Methylcarbonic acid

Conventional synthetic chemistry needs a multi-step synthesis to give the cyclo-hexadiene diol in the tram-form, which is difficult to polymerize 251). A most ingenious feature of the work of Ballard et al. was the use of a bacterial fermentation route to prepare the diol in the m-form. A detailed account of the preparation, properties and transformation of the polymer has recently been published 252). In practice, the favoured esters are those of methylcarbonic acid, since the eliminated acid decomposes at transformation temperatures to yield methanol and C02. The main... 

The stoichiometry is 2.0 for the two former reactions and 3.0 for the latter, in which the initially formed methylcarbonic acid decomposes instantaneously. Of these three reactions the first is the best documented. The reaction data and the cr+ values obtained are given in Table 9.11. 

It then appears analogous to benzenesulfonic acid (as methylcarbonic acid). The remarkable preparation of propionic acid by action of carbon dioxide on cthylsodium, which has very recently been discovered by WanMyn, can then be understood in the same way as the formation of benzenesulfonic acid from benzene and sulfuric acid anhydride. 

The DMC derivative is another preferred one for aromatization for practical reasons, as the eliminated acid is methylcarbonic acid, which decomposes to methanol and carbon dioxide. This DHCD-DMC aromatization process is catalyzed by alkali metal salts and a tertiary organic nitrogen compound. Tertiary bases such as n-octylamine, the oligo bases, and other bases of low volatility are the preferred catalysts for the process at 240°C using 0.5 mol%. Moreover, the base can be removed by volatilization at 350°C after the conversion is complete. This is definitely an advantage over using metal salts (Ballard et al. 1994). 

Thermolytic Cleavage of Allvlic and Benzvlic Ethers and Polvethers. The thermal lability of the types of ethers which are of interest in the context of this study was discovered during a thorough study of the application of certain benzylic carbonates as labile protecting groups for alcohols and phenols [IS]. It was observed that, under acid catalysis, the bis-methylcarbonate derivative of l-(4-hydroxyphenyl)ethanol (4, in Equation 1) was transformed into the benzylic ether (5) which then underwent clean acid-catalyzed thermolysis to the corresponding styrene (6) in very high yield [14]. 

SYNS 4 -CARBOMETHOXY-2,3 -DIMETHYLAZOBENZOL CARBONIC ACID METHYL-4-(o-TOLYLAZO)-o-TOLYL ESTER 2,3 -DIMETHYLAZOBENZENE-4 -METHYLCARBONATE... 

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