Reaction study procedure

In the course of a long and thorough study of the polymerisation of isobutene (IB) by syncatalytic systems based on aluminium-organic compounds (Magagnini et al., 1977 and preceding papers) measurements were made by a Biddulph-Plesch type reaction calorimeter fitted with conductivity (k) electrodes on polymerisations of IB by Et2AlCl + Cl2 in MeCl at -45 °C, from which a kp+A value could be obtained. The reactions and procedures can be summarised as follows ... 

For qualitative investigations there is considerable latitude in experimental procedure. There are few limitations on solvent for reactions studied in the liquid phase, although standard considerations of susceptibility to radical attack must obviously be taken into account. With polar solvents it may be desirable to replace the normal silica sample tube with a flat cell, although spin-adduct concentrations are usually sufficiently great for this to be circumvented by the use of capillary tubes. 

In another article, however, [59] it was shown that in the most case this reaction gave mixtures of two heterocycles 53 and 54. To develop procedures allowing regioselective synthesis of both heterocyclic systems, the authors of [59] studied an influence of temperature regime and catalyst type on the direction of this MCR. With application of ultrasonication and microwave irradiation it was estabhshed that the reaction studied can pass under kinetic and thermodynamic control. 

The number of bands present in a spectral window and their centers of symmetry are pre-requisites to other signal processing procedures i. e. curve fitting. For in situ spectroscopic reaction studies, a set of tracks can be assigned which specify the centers of symmetry for all the bands. Since the bands move as a function of composition, the tracks in a matrix or AF %xv drift. 

Oxidation Reactions. Description of the reaction conditions, procedures, and details of the analytical techniques used in this study have been reported elsewhere (2y 35) and are summarized here. 

Since the way we carry out calculations evolves, it is necessary to go back and see if the new approaches still give satisfactory results for reactions studied some time ago. Ideally we want to have the current procedures coded into the computer programs written to automate NBT, so that the current procedure can be tested against examples of previously studied reactions to be sure that... 

XRD experiments can be carried out to characterize gas-solid reactions and, with some limitations, fluid-solid reactions more generally, as long as the fluid contributes little to the pathway of sight for the X-rays. Areas of recent investigation are catalytic gas-solid reactions, electrochemical processes, synthesis procedures involving precipitation and dissolution of solids, temperature-programmed reaction studies of crystallization, and oxidation and reduction of solids. This enumeration covers essentially all phases of the life of a catalyst. 

The obvious advantage of our photochemical procedure is that it allows the formation of 3 under mild conditions at very low temperature. Thereby, thermally rather unstable derivatives of 3 may be generated and their reactions studied.- This enabled us, for example, to show that stereochemical configurations at the diene termini are retained during photolysis, but may be lost by subsequent, rather rapid thermally induced intramolecular rearrangement steps. For example, irradiation of 10 in the presence of pure (Z,Z)-2,4-hexadiene at -60°C yields exclusively s-trans-Tj -(Z,Z)-2,4-hexadiene)zirconocene [3h-(Z,Z)]. At -40°C, the stereochemical information at one terminal diene carbon center is lost. A clean... 

The precise experimental conditions used can greatly influence the efficiency, or even the course, of the Ritter reaction. Representative procedures are available, along with a comprehensive tabular survey to 1966, in the article by Krimen and Cota. Optimum reaction times (typically 1-24 h) and temperatures (typically 20-50 °C) depend very much on e particular cases. Typical temperatures of 0-10 °C are used when hydrogen cyanide or hydrogen fluoride are employed. Benzenesulfonic, fluoroboric, formic, hydrofluoric, methanesulfonic, perchloric, phosphoric, polyphosphoric, sulfuric, toluenesulfonic and tri-fluoromethanesulfonic acids are amongst those used to generate the carbenium ion. However, the majority of workers favor sulfuric acid and, in cases where comparative studies have been carried out, - ... 

Reaction Procedures. All reaction studies were performed with reactor-equilibrated catalyst samples. A standard catalyst charge weighed between 100 and 125 milligrams with an average particle diameter of 275 microns. The catalyst bed was centered between two beds of quartz particles with the same average particle diameter as the catalyst. The quartz beds were used to thermally insulates the catalyst and reduce the axial temperature gradient (< 5°C) across the catalyst bed. 

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