Journal of Chemical Technology & Biotechnology

doi: 10.1002/jctb.5010171208pmid: N/A

Smith, D. G.

doi: 10.1002/jctb.5010171201pmid: N/A

The reasons for polymerisation rates not conforming to mathematically predicted relationships are reviewed. Such non‐ideal kinetics may result from one or more of the following causes: invalid basic assumptions, degradative transfer, effect of monomer concentration on rate of initiation, diffusion control of termination, and formation of electron‐donor/acceptor complexes. Details of the characteristics of each effect are given.

Ledwith, A.

doi: 10.1002/jctb.5010171202pmid: N/A

The development of simple, stable, and well defined catalyst systems for the initiation of ionic polymerisation is reviewed. The principles involved are illustrated by reference to the use of potassium t‐butoxide in dimethyl sulphoxide for initiating anionic polymerisation of ethylene oxide and of the hexachloroantimonate salt of the triphenyl methyl cation for polymerisation of tetrahydrofuran. Other stable organic cations initiate polymerisation via charge transfer complexes and can give rise to cation‐radicals as intermediates. It is suggested that related cation‐radicals may play a role in lignin biosynthesis.

Thomas, W. J.

doi: 10.1002/jctb.5010171203pmid: N/A

The precision of laminar jet techniques for the determination of diffusion coefficients in gas‐liquid systems is considered. It is shown that diffusion coefficients for the CO2‐water system can be obtained with a 1–2% accuracy, but that in many cases reported in the literature this precision is not achieved. This is due to abnormalities in the jet at the receiver or to vibration.

Bott, T. R.; Schulz, S.

doi: 10.1002/jctb.5010171204pmid: N/A

The solubilities of chlorine in a solution containing 250 g/litre of sodium chloride, at different pH values (in the range 1–2.5) have been experimentally determined at different chlorine partial pressures and at temperatures of 50° and 75°. The results show some slight divergence from data previously reported in the literature but these were obtained by a different procedure.

Blake, W. E.; Randle, J.

doi: 10.1002/jctb.5010171205pmid: N/A

Very dilute solutions containing zinc sulphate, sodium and sulphuric acid were passed down a column of Zeo‐Karb 225 cation‐exchange resin, and the volume at which zinc first appeared in the effluent (breakthrough volume), together with the volume at which the concentration of zinc in the effluent became equal to its concentration in the influent (equivalent volume), were determined.

Knypl, E. T.; Wojdylo, S. Z.

doi: 10.1002/jctb.5010171206pmid: N/A

Liquid‐liquid equilibrium data at 25° for the system water‐isopropyl alcohol‐ethyl benzene together with refractive index and density data for mixtures on the binodal curve, are presented. A number of correlation methods were found to represent satisfactorily the equilibrium data and comparison is made with known water‐isopropyl alcohol‐benzene and water‐isopropyl alcohol‐toluene systems.

Tsuchiya, Yoshio; Sumi, Kikuo

doi: 10.1002/jctb.5010171207pmid: N/A

When plastics are involved in a fire they may yield toxic decomposition products. Some quantitative data on the decomposition products of plastics are available in the literature, but it is difficult to assess the danger from the different amounts of various products because of the absence of a suitable method of evaluation. The authors have proposed a method of evaluation based on pyrolysis followed by gas chromatographic analysis and have used it to assess toxicity from various thermal decomposition products of polyvinyl chloride. Hydrogen chloride was found to be the main toxic decomposition product.