Acetylene preparation

Mercuric oxide (5 g.) is dissolved for the most part in a still warm mixture of 110 c.c. of water and 50 c.c. of concentrated sulphuric acid. The mixture is brought into a large hydrogenation flask (Fig. 58, p. 377) and shaken for some time with acetylene prepared from calcium carbide, purified with acid solutions of dichromate and copper nitrate, and collected over saturated sodium chloride solution in a glass gas-holder (capacity 10-15 litres). Before shaking is begun the air present must be displaced by the hydrocarbon. 

Acetylene prepared from calcium carbide and purified by passing (1) through copper sulphate solution, and (2) through a tower packed... 

Table 7 shows the H3 binding data of the acetylenes prepared in the study. The acetylenes GT-2293 and GT-2286 were the most potent compounds prepared. GT-2286 crosses the blood-brain barrier efficiently, exhibiting a 50% H3 cortical receptor occupancy level at 60 minutes with an ip dose of between 0.3-1.0 mg/kg in rats. 

Dehydrohalogenation Benzyltrimethylammonium mcsitoate. r-Butylamine. Calcium carbonate. j Uidine. Diazabicyclo[3.4.0]nonene-5. N.N-Dimethylaniline (see also Ethoxy-acetylene, preparation). N,N-Dimelhylformamide. Dimethyl sulfoxide-Potassium r-but-oxide. Dimethyl sulfoxide-Sodium bicarbonate. 2,4-Dinitrophenylhydrazine. Ethoxy-carbonylhydrazine. Ethyldicyclohexylamine. Ethyidiisopropylamine. Ion-exchange resins. Lithium. Lithium carbonate. Lithium carbonate-Lithium bromide. Lithium chloride. Methanolic KOH (see DimethylTormamide). N-PhenylmorphoKne. Potassium amide. Potassium r-butoxide. Pyridine. Quinoline. Rhodium-Alumina. Silver oxide. Sodium acetate-Acetonitrile (see Tetrachlorocyclopentadienone, preparation). Sodium amide. Sodium 2-butylcyclohexoxide. Sodium ethoxide (see l-Ethoxybutene-l-yne-3, preparation). Sodium hydride. Sodium iodide in 1,2-dimethoxyethane (see Tetrachlorocyclopentadienone, alternative preparation) Tetraethylammonium chloride. Tri-n-butylamine. Triethylamine. Tri-methyiamine (see Boron trichloride). Trimethyl phosphite. 

NOTES.—(a) The acetylene prepared in this way from commercial calcium carbide contains impurities, such as hydrogen sulphide and phosphine. If the gas is to be used to prepare other compounds, it should be purified by passing it through a wash-bottle containing a solution of mercuric chloride in hydrochloric acid. 

In some forms of generators for the gas, which are used commercially, the finely powdered carbide runs slowly into a reservoir of water. A better regulation of the gas supply is effected by using this method, and overheating, which may lead to an explosion, is avoided. Acetylene prepared from commercial calcium carbide contains ammonia, hydrogen sulphide, and phosphine. These substances must be removed when the gas is to be used for indoor illumination. The purification is effected by washing the gas with water and a mixture of slaked lime and bleaching powder, or with a solution of chromic acid in hydrochloric acid. In the laboratory a solution of mercuric chloride in dilute hydrochloric acid can be conveniently used for the purpose. 

As shown in Table 3, cis- and trans-coni nU of poly acetylene prepared by the Ziegler-Natta catalysts depends strongly upon the polymerization temperature ss x ere are two possible explanations for this observation One is that the fundamental mechanism is the formation of cis double bonds by the cis insertion of acetylene monomer into the Ti—C bond of the catalyst. This fits the orbital interaction consideration for the role of the catalyst by Fukui and Inagaki, according to which the initially formed configuration of the double bond is cis as a result of the favorable orbital interaction between the inserting acetylene monomer and the active site of the catalyst. Because the cis double bond is thermodynami-... 

Tabata, M. Sone, T. Mawatari, Y Yonemoto, D. Miyasaka, A. Fukushima, T. Sadahiro, Y. 3T-Conjugated columnar poly acetylenes prepared with Rh complex catalyst. Macromol. Symp. 2003, 192, 75-97. 

MeOH and Si react directly on a fluid bed to give (MeO)3SiH and (MeO>4Si, M(CO)2(dmpe)2Cl on reductive silylation gives the bissiloxy alkyne derivative which acidifies to the first dihydroxyacetylene complex, and silyl acetylenes prepared regioselective. The relative stability of ketene and silaketene radical cations are compared and ketene thermally eliminated from ethyl silyl acetates. ... 

Table 4. Comparison of samples of poly(acetylene) prepared by Shirakawa s ("S") and Luttinger s ("L") method with regard to their conductivity after doping under exactly the same conditions...

The ring inversion barrier for (46 /i = 2) was measured (n.m.r.) and found to be 75 kJ mol an Jf-ray structure determination of this compoimdhas been reported, together with that of l,8-bis(propyn-l -yl)naphthalene. Other acetylenes prepared include a-ethynylamines (47) from the corresponding alcohols acetylenic ethers or tertiary amines (48) by reaction of... 

He showed that sodium salts of aliphatic primary and secondary nitrocompounds react with adds to form carbonyl compounds zRsCHNOs =2RyCO+N30 + H30. Nef supported the theory of bivalent carbon. In the pteparation of the explosive mercuric salt of nitromethane, he found that mercury fulminate is formed and regarded fiilminic acid as C N-OH, the reaction being Hg(CH, N0 0)3=Hg(0 N C)3+2H20. He prepared the explosive addition compound of fiilminic acid and hydrogen chloride, HONtCHQ. In researches on acetylene prepared explosive... 

Scheme 4.1 Substituted acetylenes prepared from l,2-di(trimethylstannyl)-acetylene.

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