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Polymers
Published in Bryan Ellis, Ray Smith, Polymers, 2008
Processing & Manufacturing Routes: Poly(olefin sulfone)s are obtained by the free-radical reaction ofolefins with sulfur-dioxide. They can also be formed from other dienes and alkynes, though not from acetylene. Another method of preparation is by polysulfide oxidation. Poly(olefin sulfone) is formed from an olefin and sulfur dioxide in the gas phase. Following UV or high energy irradiation, copolymerisation has also been carried out in the solid state with isobutene, butadiene and vinyl acetate at low temp. When the polymerisation is homogenous, the feeds are mixtures of SO2 with the other monomers and perhaps a solvent. Stainless-steel bombs or sealed tubes are used as reaction vessels at elevated temps. where the pressure may rise to > 20 Mpa. For free radical initiation oxygen, ozonides, peroxides, hydroperoxides and hydrogen peroxide-paraldehyde have been used. Initiation is also effected by various forms of ionizing radiation or UV light on monomer feeds. Poly(propylene sulfone) can be moulded between 180 and 200°, and poly(1-butene sulfone) between 125 and 180°. Hot-pressed films have been prepared at 120° from the polysulfones of 1-butene, cyclopentene, and bicyclo-[2.2.1]-2- heptene at high pressures of 140 MN/m2 which prevented decomposition. Synth. has been reported [6,7,8,10,13] some of the polysulfones may be spun into fibres
Health and Safety Information
Published in W. M. Haynes, David R. Lide, Thomas J. Bruno, CRC Handbook of Chemistry and Physics, 2016
W. M. Haynes, David R. Lide, Thomas J. Bruno
Acetaldehyde Acetone Acetonitrile Acrolein Acrylonitrile Allylamine Aniline Anisole Benzaldehyde Benzene Butanal 2,3-Butanedione 1-Butanol 2-Butanone 2-Butanone peroxide trans-2-Butenal tert-Butyl peroxyacetate tert-Butyl peroxybenzoate Carbon disul de Cyclohexanone Diethanolamine Diethylene glycol diethyl ether Diethyl ether Diisopropyl ether Dimethyl sulfate Dimethyl sul de 1,4-Dioxane 1,2-Ethanediamine 1,2-Ethanediol Ethanol Ethylamine Formaldehyde Furfural Furfuryl alcohol Gasolinef Hexylamine Isopropylbenzene hydroperoxide Kerosenef Methanol Methylamine N-Methylaniline Naphthaf Paraldehyde 2,4-Pentanedione 1-Pentanethiol 2-Pentanone 2-Pentanone
A Chemical Model for the Amoco “MC” Oxygenation Process to Produce Terephthalic Acid
Published in Dale W. Blackburn, Catalysis of Organic Reactions, 2020
The Witten process, described above, uses p-xylene to cooxidize the p-toluic acid to produce terephthalic acid. An alternative route is to add a reagent that oxidizes the cobalt(II) to cobalt(III), which keeps the steady-state concentration of cobalt(III) high and pushes the reaction to completion. This in effect, replaces the cobalt(III) lost due to decarboxylation reactions. Acetaldehyde, paraldehyde, and 2-butanone have been used to cooxidize the cobalt.27,28
Thermal desorption behavior of hemiacetal, acetal, ether, and ester oligomers
Published in Aerosol Science and Technology, 2019
Megan S. Claflin, Paul J. Ziemann
The mass spectrum associated with the TPTD peak at 77 °C (Figure 4c) has large peaks at m/z 313 and 157 that also appear in the real-time mass spectrum (Figure 3a), with the former peak corresponding to a mass larger than that of the hemiacetal oligomer (MW 300). These peaks are assigned to an ether oligomer (MW 468) formed through the reaction of three decanal monomers (Figure 2), which results in a structure containing a six-membered ring with three ether linkages (March 1985). Aldehyde trimers are known components of aldehydes obtained from commercial suppliers, and their presence is often noted on product labels. This assignment was confirmed by atomizing a solution of decanal in the absence of 1-nonanol and measuring the real-time mass spectrum shown in Figure S5, which is essentially the same as the one associated with the TPTD peak at 77 °C. The large peaks at m/z 313 and 157 can be explained by fragmentation of the ether oligomer ion according to the pathways shown in Figure S4, the same fragmentation pathways observed for the acetaldehyde trimer, paraldehyde (NIST database [Linstrom and Mallard 2018, https://webbook.nist.gov/chemistry/]). Unlike the hemiacetal oligomer, the ether oligomer mostly stays intact prior to desorption and ionization, although the small peaks at m/z 138, 128, 112, 110, 98, 97, 96, and 95 (Figure 4c) that are characteristic of decanal indicate that a small fraction decomposes reversibly. Since the TIS is proportional to mass (Harrison et al. 1966), we estimate from the fraction of the area under each of the two peaks in the TIS profile that the aerosol consisted of ∼78% hemiacetal oligomers and ∼22% ether oligomers. We note that at the time of these analyses we did not know that aldehyde trimers would be present in the aerosol formed from the synthesized hemiacetal oligomer standard, but its appearance in the sample provided us with a valuable ether oligomer standard for use in this study. Although both the ether and acetal oligomers are bound through ether linkages, the acetal oligomer is formed via a dehydration reaction whereas this ether oligomer is not. As will be discussed below, this distinction can be important in thermal desorption analysis.