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The alcoholysis of acetyl chloride, propionyl chloride and butyryl chloride with some alcohols in acetone and toluene has been investigated by means of calorimetric measurements. Furthermore a comparison with benzoyl chloride has been made. In the case of i-propanol in acetone, a smaller rate constant has been found for the alcoholysis of propionyl chloride than for butyryl chloride. In contrast to this, almost equal rate constants have been determined for the reactions of these acyl chlorides with n-propanol and ethanol. In toluene, the rate constants for the reaction of acetyl chloride with all considered alcohols has the highest values under similar conditions but then decrease from acetyl chloride to butyryl chloride. The observed differences and the changes of rate constants are discussed and compared with literature data.

The alcoholysis of acetyl chloride under various reaction conditions has been investigated by isoperibolic calorimetry and HPLC-analysis. Non-linear kinetic evaluation has been realized by the program TA-kin 3.3 on the basis of temperature and concentration data. Depending on the excess of alcohol, different partial reaction orders are found. The reaction rate also depends on the basicity of the solvent. This could be caused by H-bonding with the alcohol increasing the activation energy. It was possible to distinguish between the kinetic parameters of the ethanolysis and the i -propanolysis of acetyl chloride in the evaluation of the alcoholysis of acetyl chloride by alcoholic mixtures at stoichiometric concentrations of the reagents. A partial order of n =0.5 for the alcohol, as determined in the evaluation of the single alcoholysis under these conditions, has been confirmed. The results show that heat accumulations are an important feature for the kinetic evaluation of reactions under the concentration conditions described.

The ethanolysis of acetyl chloride has been compared to the methanolysis and the hydrolysis, as well as to the reaction with n -propanol, n -butanol and n -pentanol in acetone and in toluene, to reveal chain-length effects. Pentanol, heptanol and nonanol have been included as well in the investigation, but at lower concentrations. Structural influences on the alcoholysis of acetyl chloride have been studied with the isomeric C 3 and C 4 -alcohols in acetone and in toluene. Furthermore, alcoholysis of acetyl chloride with some C 7 -alcohols and the reaction of benzoyl chloride with different types of alcohols have been investigated.

Part A of this series of papers (Parts B to E follow) presents the data and methods used, as well as the results obtained by participants in the ICTAC Kinetics Project. The isothermal and non-isothermal data sets provided were based on a hypothetical simulated process as well as on some actual experimental results for the thermal decompositions of ammonium perchlorate and calcium carbonate. The participants applied a variety of computational methods. Isoconversional and multi-heating rate methods were particularly successful in correctly describing the multi-step kinetics used in the simulated data. Reasonably consistent kinetic results were obtained for isothermal and non-isothermal data. There is, of course, no ‘true’ answer for the kinetic parameters of the real data, so the findings of the participants are compared. An attempt has been made to forecast the tendencies for the future development of solid state kinetics.

In 1994 the decomposition of calciumoxalate monohydrate as a three-step reaction has been investigated by 13 labs using the TG-method. The authors working group performed objective kinetic evaluations of 144 TG data sets obtained from the same charge of substance in different laboratories. A non-linear optimization procedure was applied for different reaction models to perform single and overall optimizations. The results were analyzed critically on the basis of real model concepts for the course of the dehydration, the CO-split off and of the CO2-split off, respectively. The results allow an optimistic assessment for the application of kinetic procedures to solid state reactions with well-known chemical course investigated by TG.

Investigations in chemical safety are necessary in case that the reaction course depends on changes of the reaction conditions sensitively. To break off a conversion in a hazardous situation, the precision calorimeter ACTRON 5 is equipped with two safety pumps. They empty and rinse the reactor with cold solvent. The pumps will be activated automatically. For testing the calorimeter the complex reaction of chloronitrobenzene with alkalined alcohol was used and break off at predefined conditions. The possibility of the kinetic estimation of these break-off files is shown.

Polyethers, which are produced by alcoholysis of oxiranes, are often used as solvents in chemical plants. The spectra of the products can be influenced by the choice of the catalyst (acid or base). The results of the base-catalyzed ethanolysis of 1,2-epoxybutane are displayed. The reaction was investigated calorimetrically by varying the molar ratio between ethanol and 1,2-epoxybutane, the starting temperature and the concentration of the catalyst sodium hydroxide. Additionally, the influence of the used alcohol will be shown in one example. To determine the activation parameters, the experiments were evaluated by the nonlinear software package TA-kin v3.3.

Differential scanning calorimetry is well suited to record heat productions of chemical and physical processes as data for the following kinetic analysis. To obtain kinetic parameters of complex reactions, nonlinear optimization methods have to be used. Such complex reaction systems are polymerizations. We tried to evaluate measurements of the epoxy cure and the polymerization of s-propiolactame with simple and complex models. In both cases the simple models did not produce satisfactory results. But by using complex models a successful fitting of the measured data was possible. Our investigation shows that the combination of DSC and modern nonlinear evaluation methods presents a suitable tool for the kinetic investigation of polymerizations.

Acetylation of different hexanediols as a complex reaction has been investigated by calorimetry. The calorimetric curves demonstrate that the reaction rate depends on the molecular structure. In case of 1,6- and 2,5-hexanediols, the activation parameters have been obtained by nonlinear evaluation procedures with the program TA-kin v3.3. The kinetic results show, that the formation of the diester is characterized by higher activation energies than that of the monoester.

The kinetic control of exothermic reactions plays an important role in chemical safety technology. Predictions of thermal explosions by runaway, e.g. redox reactions, poly reactions, and decompositions, are required in case of simple as well as of complex reactions. Activation parameters of chemical reactions are often stressed by systematic errors which are caused by failures in accuracy of measurement and calibration. The influence of systematic errors for some selected reactions has been investigated by the software package TA-kin. The coupling between continuous data evaluation software and the precision calorimeter ACTRON 5.0, including a safety scenario equipment, was established to test the validity of calculated runaway predictions under practical conditions. Measured data are applied for kinetic evaluations by nonlinear optimization methods in real time. In this way, the experimental investigations of reaction systems become possible beyond the point of no return without any danger for the laboratory.

In view of earlier results obtained with rodents, the present study was designed to investigate the effect of acute zinc deprivation in man on plasma zinc concentration and the response ofplatelets to aggregating agents. Three adult men consumed a formula diet based largely on soybean protein for 12 to 14 days. During the control period the diet was supplemented with 12 mg zinc per day. Without supplementation the diet supplied approximately 0.5 mg zinc per 3.0 Mcal; it contained 0.7 ppm zinc, and 0.2% phytate. After removal of the zinc supplement plasma zinc dropped rapidly and reached a minimum by the 5th day. There was a wide diurnal variation in plasma zinc concentration in one subject with the overnight fasting value being the highest and decreasing soon after the morning meal. Platelet aggregation in response to ADP and arachidonate was impaired when plasma zinc was 60 �sg/dl or less and was restored to normal within 19 h of oral zinc supplementation. These results demonstrate that plasma zinc can be rapidly decreased by dietary zinc deprivation and that extracellular zinc plays an important role in platelet aggrega- tion. Am J Clin Nutr l982;35:ll3-l19.