Acetylene magnesium chloride

The temperature reaches 15°C after 0.5 hr, and 20°C after 0.8 hr. Ethynylmagnesium halides can rapidly disproportionate to bis(chloromagnesium)-acetylene and acetylene at higher temperatures. It is important to maintain the reaction mixture at or below 20°C and to have an excess of acetylene in order to prevent formation of the bis(magnesium chloride). The checkers found that the ethynylmagnesium chloride can be formed at 10-15°C, thus minimizing the problem. 

Zettner and Seligson (Z3) conducted an extensive study of calcium interferences deriving from serum constituents and other substances. In the air-acetylene flame, no effect was seen from excess concentrations of the ions of potassium, ammonium, magnesium, chloride, bicarbonate, and hydroxide. Phosphate, sulfate, oxalate, and EDTA acted as strong anionic depressors. Sodium caused a small but distinct depression of... 

CHgCiC.Cl. It was obtd in small quantity, mixed with ethyl bromide, by interaction of p-toluenesulfonyl chloride with methyl acetylene -magnesium bromide in dibutyl ether. It was not purified. The pure compd, bp 32 8-33° nDl 4l31 at 20°,. was prepd by dehydrohalogenation of cis -1,2-dichloro-l-propene or by chlorination of 1 -propyne (Ref 3)... 

Acetylenic ketones can be prepared in moderate yield by the reaction of acetylenic Grignard reagents with acid chlorides or anhydrides [Eq. (41) 75-78]. Alkynyl magnesium chloride reacts with acetic anhydride to give acetylenic ketones in good yield (see Table 4, entry 17). 

The rate of the reaction decreases with increasing number of substituents in the acetylenic halide, and it is higher with acetylenic bromides than with the corresponding chlorides. Methyl magnesium iodide gives equal amounts of 1,1- and 1,3--substitution products, whereas tert.-butylmagnesium bromide does not react. However, for some tert.-butyl substituted allenes there exists an attractive com-... 

A mixture of 0.30 mol of the tertiairy acetylenic alcohol, 0.35 mol of acetyl chloride (freshly distilled) and 0.35 mol of /V/V-diethylaniline was gradually heated with manual swirling. At 40-50°C an exothermic reaction started and the temperature rose in a few minutes to 120°C. It was kept at that level by occasional cooling. After the exothermic reaction had subsided, the mixture was heated for an additional 10 min at 125-130°C, during which the mixture was swirled by hand so that the salt that had been deposited on the glass wall was redissolved. After cooling to below 50°C a mixture of 5 ml of 36% HCl and 200 ml of ice-water was added and the obtained solution was extracted with small portions of diethyl ether. The ethereal solutions were washed with water and subsequently dried over magnesium sulfate. The solvent was removed by evaporation in a water-pump vacuum... 

A mixture of 0.10 mol of the acetylenic alcohol, 0.12 mol of triethylamine and 200 ml of dichloromethane (note 1) was cooled to -50°C. Methanesulfinyl chloride (0.12 mol) (for its preparation from CH3SSCH3, (08300)30 and chlorine, see Ref. 73) was added in 10 min at -40 to -50°0. A white precipitate was formed immediately. After the addition the cooling bath was removed and the temperature was allowed to rise to -20°0, then the mixture was vigorously shaken or stirred with 100 ml of water. The lower layer was separated off and the aqueous layer was extracted twice with 10-ml portions of CH2CI2. The combined solutions were dried over magnesium sulfate and concentrated in a water-pump vacuum (note 2). The yields of the products, which are pure enough (usually 96%) for further conversions, are normally almost quantitative. 

The determination of magnesium in potable water is very straightforward very few interferences are encountered when using an acetylene-air flame. The determination of calcium is however more complicated many chemical interferences are encountered in the acetylene-air flame and the use of releasing agents such as strontium chloride, lanthanum chloride, or EDTA is necessary. Using the hotter acetylene-nitrous oxide flame the only significant interference arises from the ionisation of calcium, and under these conditions an ionisation buffer such as potassium chloride is added to the test solutions. 

Coupling of acetylenes and halides, copper-promoted, 50,100 Cuprous chloride, reaction with an organo-magnesium compound, 50,98... 

Diethyl ether, Dichloromethylphosphine, Ethyl alcohol, N,N-Diethylamine, 2-Dimethylaminomethanol, Rhombic sulfur Acetylene, Arsenic trichloride. Aluminum chloride Acetylene, Arsenic trichloride. Mercuric chloride, Hydrochloric acid Methylene chloride. Magnesium metal turnings, Tetrahydrofuran, Arsenic trichloride, Hexanes... 

Sodium azide, Lead acetate, Water Picric acid. Sodium hydroxide. Lead nitrate Styphinic acid. Sodium hydroxide, Lead-II-nitrate Styphinic acid. Magnesium carbonate. Lead nitrate. Nitric acid Phloroglucinol, Glacial acetic acid. Sodium nitrite. Lead nitrate Acetylene, Arsenic trichloride. Mercuric chloride. Hydrochloric acid... 

Treating l-chloro-l-(trichlorovinyl)cyclopropanes with three equivalents of BuLi afforded the the dilithiated acetylene This, upon reaction with excess trimethylsilyl chloride, yielded the bis(trimethylsilyl)ethynylcyclopropane (equation 163). The same results can be achieved using magnesium metal in THF as the metallating agent, instead of the preferable BuLi236 238. 

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