Hydrolysis of ether linkages

To evaluate the role that water may play during kerogen decomposition, the following hydrolysis reactions have been studied  

R stands for any hydrocarbon functional groups. The reason we include is to 

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The problem with solvents is that in most cases they decompose under the reaction conditions used in the reductive carbonylation reaction. Solvent decomposition can occur in a variety of ways including (i) acid cleavage of ether linkages by HI and HCo(CO), (ii) well known hydrolysis and halogenation reactions. 

Benzaldehydes (lg, 2g, 3g) are liberated in the same way but originate in part from other sources (cf. Fig. 6.1.2). The presence of benzoic acids (lh, 2h, 3h) and ferulic acid (1 j) can be explained by hydrolysis of ether or ester linkages. p-Flydroxybenzoic and p-coumaric acids (3h and 3j, respectively) are attached to certain types of lignins by ester linkages and their occurrence in the acidolysis mixtures is, in these cases, at least primarily due to the hydrolysis of these linkages. 

Pyrolysis in the presence of tetramethylammonium hydroxide (TMAH) at a lower temperature of 300° C was studied for both PES and PSF [11]. In this study, the main component for the thermally assisted hydrolysis and methylation of PES was dimethyl derivative of bis(4-hydroxyphenyl)sulfone. This compound was formed through selective cleavages of ether linkages maintaining intact the sulfone structures. For PSF thermally assisted hydrolysis and methylation at 300° C, the main constituents were dimethyl derivative of bis(4-hydroxyphenyl)isopropylidene (bisphenol A) and also dimethyl derivative of bis(4-hydroxyphenyl)sulfone. A partial decomposition of the sulfone groups in PSF during the THM reaction also was noted. The findings also were confirmed by matrix assisted laser desorption mass spectrometric measurements. 

Hydrolysis is a reaction of water with another substance to yield one or more reaction products. In context with RR, mainly ester and ether groups are being hydrolyzed. Because h. of esters in - oleo-chemistry and h. of glucosidic bonds in saccharide chemistry are different as to starting materials, reaction conditions and end products, they are covered under the following keywords - hydrolysis in oleochemistry, - hydrolysis of glucosidic linkages. 

This analysis is normally performed by HPLC (see Chapter 7) or, after hydrolysis of the sulfate group, by GC. Wet chemical methodology may also be applied if the sulfate groups are hydrolyzed, the determination of unethoxylated material can be performed in the same way as for alcohol ethoxylates. Hydrolysis conditions must be mild to avoid rupture of ether linkages. 

Another method for the hydroxylation of the etliylenic linkage consists in treatment of the alkene with osmium tetroxide in an inert solvent (ether or dioxan) at room temperature for several days an osmic ester is formed which either precipitates from the reaction mixture or may be isolated by evaporation of the solvent. Hydrolysis of the osmic ester in a reducing medium (in the presence of alkaline formaldehyde or of aqueous-alcoholic sodium sulphite) gives the 1 2-glycol and osmium. The glycol has the cis structure it is probably derived from the cyclic osmic ester ... 

Alcohol and alcohol ether sulfates are commonly considered as extremely rapid in primary biodegradation. The ester linkage in the molecule of these substances, prone to chemical hydrolysis in acid media, was considered the main reason for the rapid degradation. The hydrolysis of linear primary alcohol sulfates by bacterial enzymes is very easy and has been demonstrated in vitro. Since the direct consequence of this hydrolysis is the loss of surfactant properties, the primary biodegradation, determined by the methylene blue active substance analysis (MBAS), appears to be very rapid. However, the biodegradation of alcohol sulfates cannot be explained by this theory alone as it was proven by Hammerton in 1955 that other alcohol sulfates were highly resistant [386,387]. 

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