Aliphatic glycol oxidation production

Treatment of these samples with SF4 gas to convert the carboxylic acids produced in the weathering process into carbonyl fluorides showed [2, 11] that the acids are actually a mixture of aliphatic and aromatic acids (Figure 18.12). Aromatic acid species are by far the predominant ones, however. The origin of these acids will be discussed below in conjunction with the overall mechanisms of photodegradation. Aliphatic acid species were detected by GC/MS in the artificial device exposure of PECT [11], Note that the PECT copolymer produced more aromatic acids with the same exposure as PET but that the aliphatic acid production was several times higher for the PECT copolymer. The photo-oxidation of the co-glycol must be the reason for this difference. 

We note also that the schemes discussed until now only show the oxidation of the ethylene glycol moiety. In the PECT copolymer, the 1,4-cyclohexylenedi-methylene moiety is also available for oxidation. Indeed, given that the oxidizable hydrogens are tertiary, one reasonably expects a greater ease of production of a radical from that center. Grossetete et al. [11] reported such to be the case with the observation that photo-oxidation reactions occurred much faster with the PECT copolymer than with PET itself. The aliphatic acids that they reported, as identified by the SF4 treatment, could also account for previous aliphatic acid reports [25], This is also additional support that the photo-oxidation mechanism is operating as proposed (Scheme 18.4). 

Direct electrochemical oxidation is not a convenient way for a preparative production of carbonyl compounds from alcohols due to the unselectivity caused by the high oxidation potentials of alcohols. Thus, there have been only a few compounds (some aliphatic alcohols, glycols, and related alcohols) that have been oxidized by the direct method, while the indirect method has often been used to oxidize selectively a variety of alcohols, since it does not... 

Glycols and related alcohols In contrast to aliphatic monoalcohols (1), 1,2-glycols and related compounds (2-methoxy alcohols, 1,2-amino alcohols) can be easily oxidized by the direct electrochemical method [12]. For example, 1,2-cyclopentanediol (9) affords diacetal (10) in 56% yield as the main product (Eq. 3). 

Direct Oxidation. Direct oxidation of petroleum hydrocarbons has been practiced on a small scale since 1926 methanol, formaldehyde, and acetaldehyde are produced. A much larger project (29) began operating in 1945. The main product of the latter operation is acetic acid, used for the manufacture of cellulose acetate rayon. The oxidation process consists of mixing air with a butane-propane mixture and passing the compressed mixture over a catalyst in a tubular reaction furnace. The product mixture includes acetaldehyde, formaldehyde, acetone, propyl and butyl alcohols, methyl ethyl ketone, and propylene oxide and glycols. The acetaldehyde is oxidized to acetic acid in a separate plant. Thus the products of this operation are the same as those (or their derivatives) produced by olefin hydration and other aliphatic syntheses. 

Blends of poly(3-hydroxyalkanoic acid)s (PHAs) with various natural and synthetic polymers have been reported as reviewed in Refs. [21,22]. By blending with synthetic polymers it is expected to control the biodegradability, to improve several properties, and to reduce the production cost of bacterially synthesized PHAs. The polymers investigated as the blending partners of PHAs include poly(ethylene oxide) [92, 93], poly(vinyl acetate) [94], poly(vinylidene fluoride) [95], ethylene propylene rubber [94, 96], po-ly(epichlorohydrin) [97, 98], poly(e-caprolactone) [99], aliphatic copolyesters of adipic acid/ethylene glycole/lactic acid [100] and of e-caprolactone/lactide... 

Graft copolymers were also produced by bubbling alkylene oxides through starch solutions in dimethyl sulfoxide in the presence of potassium naphthenate.2888,2889 Another approach involved grafting polyethylene oxide) to starch. Polyethylene oxide) was converted into a chloroformate derivative and subjected to a reaction with starch alkoxide 2890 Poly(alkylene glycol) could be grafted onto starch by means of cyclic aliphatic acid anhydride in the presence of 4-toluenesulfonic acid 2891 The products were water soluble. 

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