Aliphatic depolymerization product

Therefore, CL and die depolymerized product from which CL is regenerated contain various impurities which are present in widely fluctuating amounts depending on the reclamation processes involved. In particular, the presence of cyclohexanone, cyclohexanone oxime, octahydrophenazine, aniline, and other easily oxidized compounds affects die permanganate number. Also volatile substances such as aniline, cyclohexylamine, cyclohexanol, cyclohexanone, nitrocy-clohexanone, and aliphatic amines may also be present in the CL.22... 

Suberized Cell Walls. An analogous set of CPMAS experiments is presented for suberin in Figure 6. Because this polymer is an integral part of the plant cell wall, the 13C NMR spectrum had contributions from both polysaccharide and polyester components. Chemical-shift assignments, summarized in Table IV, demonstrated the feasibility of identifying major polyester and sugar moieties despite serious spectral overlap. Semiquantitative estimates for the various carbon types indicated that, as compared with cutin, the suberin polyester had dramatically fewer aliphatic and more aromatic residues. A similar observation was made previously for the soluble depolymerization products of these plant polymers (1,8,11). 

The following comments are made with regard to a correlation of the depolymerization product yields with the relative reactivities of aliphatic-aromatic carbon and oxygen-carbon bridge structures in coal ... 

Little has been published on the use of the suberin depolymerization products as monomers for the synthesis of novel macromolecular materials, which has so far concentrated on polyurethanes and polyesters using the mixture of aliphatic monomers. 

Transesterification performed at 170-200°C in the presence of aliphatic carboxylic acids, such as adipic acid, after the depolymerization of PET in EG and propylene glycol leads to unsaturated polyesters. These materials are used in foam production or for the production of polyurethanes and polyester polyol copolymers [7-9]. 

This picture has been broadly validated, and in some respects refined, by other work in which coal was depolymerized by acid-catalyzed transalkylation [as by interaction of coal with phenol and BF3 (23-27)] or by similar, less clearly defined, phenolation reactions (28-31), or selectively degraded by specific oxidants, such as dichromates (32-34), hypohalites (35-38), or peroxy-acids (39-43). But these studies have also revealed some previously unsuspected features. Buffer-controlled oxidation with Na2Cr207 (34) and KMn04 (44) have indicated an occasionally significant presence of straight-chain (up to C21) and branched-chain (up to C8) aliphatic compounds in coal. Oxidation with performic acid (41-43) has yielded substituted compounds that are clearly related to the microbial or chemical degradation products of lignin or flavonoids. And when applied to supposedly very similar coals, virtually identical depolymerization or oxidation procedures often furnished distinctly different product slates (45). 

The first information concerning the synthesis of cyclic carbonates was revealed by Carothers et al in the early 1930s. " Cyclic carbonates were obtained by the depolymerization of respective linear oligocarbonates at high temperature in the presence of various catalysts combined with distillation under reduced pressure. The products (yields of40-80%) consisted of a mixture of volatile cycles (mostly monomeric and dimeric cyclic carbonates).The most effective catalysts in this process were Sn(II), Mn(II), Fe(II), and Mg(II) chlorides, carbonates, and oxides. This method is still applied in the synthesis of six- and seven-membered and of larger size aliphatic cyclic carbonates. 

It is at times desired that vinyl articles biodegrade—or at least vanish into a landfill. Reports to date suggest that vinyl articles are immortal in landfills. Even with use of aliphatic plasticizers, degradation is limited to cracking and fracture. There are no reports of catalysts for depolymerization under landfill conditions comparable to the effects of cobalt and manganese catalysts used with landfillable polyolefin products such as trash bags. In the case of vinyl, such catalytic action would be unacceptable if accompanied by formation of vinyl chloride monomer or evolution of HCl. 

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