyl alcohol, Olah s studies were an extension of the previously discussed electrophilic functionalization of methane and does not involve any zeolite-type catalysts. It was found that bifunctional acidic-basic catalysts such as tungsten oxide on alumina or related supported transition metal oxides or oxyfluorides such as alumina or related supported transition metal oxides or oxyfluorides such as tantalum or zirconium oxyfluoride are capable of condensing methyl chloride, methyl alcohol (dimethyl ether), methyl mercaptan (dimethyl sulfide), primarily to ethylene (and propylene) (equation 65) . 

Although little experimental data is available, numerous patents have been issued for the vapor phase catalytic oxidation of various other derivatives containing the benzene nucleus, as well as heterocyclic compounds Thus, fluorene (diphenyl methane) is oxidized to fluorenone with air in the presence of a catalyst containing iron vanadate or other suitable metal salt of the fifth or sixth group of the periodic system at a temperature of 360° to 400°.1,2 Maleic acid and anhydride are formed by the catalytic oxidation of compounds of the furan series, such as furan, furfural alcohol, furfural, methyl furfural, hydroxymethylfurfural, pyromucic acid or mixtures, with air over catalysts of molybdenum, vanadium, or other metals.133 Dimethyl benzaldehyde is formed by oxidizing pseudocumene with air at 550° C. in the presence of a tungsten oxide catalyst. Molybdenum, vanadium, or tantalum oxide catalysts may also be used to form aromatic aldehydes from o-, m-, or p-xylenes, mesitylene, p-cymene, or o-chlorotoluene by air oxidation. Times of contact of 0.3 to 0.4 seconds... 

Kupchan et al. achieved the first total synthesis of aristolochic acid involving photocyclization of substituted 2-iodostilbenes [410], Piperonal (689) provided a suitable skeleton to build ring A of aristolochic acid. It was reduced to the piperonoyl alcohol (690) with lithium aluminium hydride. Bromination of 690 afforded 6-bromopiperonoyl bromide (691). It was then hydrogenated to the corresponding 2-bromo-4,5-methylenedioxytoluene by w-butyllithium carbonation method. The toluic acid (693) was converted to acid chloride by oxalyl chloride, and bromination of acid chloride and by radiation with a 200-W tungsten lamp followed by methanolysis afforded the ester 694, which on treatment with silver nitrate produced methyl ester (695). 

High conversions of cyclopentene were obtained by Nuetzel et al. [59] with hydroperoxides, inorganic peroxides, or aromatic nitroderivatives. To increase the stability of some tungsten-based catalytic systems, Witte et al. [63] employed a-halogenated alcohols such as chloroethanol, 2-chlorocyclohexanol, bro-moethanol, l,3-dichloro-2-isopropanol, o-chlorophe-nol, and 2-iodocyclohexanol. It was observed that methyl and ethyl acetals of formaldehyde, acetaldehyde, chloroform, and benzaldehyde impart good staiblity to the binary systems of tungsten, whereas epoxides such as ethylene oxide and butylene oxide lead at the same time to an increase in activity and stability. 

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