Ethylene-carbon monoxide temperature effects

Effect of other factors on cellulose. Dry distillation at a temperature above 150°C causes cellulose to produce compounds of low molecular weight, such as water, methane, ethylene, carbon monoxide, carbon dioxide, acetic acid, and acetone. According to Pictet [49] dry distillation under reduced pressure yields a substance having the empirical formula C6H10Oj, laevo-glucosan which probably is /3-D-glucopyranose anhydride ... 

This is the case, for example, in the copolymerization of carbon monoxide and ethylene where the CO will not add to itself but does copolymerize with the olefin monomer. General theoretical treatments have been developed for such cases, taking into account temperature and penultimate effects. Again, the superiority of these more complicated theories over the simpler copolymer model is not proved for all systems to which they have been applied. 

Studies on the pyrolysis of starch have attracted attention since 1913. In a historically first report, Bantlin determined the following yields of products from rice starch decomposed at temperatures raised within 7 h from 100 to 500° 12% of coke, 30% of water, 3% of tar, 5% of acetic acid, 6% of various aldehydes, 1.1% of ketones, 13% of carbon dioxide, 8% of carbon monoxide, and some hydrogen and ethylene. Sandomini was the first to study the influence of metal oxides (of Al, Cr, and Zn). He did not observe any appreciable effects of these additives on the decomposition at 270 to 300 of several organic compounds, among them starch and cellulose. 

R/R Activation. Figure 5 shows that the enhanced dehydroxyl-ation by carbon monoxide also had a pronounced effect on the termination rate during polymerization. In these experiments, two series of Cr/silica catalyst samples were activated and allowed to polymerize ethylene to a yield of about 5000g PE/g. In one series the catalyst samples were simply calcined five hours in air as usual at the temperatures shown. The relative melt index potential (RMIP) has been plotted against activation temperature and the expected increase up to the point of sintering was observed. 

The experiments were carried out in small stainless steel autoclaves having an internal volume of 700 mL. The autoclaves, having been charged with a particular catalyst solution and gas mixture of interest, were mounted vertically in electrically heated ovens. The factors affecting the rate of the reaction are partial pressure of carbon monoxide, partial pressure of ethylene, catalyst concentration, temperature, base concentration/pH, and the nature of the base. Carbon monoxide has an inhibitory effect upon the reaction. The rate of reaction increases linearly with ethylene pressure in the low-pressure regime but exhibits saturation at ethylene pressures exceeding 17 atm. The reaction is second order with respect to catalyst concentration. The nature of the base used deter-... 

It has been reported that use of a suitable co-solvent increases the concentration of the olefin in water (catalyst) while retaining the biphasic nature of the system. It has been shown that using co-solvents like ethanol, acetonitrile, methanol, ethylene glycol, and acetone, the rate can be enhanced by several times [27, 28], However, in some cases, a lower selectivity is obtained due to interaction of the co-solvent with products (e.g., formation of acetals by the reaction of ethanol and aldehyde). The hydroformylation of 1-octene with dinuclear [Rh2(/t-SR)2(CO)2(TPPTS)2] and HRh(CO)(TPPTS)3 complex catalysts has been investigated by Monteil etal. [27], which showed that ethanol was the best co-solvent. Purwanto and Delmas [28] have reported the kinetics of hydroformylation of 1-octene using [Rh(cod)Cl]2-TPPTS catalyst in the presence of ethanol as a co-solvent in the temperature range 333-353 K. First-order dependence was observed for the effect of the concentration of catalyst and of 1-octene. The effect of partial pressure of hydrogen indicates a fractional order (0.6-0.7) and substrate inhibition was observed with partial pressure of carbon monoxide. A rate eqution was proposed (Eq. 2). 

It is well-known that the occurrence of chain defects, in the form of for example small methylene sidegroups, could reduce this Tm-value [4J. This offered the possibility to reduce the relative high processing temperature of PK copolymers. The effect of addition of small amounts of propylene to the carbon monoxide/ ethylene mixture on the Tm-value is shown in Figure 9.1. A nearly linear decrease of the Tm-value as a function of the weight percentage of C3 was found for propylene concentrations between 0 and about 15 %wt. i.e. for the Tm-value holds ... 

Effect of Temperature. Figure 3 gives data showing the conversion of the carbon in the coal to the hydrocarbon gases methane, acetylene, and ethylene, and to carbon monoxide and carbon dioxide. The conversion data are plotted vs. the measured temperature without regard for variations in the other operating variables. These conversions were computed from the measured volume and composition of the gas produced, after condensation of the water vapor and the feed rate of the coal. 

The apparatus and the general experimental technique employed were the same as those described earlier 8). Experiments were conducted by the static method in the gas phase. The products of the reaction were released from the bomb at the reaction temperature. Commercial ethylene (99.2% pure), carbon monoxide (prepared in the laboratory by the action of formic acid on concentrated sulfuric acid), distilled water, A.E.. grade n-propyl, and n-butyl alcohols were the reactants used. The ethylene gas contained a small amount of sulfur, which, however, was found to have no deleterious effect on the synthesis. 

Of the substances investigated methane was the one which did not affect the activity of the catalyst. In fact, the investigations showed that any adsorbed methane could be purged off the catalyst effectively by hydrogen gas at room temperature, as shown in Table II. This purging method was not completely effective at room temperature for carbon monoxide and ethylene, the other non-permanent poisons tested. 

Absent from Table 10 are the comonomers carbon monoxide, carbon dioxide, and sulfur dioxide. These comonomers are not included because their copol mieiization does not obey the normal copolymer model illustrated by reactions (vix—xvii) and hence cannot be described by kinetic parameters which take into account only these reactions. For example. Furrow (/28) has i own that caibon dioxide will react with growing polyethylene chains in a free-radical reaction, but that it terminates the chains giving carboxylic acids. It does not copolymerize in the usual sense (which would give polyesters). Carbon monoxide and sulfur dioxide appear not to obey the normal cppol3nner curve of feed composition versus polymer composition and it has been reported that these materials form a complex with ethylene whidi is more reactive than free CO or SOg, perhaps a 1 1 complex. Copolymerization of both CO and SO is further complicated by a ceiling temperature effect. Cppolymerization has been carried out with ethylene and these monomers, however, and poly-ketones and pol3Tsufones are the resultant products. 

Copper and copper alloys exhibit special catalytic effects in the electroreduction of carbon dioxide. They represent unique cathode materials, which can electrocatalytically convert CO2 and water into hydrocarbons and alcohols, at ambient temperature and atmospheric pressure [2]. So far, copper metal is the only electrode material able to produce significant amounts of hydrocarbons at high reaction rates and over 50% Faradaic yield, over a sustained period of time. Its drawbacks are that a copper electrode can operate only at high overpotential (of almost 1 V), and a mixture of major and minor products are obtained, which contains hydrogen, ethylene and methane [43,47,88]. In these reactions, carbon monoxide appears to be a key intermediate, and its further reduction yields a series of reaction products [2,89]. Copper cathodes can be operated at high current density in aqueous... 

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