Pentaerythritol, catalytic oxidation

The largest and oldest chemical intermediate use for methanol is formaldehyde. Over half of the methanol currently consumed in the world goes into formaldehyde production. Formaldehyde is produced by the catalytic oxidation or the oxidative dehydrogenation of methanol The major outlet for formaldehyde is amino and phenolic resins. These resins are in turn used in the manufacture of adhesives for wood products, molding compounds, binders for thermal insulation and foundry resins. Formaldehyde is also consumed in the production of acetal resins, pentaerythritol, neopentyl glycol, trimethylolpropane, methylenediphenyldiisocyanate (MDI), and textile treating resins. 

Ethyl alcohol has been made by the hydration of ethylene (9) since 1930. Like isopropyl alcohol, part of the output is used as a solvent, but most is converted to other oxygenated chemicals. Its most important raw material use is conversion to acetaldehyde by catalytic air oxidation. Acetaldehyde, in turn, is the raw material source of acetic acid, acetic anhydride, pentaerythritol, synthetic n-butyl alcohol (via aldol condensation), butyraldehyde, and other products. Butyraldehyde is the source of butyric acid, polyvinyl butyral resin, and 2-ethylhexanol (octyl alcohol). The last-named eight-carbon alcohol is based on the aldol condensation of butyraldehyde and is used to make the important plasticizer di-2-ethylhexyl phthalate. A few examples of the important reactions of acetaldehyde are as follows ... 

Amorphous Sn-, Si-, and Al-containing mixed oxides with homogeneous elemental distribution, elemental domains, and well-characterized pore architecture, including micropores and mesopores, can be prepared under controlled conditions by use of two different sol-gel processes. Sn-Si mixed oxides with low Sn content are very active and selective mild acid catalysts which are useful for esterification and etherification reactions [121]. These materials have large surface areas, and their catalytic activity and selectivity are excellent. In the esterification reaction of pentaerythritol and stearic acid catalytic activity can be correlated with surface area and decreasing tin content. The trend of decreasing tin content points to the potential importance of isolated Sn centers as active sites. 

Pentaerythritol (13), which contains four identical primary hydroxyl groups, is oxidized catalytically in the presence of one mole of alkali per mole at 35° to tris(hydroxymethyl)acetic acid (14). The reaction stops at this stage, since the three remaining hydroxyl groups are more difficult to oxidize ais soon as a carboxyl group has been introduced into the molecule. Attempts to oxidize the molecule further, by using more severe conditions, resulted in degradation. 

A pentaerythritol-based dendrimer modified with bis-terpyridyl Ru(II) was shown to be effective as a catalyst for the electrochemical oxidation of methionine (L-Met) and cystine (L-Cys) in aqueous solution or the mixed solvent AN-water (12% AN) [100]. In this case, the dendrimer was mixed with carhon powder and, using a sol-gel hinder, the carhon electrode doped with the [Ru(tpy)2] " -functionalized dendrimer was prepared. The oxidation peak of [Ru(tpy)2] was enhanced by the addition of L-Met, indicating the electro-catalytic effect of the dendrimer. Using the composite electrode doped with the dendrimer as an amperometric detector for flow-injection analysis, a linear calibration curve was obtained over the range 1-lOpM of L-Met in phosphate buffer (pH 7.0). A similar cahbration curve was obtained for L-Cys over the range 1-10 pM in phosphate buffer (pH 2.3). 

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