Condensation and polymerization products

Polyacetylenes (or Polyynesj. See under Acetylenic Condensation and Polymerization Products in Vol 1, A62-L to A63-L. Selected polyacetylene expl compds as an adjunct to this article are presented below, as well as addnl refs Addnl Refs 1) A.L. Henne K.W. Greenlee, Preparation and Physical Constants of Acetyl-... 

Acetylene Condensation and Polymerization Products may be obtained by subjecting acetylene to the action of heat, light electrons, alpha-rays, elec discharge, etc with or without catalysts (Ref 1, i892-3ll One such products is cuprene(qv), which is a condensation product of acetylene and not a polymer as it is usually called. The real polymerization product of acetylene is... 

Naphtenic hydrocarbons yield products similar to paraffins upon oxidation. Aromatic hydrocarbons are che most readily oxidized constituents of lubricating oils. The end products are very complex condensation and polymerization products and tend to be Insoluble in oil. These products constitute the sludges, resins and varnishes which allegedly cause piston ring sticking in the engine. 

Methane and carbon monoxide, according to Losanitsch and Jovitschitsch,4 unite to acetaldehyde and its condensation and polymerization products according to Hemptinne,5 aldehydic substances. 

Polyamides, commonly known as nylons, may safely be used to produce articles intended for application in processing, handling, and packaging of food, including for products intended to be cooked directly in their packages. Nylon resins are manufactured by condensation of hexyamethylenediamine and adipic acid (nylon 66) or sebacic acid (nylon 610), by the polymerization process, e.g., of co-laurolactam (nylon 12), or by condensation and polymerization, e.g., nylon 66 salts and s-caprolactam. 

Petroleum or crude oil is a naturally occurring complex mixture, composed mainly of hydrocarbons. Although there are, without any doubt, numerous compounds that have been formed directly from biologically produced molecules, the majority of petroleum components are of secondary origin, either decomposition products or products of condensation and polymerization reactions. 

Straight acetylene can be used as an explosive when in liquefied or solidified form (see Acetylene as an Explosive) (See also Acetylene Condensation or Polymerization Products, Acetylene Derivatives, Acetylene Hydroperoxides Peroxides, Acetylene-Nitric Acid Reactions, Acetylene Reactions, Acetylenic Compounds, Acetylides, Cuprene and Halogenated Acetylenes)... 

Mos of the solid carbonaceous material available to industry is derived from the pyrolysis of petroleum residues, coal, and coal tar residues. Understanding the reactions occurring during pyrolysis would be beneficial in conducting materials research on the manufacture of carbonaceous products. The pyrolysis of aromatic hydrocarbons has been reported to involve condensation and polymerization reactions that produce complex carbonaceous materials (I). Interest in the mechanism of pyrolysis of aromatic compounds is evidenced in a recent study by Edstrom and Lewis (2) on the differential thermal analysis of 84 model aromatic hydrocarbons. The study demonstrated that carbon formation was related to the molecular size of the compound and to energetic factors that could be estimated from ionization potentials. 

The usual temperature of flue gas entering the shield section is 1300-1650°F and should be 200-300°F above the process temperature at this point. The proportions of heat transferred in the radiant and convection zones can be regulated by recirculation of hot flue gases into the radiant zone, as sketched on Figure 8.19(b). Such an operation is desirable in the thermal cracking of hydrocarbons, for instance, to maintain a proper temperature profile a negative gradient may cause condensation of polymeric products that make coke on the tubes. Multiple chambers as in... 

In 1947 Szwarc prepared a white polymeric material u by rapid flow pyrolysis of p-xylene under reduced pressure. On the basis of p-xylylene diiodide 2) detected in the reaction mixture of the pyrolysis products with iodine gas he proposed a formation 1,3) of p-xylylene(p-quinodimethane) (QM) in this pyrolysis. He claimed the polymeric material to be poly-p-xylylene(poly-QM)and proposed a mechanism 2) for the formation of poly-QM, involving thermal cleavage of carbon-hydrogen bonds of p-xylene to yield p-xylyl radicals which collide with each other to give p-xylene and QM through disproportionation. QM condenses and polymerizes to produce poly-QM. 

Copolymerization of Chloro- and Dichloro-/>-xylylene. Trichloro-di-p-xylylene (XVIII) was obtained by chlorination of di-p-xylylene with three molar equivalents of chlorine. Pyrolysis yielded monomers XV and XIX, which were condensed and polymerized on a 90 °C. surface. A quantitative yield of product was obtained. The product was transparent, tough, self-extinguishing, had a softening point above 280°C., and exhibited the correct elemental analysis for copolymer XX. Owing to the low solubility of the chlorinated poly-p-xylylenes, no attempts... 

These data as presented in the patent are evidently conventionalized and the products designated probably represent characteristic fractions obtained in the distillation of the dry product. Substances not reported but which in all probability are present in the product include methanol, formaldehyde, formic acid, esters, amyl alcohols, and possibly heavier compounds formed by condensation and polymerization. 

References may be found in the literature to attempts made for the purpose of reacting ethylene in a variety of other ways to obtain useful products. Condensation and oxidation products are claimed to lie formed when ethylene mixed with steam, ammonia, or hydrogen sulfide is passed over catalysts at high temperatures.811 Unsuccessful attempts have been made to obtain acetone by reacting ethylene with hydrogen and carbon monoxide in a molal ratio of 1 2.5 1, respectively, at 300° C. and 150 to 250 atmospheres pressure in the presence of a basic zinc chromate catalyst. In this case methanol was formed, a portion of the ethylene polymerized, and a portion was reduced to ethane.888 No acetone was formed. 

The further oxidation of benzaldehyde to benzoic acid is complicated also by the numerous condensations and polymerizations that occur. At 350° C. benzaldehyde decomposes to benzyl benzoate with the formation of some benzene and carbon monoxide.128 At the same temperature benzyl benzoate decomposes to benzoic anhydride, toluene, and benzalde-hyde. At temperatures of 700° C. carbon monoxide and benzene are the chief decomposition products of benzaldehyde and some diphenyl and triphenyl also form. In the presence of catalysts aud oxygen further reactions lead to the formation of complicated gums and tars which involve losses, make separation of the product difficult and effectively destroy the activity of the catalyst by coating it over. 

Catalysts. The non-catalytic oxidation of naphthalene either in the liquid phase under pressure or in the vapor phase at atmospheric pressure, results in the formation of complete combustion products if temperatures high enough to give good reaction rates are used or else results in die formation of complex tars by condensations and polymerizations of intermediates if such low temperatures are used as to necessitate the use of long times of contact to obtain appreciable reaction. Hence, to obtain valuable products from the oxidation in commercial yields it is essential that catalysts be used. 

A study of the bulk properties of seawater humic substances was carried out by Kerr and Quinn (1975), while a detailed structural analysis was undertaken by Stuermer (1975) and Stuermer jmd Harvey (1978). Stuermer discussed the structural features in terms of origin, chemical and physical properties, interaction in the sea and eventual fate. As an example of the formation of a humic substance in seawater, we will discuss Stuermer s proposed structure of seawater fulvic material (Gagosian and Stuermer, 1977), the precursor compounds to its formation, and the condensation and polymerization reactions responsible for its synthesis. Although the material isolated by Stuermer represents only a small portion of the total hiunic material, it serves as an example of a possible condensation product. 

The methylol compounds produced by these reactions are relatively stable under neutral or alkaline conditions, but undergo condensation, forming polymeric products under acidic conditions. Consequently, the first step in making an amino plastic is usually carried out under alkaline conditions. The amino compound and formaldehyde are combined and form a stable resin intermediate that may be used as an adhesive or combined with filler to make a molding compound. The second step is the addition of an acidic substance to catalyze the curing reaction, often with the application of heat to cure the amino resin to the solid cross-linked state. In this reaction, the methylol group is probably protonated and a molecule... 

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