Kneading reactions

Both solid-solid and solid-gas types of reactions lead from solid reactants to a solid product without the use of solvents. Solvent-less processes, however, are not necessarily solid-state processes. Indeed, it has been argued [8d,e] that many solid-state syntheses cannot be regarded as bona fide solid-solid reactions because they occur with the intermediary of a liquid phase, such as a eutectic phase or a melt, or may require destruction of the crystals prior to reaction. This latter situation is often observed, for instance, in the case of reactions activated by co-grinding, since the heat generated in the course of the mechanochemical process can induce local melting at the interface between the different crystals, or when kneading, i.e. grinding in the presence of small amounts of solvent, takes place (vide infra). 

Ten grams of aluminum powder and 40g of fine barium peroxide are mixed by shaking with 7g of powdered potassium chlorate. The mixture is kneaded with collodion into balls about one gram in weight, and a 3-inch piece of Mg ribbon is inserted. These spheres are then inserted into a small depression on the top of the reaction mixture. 

Place the potassium hydroxide in a porcelain crucible and heat it until it melts. Add the mixture of the sulphur and charcoal, which is previously prepared, to this. The potassium hydroxide reacts with the sulphur to produce a black substance in a plastic state. Stir well and knead it. The reaction may be as follows ... 

The addition of Cu to K/Fe oxides catalyst enhanced its ability of ethanol production. K/Cu-Fe oxides catalysts, prepared by kneading KjCO, with Cu-Fe co-precipitate, gave the ethanol selectivity of more than lOC-% at 300°C. The combination of K/Fe and Cu-Zn gave remarkable results on ethanol production. In the reaction over K/Cu-Zn-Fe oxides catalyst, CO2 conversion of 44% and ethanol selectivity of 20C-% were obtained under the standard reaction conditions. Besides ethanol, hydrocarbons were produced with a selectivity of almost 45C-%. The formation of hydrocarbons seems inevitable as long as Fe-based catalysts are employed. 

The reaction of solid fluorspar with liquid sulfuric acid produces a solid (calcium sulfate) and a gaseous (hydrogen fluoride) product. The reaction passes through a paste-like phase. Many reactor modifications have been developed to attain an optimal reaction in this phase. The aim is thorough mixing of this phase, which is achieved by internal fittings in the rotary tube (e.g. paddles) or by kneading the reaction mixture in a kneader. 

Formulation of poly (vinyl chloride) into sheet goods is often beset with color problems. The kneading process takes place in the presence of dibutyltin maleate to initiate cross-linking reactions. The presence of AMS dimer in the kneading process leads to less yellowing and better thermal stability for the PVC sheet.485... 

Keywords kneading ball milling, quantitative, condensation reaction, aldehydes, hydroxylamine, hydroxylamine, oximes... 

An analytical model based on the energy balance in CORI was proposed. Anionic polymerization of e-caprolactam in CORI was modeled, considering continuity of the process from one screw element to another. The model took into account the heat of reaction, viscous dissipation and heat transfer across the barrel. The calculations were performed for three different screw configurations comprising the transport and kneading elements. The predicted total conversion agreed with the experimental values within 3% [Kye and White, 1996]. 

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