Propylene conditions using

Figure 11-16. Freezing points of aqueous solutions of ethylene and propylene glycol. (Used by permission 1977ASHRAEHandbook, l-P Ed., Fundamentals, 1979 ASHRAE Handbook and Product Directory, 1979,1980 2"= printing, American Society of Heating, Refrigerating, and Air-Conditioning Engineers, Inc. All rights reserved.)...

Table II summarizes the yields obtained from the CONGAS computer output variable study of the gas phase polymerization of propylene. The reactor is assumed to be a perfect backmix type. The base case for this comparison corresponds to the most active BASF TiC 3 operated at almost the same conditions used by Wisseroth, 80 C and 400 psig. Agitation speed is assumed to have no effect on yield provided there is sufficient mixing. The variable study is divided into two parts for discussion catalyst parameters and reactor conditions. The catalyst is characterized by kg , X, and d7. Percent solubles is not considered because there is presently so little kinetic data to describe this. The reactor conditions chosen for study are those that have some significant effect on the kinetics temperature, pressure, and gas composition.

Some of the results obtained by Ben-Taarit et al. for propylene oxidation on Cu2+Y are similar to those reported by Mochida et al. when an excess of propylene is used in the feed [2]. The former authors stress that under these circumstances Cu+2 in Cu +Y is transformed to a Cu°/Cu20/Cu0 mixture. However, using optimized 02/propylene ratios, flow rates and temperatures, it seems that 70% selectivity for acrolein at 50% propylene conversion is achievable. Under those conditions there was no evidence for the formation of either a metallic or an oxide copper phase [2]. 

Approximately 90% of the used alkylation acid was converted to dipropyl sulfate and approximately 90% of the dipropyl sulfate formed was sent back to alkylation wherein the sulfuric acid was reaenerated or recovered. Overall, approximately 80% of the used alkylation acid was recovered. The reactions of sulfuric acid with propylene is an equilibrium reaction, and by the method of operation described it is not possible to convert all of the acid to extractable dialkyl sulfates some will remain as alkyl acid sulfate. In addition, with the extraction conditions used it is not possible to extract all of the dialkyl sulfates formed. 

Katzer (28) observed that counterdiffusion of benzene and cumene within the pores of H-mordenite does not occur at low temperatures. However, H-mordenite shows activity for the alkylation of benzene with propylene to form cumene under the liquid phase conditions used for the diffusion studies, and he has suggested that reaction must occur on the external crystallite surface, or just within the pore mouth. In earlier studies on the isomerization of 2,3-dimethylbutene-l at 0°-20°C over a deuterated Y-type faujasite (62), we observed that the extent of isomerization (2,3-dimethylbutene-2) was far greater than the extent of deutera-tion only a fraction of the total deuterium on catalyst OD groups was exchanged. One possible explanation—assuming a protonic isomerization mechanism—is that, because of lowered intracrystalline diffusion rates... 

Similar to polyethylene, the presence of a large number of peaks with relatively equal intensity in the pyrogram suggests that the pyrolysis mechanism starts with a random scission. The presence of alkanes, alkenes, and dienes shows that this process is terminated by disproportionation. The peak with relatively higher intensity is the propylene trimer (2,4-dimethyl-1-heptene), probably the most stable compound in the pyrolysis conditions used for this particular experiment. 

Under the differential reaction conditions used in this study [12], the concentrations of all products in the gas phase are small and therefore their respective surface coverages are small. Under these constraints, the following kinetic expressions apply for the partial oxidation of propane to propylene, and propylene to acrolein, respectively ... 

There is one exception in these results using propane relative to those obtained when propylene was used to represent the hydrocarbon in extremely lean conditions, the HC activity was enhanced by the presence of SO2 this effect has been reported in previous laboratory studies of propane oxidation [26], We suggested previously that SO2 promotes acid catalysis of propane dehydrogenation, only in this case, the carbonaceous material may be more easily removed from Pt-Rh than from Pd under oxidizing conditions, thus complete oxidation of propane dominates over coking. Other factors, however, may also be... 

Propylene, catalyst, cocatalyst, donor, hydrogen, and comonomer (for random copolymers) are fed into the loop reactor propylene is used as the polymerization medium (bulk polymerization). The loop reactor is designed for supercritical conditions and operates at 80-100°C and 50-60 bar. The propylene/polymer mixture exits the loop reactor and is sent to a fluidized-bed, gas-phase reactor, where propylene is consumed in polymerization. This reactor operates at 80-100°C and 25-35 bar. Fresh propylene, hydrogen and comonomer (in case of random copolymers) are fed into the reactor. After removing hydrocarbon residuals, the polymer powder is transferred to extrusion. 

Phenol and its O-alkyl derivatives (from propylene dimers, trimers, or tetra-mers) are oxyalkylated usually at atmospheric pressure or under moderate pressure conditions using basic catalysts at approximately 50°-200°C in the absence of solvents. Glass reaction flasks are the typical labware, thus the... 

Oxetane compounds also polymerize with the aid of aluminum trialkyl-water acetylacetone catalysts. The reactions can take place at 65 °C in heptane and yield very high molecular weight polymers. These polymerizations, however, are ten times slower that similar ones carried out with propylene oxide, using the same catalyst. The reaction conditions and the high molecular weights of the products led to assumptions that coordinated mechanisms of polymerizations take place. ... 

Table 10.2 summarizes a systematic study of propylene polymerization using rac-Me2Si(2-Me-4-Ph-Ind)2ZrCl2/MAO in the presence of p-MS/hydrogen. The in situ chain transfer reaction is evidenced by its comparison with control reactions carried out under similar reaction conditions without hydrogen and/or p-MS. A small amount of p-MS used alone (control 2) effectively stops the polymerization of propylene. The introduction of hydrogen (runs 1 ) restores the catalyst activity run 4 exhibits about 85% of the catalyst activity of control 1 (a polymerization without any CTAs). 

These results suggest that, under the experimental conditions used, propylene molecules concentrated mainly in the mesopore area, where the subsequent coke deposition resulted in the progressive closure of mesopores and the decrease in BET surface area. The higher the temperature and the reaction time, the higher the amount of coke deposited in the mesopores and the higher the decrease in... 

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