Hydrogen the presence

I. Carbon and Hydrogen. The presence of these elements is usually assumed. If a direct test is required, a mixture of about 01 g. of the powdered substance and 2-3 g. of finely powdered copper oxide is heated in the tube A (Fig. 68) and the... 

With vinylketene adducts (2-vinylcyclobutanones) possessing an enolizable hydrogen, the presence of triethylamine used for generating the ketene will occasionally cause double-bond isomerization resulting in alkylidenecyclobutanones 22.138,139 These derivatives are not readily prepared by alkylideneketene to alkene cycloadditions because of the extreme reactivity towards dimerization of these ketenes. 

The synthesis of ethyl chloride from ethylene and hydrogen the presence of methane (inert) was studied in a differential Thodos Stutzman (Ind Eng Chem 50 413, 1958) over zirconium... 

Our previous results on hypericin indicate that excited-state H-atom transfer occurs even when one of the carbonyls is prohibited from accepting a hydrogen. The presence of such a transfer is apparent under very acidic conditions in AOT reverse micelles and cannot be excluded upon chelation of Tb3+ [76]. There is thus no evidence for a concerted H-atom-transfer mechanism in hypericin. In the present study, contrary to our initial expectations, we are not even able to demonstrate that hypomycin B executes an excited-state H-atom transfer hence our investigation sheds no light on the general question of how many H atoms are transferred in the perylene quinones and whether the transfer is concerted or stepwise. On the other hand, if further investigation reveals that H-atom transfer does not occur in hypomycin B, the result would have considerable implications for an understanding of the reaction coordinate for the H-atom transfer. 

Alkenes are said to be unsaturated because they are capable of adding hydrogen in the presence of a catalyst. The product, an alkane, is called saturated because it cannot react with any more hydrogen. The presence of a pi bond of an alkene (or an alkyne) or the ring of a cyclic compound decreases the number of hydrogen atoms in a molecular formula. These structural features are called elements of unsaturation. Each element of unsaturation corresponds to two fewer hydrogen atoms than in the saturated formula. 

An aliphatic dinitrile sebaconitrile has been converted to 1,10-decanediamine in 79-80% yields with addition of an 8 molar ratio of ammonia to the nitrile (7.20).34 In this hydrogenation, the presence of ammonia at least in 5 molar ratio to the nitrile was claimed to be necessary to minimize the formation of secondary amine. The hydrogenation of a number of dinitriles, including industrially important adiponitrile and m-... 

We determined the ratio of the magnetic moments of the proton and the deuteron with improved accuracy (37). We demonstrated that even thoroughly outgassed materials such as glass, quartz and metal wires retain a certain amount of hydrogen, the presence of which becomes evident by exchange with deuterium at elevated temperature (38). 

The presence of free-carbon solids has been noted in coal tars, and undoubtedly, there are unreacted coal particles present in the products from hydrogenation. The presence of solid particles increases viscosity, though there is supposedly little accompanying effect upon the viscosity-temperature susceptibility. 

A. Pullman I have three questions (1) Do you have any rationalization or hypothesis as to the role of the hydrogen the presence of which was found necessary for the effect ... 

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