A kinetic model dC/dt=α+βC1/2 for suspension polymerization of vinyl chloride was developed. Kinetic studies on such polymerization were carried out in a stainless steel tube reactor in the presence of high-, medium-, or low-activity initiators at different concentrations, and at temperatures ranging from 50 to 62℃. Twenty-six sets of kinetic data were obtained under different conditions. According to these experimental results, the acceleration behavior of vinyl chloride polymerization was discussed in detail. It is proposed that the auto-acceleration effect is due to the decrease of the termination rate constant in the polymer-rich phase and to the increase of initiator concentration owing to volume contraction during polymerization with an initiator of lower activity. All plots of dC/dt against C are nonlinear during the two-phase stage, while dC/dt versus C1/2 curves show much better linearity up to 80-70% conversion. The proposed model can he used to explain satisfactorily why the reaction order of initiators is between 0.5 and 1.0.

The dehydrogenation of tetralin over Ni-Mo/Al2O3, Fe2O3/Al2O3, Fe2O3 and FeS2 has been shown in this investigation to be a typical consecutive reversible reaction, with a small amount of 1, 2-dihydronaphthalene as an intermediate. On the less-active catalyst Fe2O3, a trace of 1, 4-dihydronaphthalene (DHN) is also formed-the more active the catalyst, the lower the concentration of DHN. The rate of dehydrogenation rises with an increase of the partial pressure of tetralin, and declines with an increase of the partial pressure of hydrogen. It was observed that DHN is much more active than tetralin and naphthalene, and in the presence of a catalyst, it can be converted rapidly into naphthalene and tetralin. The fact that hydrogen can accelerate the hydrogenation of DHN is thought to be the main reason for its inhibiting action on the dehydrogenation of tetralin. In the presence of a catalyst, 1,4-DHN is unstable and can be isomerized into 1,2-DHN very quickly. The different catalysts studied have almost the same order of activity for dehydrogenation of tetralin, conversion of DHN and hydrogenation of naphthalene. On the hypothesis that the reaction is a consecutive one on the catalyst surface and that the adsorbed DHN is a very active intermediate, a reaction model was deduced. The equilibrium constants of adsorption and the rate constants of the catalytic reaction were calculated. The curves so calculated fit very well the experimental data, thus showing the validity of this model. Certain experimental results were explained in the light of this model and the related parameters.

Equations for the steady state were derived with regard to the multistage cascade enrichment of isotopes. For any column the procedure for calculating the flow rate was simplified by using the concept of the degree of equilibrium for the column terminal. A set of Type 1-5 glass cascade was set up on the basis of these equations. By using the CO2/di-n-butyl-amine (DNBA)/triethylamine (TEA) system and feeding the cascade with commerical cylinder-grade CO2, 13C was enriched from natural abundance to 96.25 atom%, after a period of a little over 5 months operation. The cooler-condensers above the digestor, absorber and exchange column of each stage were cancelled in succession after accumulation of experi-mence from cascade operation. The structure of the cascade was thus simplified and its construction cost considerably decreased. An automation also became feasible, enabling the steady operation of the cascade for a long time.

By using Friedel-Crafts catalyst a family of soluble and fusible polymers has been synthesized by polycondensation of an aralkyl ether, such as p-di (methoxy)-xylene or 4,4/-di(methoxymethyl) diphenyl ether with any of ten kinds of aromatics such as phenol, cresol, or phenyl ether. Their average molecular weight is about 2000 and their chemical and physical structures have been determined. When cross-linked, these polymers have a good thermal stability. Their pyrolysis temperatures are over 400℃ with activation energies around 100 kJ/mol.

The kinetics of liquid-phase oxidation of cumene with air using cn-mene hydroperoxide as an initiator has been studied in the temperature range of 100° to 130° C for semi-batch operation. According to the chain free-radical mechanism for liquidphase oxidation of hydrocarbons and the assumed mode for the decomposition of cumene hydroperoxide, a kinetic model for the steady chain-propagation period is derived. On the basis of the experimental results obtained, the rate constants and the apparent activation energy for liquid-phase oxidation of cumene and for the side reaction of decomposition of hydroperoxide are determined. The concentrations of cumene and its hydroperoxide calculated from the kinetic model fit in satisfactorily with the experimental results. In this paper the induction period for the semi-batch operation and the effects of reaction temperature on the conversion of cumene and on the selectivity to cumene hydroperoxide are also discussed.

The thermal and electric behavior of the "K-V" and "K-Na-V" catalyst series for SO2 oxidation has been studied in the working state by means of gas-flow differential thermal analysis (DTA), thermogravimetric analysis (TGA)and electric conductivity analysis (ECA). Changes in catalyst composition and characterization of catalyst distribution for different kinds of samples have been studied by means of X-ray diffraction(XRD) and scanning electron microscopy (SEM). From changes in catalyst behavior, as observed in different experiments, the reaction mechanism designated as "double temperature range, double vanadium complex and two step" is presented. The simplest model of the mechanism is

On the basis of the Soave and Martin-Hou equations, a new cubic equation of state is suggested. Expressions for calculating its constants and the corresponding formulas for its thermodynamic functions were derived. Good agreement was obtained between literature values and results calculated from phase equilibrium constants and dew points for ten binary pairs.

Concentration polarization is an important control parameter for reverse osmosis and ultrafiltration. For rational equipment design and precise predict of the concentration polarization ratio under turbulent flow, an equation for calculating this ratio was obtained by analyzing the results of our previous work. Compared to other data, this equation was found applicable to a wider range of water permeability Fw, especially to high values of Fw for membrane processes.

For size-dependent growth rate of crystals, a simplified model: is derived, where G is the linear growth rate of crystals, L and L0 are characteristic lengths of crystals and nuclei respectively, G∞, and β are model parameters, G∞, being the linear growth rate of extremely large crystals, and β characteristic length of crystals for which linear growth rate equals G∞/2. Equations for crystal size distribution (CSD), suspension density MT and dominant crystal size LD are given. Compared with previous models, most of which are empirical, this model shows a comparable or better fit to the published CDS data for ammonium alum and potash alum. The calculated values of MT agree well with experimental results.

The mechanism and kinetics of hydroformylation of propene under low pressure have been studied, pseudo-first-order equations were derived, and rate constants, activation engery and optimum contact time for producing butyl aldehyde have been calculated. Next, the influence of reactor diameter on absorption efficiency, mass transfer coefficient, axial mixing of liquid and average bubble diameter were examined. The result shows an obvious effect of bubble diameter on propene conversion. Hence bubble diameter should be used as a significant factor for reactor scale-up. A mathematical model based on experiments of hydroformylation of propene in a packed bubble reactor is as follows: where the coefficient of contact efficiency M can be obtained from a three-region model.

Equilibrium t-x-y data were determined under a constant pressure of 500 mm Hg for the binary system of 2,3-dichloropropene ( 1 ) and epichlo-rohydrin (2).The data were correlated with the NRTL equation (I) and UNIQUAC equation (**). For (I), △gI2=4.2487, △g21 = 90.095, (α=0.30); for (**), △u12=321.08, △u21=240.83. Equilibrium vapor pressures were also determined for pure ( 1 ) and ( 2 ) in the temperature range of the present work, and correlated with the Antoine equation.