Browsing by Author "Cundall, Robert B."

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    Selective Free Radical Reactions with Proteins and Enzymes: The Inactivation of Subtilisin Carlsberg and Subtilisin Novo
    (Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1974, 70 (12), 1974) Bisby, Roger H.; Cundall, Robert B.
    Reactions of the selective inorganic radical anions (SCN)–2 and Br–2, with subtilisins Novo and Carlsberg lead to selective oxidation of the tryptophan, tyrosine, and histidine amino-acid residues. Inactivation studies show that most of the inactivation is caused by oxidation of one or more histidine residues. Oxidation of tryptophan residues has a minor effect upon activity but damage to tyrosine residues does not affect the activity of the two enzymes towards the small synthetic substrate N-acetyl-L-tyrosine ethyl ester. Rate constants for reactions with the radical anions and transient spectra, measured by pulse radiolysis, reflect the differences in amino-acid composition and in structure between the two enzymes.
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    Shock tube studies of the high temperature pyrolysis of acetylene and ethylene
    (Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1978, 74 (06), 1978) Cundall, Robert B.; Fussey, David E.; Harrison, Andrew J.; Lampard, Desmond
    Shock heating of acetylene and ethylene, under the conditions 1500–2500 K, 1–2 bar and molar fraction 0.07–2 % hydrocarbon in argon, has produced spectrographic evidence concerning the products of pyrolysis. Kinetic spectrophotometry was used in the wavelength range 250 nm-1.5 µm. The variation of the absorption spectra with temperature, hydrocarbon pressure and time were investigated, and suggest that polyacetylenes were formed. Simple kinetic analysis has given rate constants for the formation of polyacetylenes and the polyacetylene concentration was found to reach an equilibrium value within the observation time in some cases.
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    Vapour pressure measurements on some organic high explosives
    (Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1978, 74 (06), 1978) Cundall, Robert B.; Palmer, T. Frank; Wood, Colin E. C.
    Equilibrium vapour pressures of 1,3,5-trinitrobenzene (TNB), 2,4,6-trinitrotoluene (TNT), 2,4,6-trinitro-m-xylene (TNX), 2,4,6-trinitromesitylene (TNM), 2,4,6-trinitroaniline (TNA), 2,4,6-trinitro-m-phenylene diamine (DATB), 2,4,6-N-tetranitro-N-methylaniline (Tetryl), 2,4,6-trinitrophenol (picric acid), 2,4,6-trinitroresorcinol (styphnic acid, TNR), 2,4,6-trinitro-m-cresol (TNC), pentaerythritoltetranitrate (PETN), cyclotrimethylenetrinitramine (RDX), sym-cyclotetramethylene-tetramitramine (HMX) and nitroguanidine have been measured over a range of temperature using the Knudsen cell technique. The data were found, within the limits of experimental error, to follow the Clausius–Clapeyron equation and values for the constants A and B in the integrated form of the equation log10p/N m– 2=A–B/T determined. The standard enthalpies, entropies and Gibbs energies for sublimation are quoted.