Acidic Hydrocarbons to Evolve

Class 1 The carbides of the more electropositive elements have many of the properties associated with ionic crystals. They form colourless, transparent crystals which at ordinary temperatures do not conduct electricity. They are decomposed by water or dilute acids, and since the negative ions are unstable, hydrocarbons are evolved. According to the type of ion present in the crystal we may divide these carbides into two main groups ... 

ITQ-2, a novel zeolitic structure prepared by swelling and delaminating a MWW precursor, has been studied by IR spectroscopy. The same precursor yields, when calcined, the zeolite MCM-22. Bronsted acidity has been measured as the propensity either to engage in H-bonds or to transfer the proton to unsaturated hydrocarbons. Comparison with MCM-22 shows that dealumination accompanies the process of delamination, but no appreciable change in residual Bronsted acidity takes place. Reaction of propene with Bronsted sites to branched oligomers occurs mainly on the external surface. Oligomers show no tendency to evolve to allylic cationic species, in contrast with MCM-22. 

The thermal decomposition of PA 6.6 is quite complex, and the products decomposed are affected by the temperature [57]. It was first reported that PA 6.6 eliminates cyclopentanone as the main decomposition product, but also some hydrocarbons, nitriles, and vinyl fragments [56], Wiloth [64] later suggested that the main mechanisms of thermal decomposition of PA 6.6 were based on the tendency of the adipic acid fragment to undergo cyclization. With the development of modern test methods, the thermal decomposition of PA 6.6 has been extensively investigated by mass spectrometry, IR spectrometry, evolved-gas analysis, and so forth. PA 6.6 fragments, hexamethylenediamine, ammonium, CO2, cyclopentanone, and many other products were detected [65-70]. 

Metallic sodium. This metal is employed for the drying of ethers and of saturated and aromatic hydrocarbons. The bulk of the water should first be removed from the liquid or solution by a preliminary drying with anhydrous calcium chloride or magnesium sulphate. Sodium is most effective in the form of fine wire, which is forced directly into the liquid by means of a sodium press (see under Ether, Section II,47,i) a large surface is thus presented to the liquid. It cannot be used for any compound with which it reacts or which is affected by alkalis or is easily subject to reduction (due to the hydrogen evolved during the dehydration), viz., alcohols, acids, esters, organic halides, ketones, aldehydes, and some amines. 

The procedure is to pass purified hydrogen through a hot solution of the pure acid chloride in toluene or xylene in the presence of the catalyst the exit gases are bubbled through water to absorb the hydrogen chloride, and the solution is titrated with standard alkali from time to time so that the reduction may be stopped when the theoretical quantity of hydrogen chloride has been evolved. Further reduction would lead to the corresponding alcohol and hydrocarbon ... 

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