A nonlinear least‐squares method for solving for r1 and r2 the copolymerization reactivity ratios, is explained. This new method is superior to all other methods that have been used heretofore in the following ways: (1) a unique pair of values is obtained which does not depend on the judgment of the person examining the data; (2) this pair of values can be shown mathematically to be the best pair obtainable from the data at hand; (3) the errors are quantitatively defined in meaningful terms: and (4) the data are checked to see how well they fit the copolymer equation. A basis for selecting experimental conditions which will provide data from which precise values of the reactivity ratios can be obtained is explained, and experimental conditions appropriate for obtaining these precise values over a wide range of r1, r2 values are presented in tabular form.
The solubilities of hydrogen and some light hydrocarbons in n-hexane, toluene, and 1,2-dichloroethane at pressures of 1 atm. or less and temperatures of -23°to 25°C. were determined. The data were compared with published values, and discrepancies for hydrogen in 1,2-dichloroethane and for ethylene in toluene in the existing literature resolved. Relevant vapor pressures of the solvents were also measured.The SOLUBILITIES of hydrogen, ethylene, ethane, and propane in binary systems with toluene, as well as the solubilities of hydrogen and ethylene in n-hexane and 1,2-dichloroethane, are reported here. Some of the data are new, whereas others resolve discrepancies in existing literature data. Some new vapor pressure data for 1,2-dichloroethane were also obtained.
EXPERIMENTALApparatus and Procedure for Measuring Solubilities. Two
Propylene, butene‐1, isobutylene, 3,3‐dimethylbutene‐1, and tetradecene‐1 were polymerized at high pressures at 130–150°C. with dixy1tert‐butyl peroxide initiator to give low molecular weight polymers. Free radical copolymerization of propylene and isobutylene was also demonstrated. Facile chain transfer to give relatively stable radicals was blamed for the low rates and degrees of polymerization. The molecular weights were shown to be controlled by chain transfer.
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