Decomposition propylene

The formation of Ci - C6 hydrocarbons shows that the main reaction is accompanied with side processes of propylene destruction and dimerization with participation of CHx -species and hydrogen is formed at propylene decomposition. The carbon oxide were detected in some experiments due to the dissociation of CO2 => Oads COads on the specific centers of catalyst surface at high temperatures. 

In the present work, propane-propylene mixtures with various ratios were pyrolyzed at temperatures near 900°C and at an atmospheric pressure in an annular flow reactor. Hydrogen was used as a diluent. Under these experimental conditions, it was rather difficult to maintain an uniform temperature throughout the reactor since the reaction rate was high, and consequently, thermal effects due to the heat reaction were significant. In this work, therefore, experimental data at the initial stage of decomposition were analyzed using the effective temperature method to obtain kinetic rate parameters, activation energy and frequency factor, for propane and propylene decompositions. From the relations between... 

Using the experimental results with low conversions and the special experimental technique Jby Towell Martin (11), the order of propane or propylene decomposition was obtained In the copyrolysls system. It was revealed that the rate equations for the component In question were a function of only one concentration variable as follows ... 

Figure 3. Arrhenius plots for propylene decomposition rate in pyrolysis of propane-propylene mixtures...

Figure 4 shows the relationships between the rate constant for propane or propylene decomposition at 900and propane-propylene ratio in the feed. Stubbs et al (9) reported that the... 

Table 3. Arrhenius kinetic parameters of propylene decomposition rates in pyrolysis of propane—propylene mixtures...

Figure 4, Relationships between propane or propylene decomposition rate constant in copyrolysis at Te/f = 900 C and propane-propylene...

Using the experimental results of the pyrolysis of propane-propylene mixtures under the conditions of temperatures near 900 C, atmospheric pressure and hydrogen dilution, the relation between the decomposition rate constant of propane or propylene and the ratio of both reactants was obtained. It was found from the results that propylene had an inhibition effect on propane decomposition, and conversely, propane had an acceleration effect on propylene decomposition. 

To obtain Arrhenius kinetic parameters of propane and propylene decompositions in this system, the experimental results with low conversions were analyzed with the effective temperature method. From the relation between propane-propylene ratio in the feed and... 

The conversion-space time data were used to calculate rate constants and overall reaction orders for propylene decomposition. Reaction order was obtained by plotting the logarithm of rate versus the logarithm of propylene concentration according to the equation ... 

Binary Pt-Ru (50 50) catalyst particles from Alfa Aesar Johnson Matthey have been deposited on different kinds of nanotubes. To ensure the same distribution and amount of catalyst and to pronounce only effect of a support, the deposition of catalyst particles from ethanol suspension was applied for all the nanotubular materials. Entangled NTs prepared by catalytic decomposition of acetylene on a CoxMg(i ()0 solid solution catalyst or stiff nanotubes obtained by propylene decomposition at 800°C using a porous alumina template were studied as a catalyst support. In order to estimate the influence of nanotubes texture on electrocatal3Aic behavior, some samples were further activated by KOH at 850°C during one hour (KOH C= 4 1) or annealed at 2500°C for 1 h. 

The most widely used process for the production of phenol is the cumene process developed and Hcensed in the United States by AHiedSignal (formerly AHied Chemical Corp.). Benzene is alkylated with propylene to produce cumene (isopropylbenzene), which is oxidized by air over a catalyst to produce cumene hydroperoxide (CHP). With acid catalysis, CHP undergoes controUed decomposition to produce phenol and acetone a-methylstyrene and acetophenone are the by-products (12) (see Cumene Phenol). Other commercial processes for making phenol include the Raschig process, using chlorobenzene as the starting material, and the toluene process, via a benzoic acid intermediate. In the United States, 35-40% of the phenol produced is used for phenoHc resins. 

Combination techniques such as microscopy—ftir and pyrolysis—ir have helped solve some particularly difficult separations and complex identifications. Microscopy—ftir has been used to determine the composition of copolymer fibers (22) polyacrylonitrile, methyl acrylate, and a dye-receptive organic sulfonate trimer have been identified in acryHc fiber. Both normal and grazing angle modes can be used to identify components (23). Pyrolysis—ir has been used to study polymer decomposition (24) and to determine the degree of cross-linking of sulfonated divinylbenzene—styrene copolymer (25) and ethylene or propylene levels and ratios in ethylene—propylene copolymers (26). 

Other by-products include acetone, carbonaceous material, and polymers of propylene. Minor contaminants arise from impurities in the feed. Ethylene and butylenes can form traces of ethyl alcohol and 2-butanol. Small amounts of / -propyl alcohol carried through into the refined isopropyl alcohol can originate from cyclopropane [75-19-4] in the propylene feed. Acetone, an oxidation product, also forms from thermal decomposition of the intermediate sulfate esters, eg. 

Ethylbenzene Hydroperoxide Process. Figure 4 shows the process flow sheet for production of propylene oxide and styrene via the use of ethylbenzene hydroperoxide (EBHP). Liquid-phase oxidation of ethylbenzene with air or oxygen occurs at 206—275 kPa (30—40 psia) and 140—150°C, and 2—2.5 h are required for a 10—15% conversion to the hydroperoxide. Recycle of an inert gas, such as nitrogen, is used to control reactor temperature. Impurities ia the ethylbenzene, such as water, are controlled to minimize decomposition of the hydroperoxide product and are sometimes added to enhance product formation. Selectivity to by-products include 8—10% acetophenone, 5—7% 1-phenylethanol, and <1% organic acids. EBHP is concentrated to 30—35% by distillation. The overhead ethylbenzene is recycled back to the oxidation reactor (170—172). 

Salts and Derivatives. Generally the vitamers are high melting crystalline soHds that are very soluble in water and insoluble in most other solvents. Properties of the common forms are Hsted in Table 1. The only commercially important form of vitamin B is pytidoxine hydrochloride (7). This odorless crystalline soHd is composed of colorless platelets melting at 204—206°C (with decomposition). In bulk, it appears white and has a density of - 0.4 kg/L. It is very soluble in water (ca 0.22 kg/L at 20°C), soluble in propylene glycol, slightly soluble in acetone and alcohol (ca 0.014 kg/L), and insoluble in most lipophilic solvents. A 10% water solution shows a pH of 3.2. Both the hydrochloride and corresponding free base sublime without decomposition (16). 

Crocin is a yellow-orange glycoside that is freely soluble in hot water, slightly soluble in absolute alcohol, glycerol, and propylene glycol, and insoluble in vegetable oils. Crocin melts with decomposition at about 186°C and has absorption maxima in methanol at about 464 nm and 434 nm. 

Polyethylene displays good heat resistance in the absence of oxygen in vacuum or in an inert gas atmosphere, up to the temperature of 290°C. Higher temperature brings about the molecular-chain scission followed by a drop in the molecular-weight average. At temperatures in excess of 360°C the formation of volatile decomposition products can be observed. The main components are as follows ethane, propane, -butane, n-pentane, propylene, butenes and pentenes [7]. 

Whereas the electrochemical decomposition of propylene carbonate (PC) on graphite electrodes at potentials between 1 and 0.8 V vs. Li/Li was already reported in 1970 [140], it took about four years to find out that this reaction is accompanied by a partially reversible electrochemical intercalation of solvated lithium ions, Li (solv)y, into the graphite host [64], In general, the intercalation of Li (and other alkali-metal) ions from electrolytes with organic donor solvents into fairly crystalline graphitic carbons quite often yields solvated (ternary) lithiated graphites, Li r(solv)yC 1 (Fig. 8) [7,24,26,65,66,141-146],... 

Sheratte55 reported the decomposition of polyurethane foams by an initial reaction with ammonia or an amine such as diethylene triamine (at 200°C) or ethanolamine (at 120°C) and reacting the resulting product containing a mixture of polyols, ureas, and amines with an alkylene oxide such as ethylene or propylene oxide at temperatures in the range of 120-140°C to convert the amines to polyols. The polyols obtained could be converted to new rigid foams by reaction with the appropriate diisocyanates. 

Fluidized-bed CVD was developed in the late 1950s for a specific application the coating of nuclear-fuel particles for high temperature gas-cooled reactors. PI The particles are uranium-thorium carbide coated with pyrolytic carbon and silicon carbide for the purpose of containing the products of nuclear fission. The carbon is obtained from the decomposition of propane (C3H8) or propylene... 

A question that intrigued several kineticists around 1920 was the following. For bi-molecular reactions of the type A -1- B = Products collision theory gave at least a plausible conceptual picture If the collision between A and B is sufficiently vigorous, the energy barrier separating reactants and products can be crossed. How, though can one explain the case of monomolecular elementary reactions, e.g. an isomerization, such as cyclopropane to propylene, or the decomposition of a mol-... 

A polyether-alcohol, prepared by co-condensation of ethylene oxide and propylene oxide with a polyhydric alcohol, was stored at above 100°C and exposed to air via a vent line. After 10-15 h, violent decomposition occurred, rupturing the vessel. It was subsequently found that exothermic oxidation of the product occurred above 100°C, and that at 300°C a rapid exothermic reaction set in, accompanied by vigorous gas evolution. 

It has been suggested however that isotacticity derives from polymerization occurring on colloidal particles formed by thermal decomposition of the catalysts. As stated previously, in the presence of the monomer even the allyl compounds are stable at 65°C and none of the thermal decomposition products (black to yellow solids) could be detected. As a check on these results a polymerization of propylene was carried out with Zr (benzyl) 4 in toluene at 0°C in a sealed tube. The reaction was very slow and analytical quantities of polymer could be obtained only after 312 hr. NMR analysis showed peaks assignable to isotactic sequences, and these were much stronger than the peaks assignable to syndiotactic diads. It was concluded... 

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