Mercuric oxide acetylenes

The hydration of triple bonds is generally carried out with mercuric ion salts (often the sulfate or acetate) as catalysts. Mercuric oxide in the presence of an acid is also a common reagent. Since the addition follows Markovnikov s rule, only acetylene gives an aldehyde. All other triple-bond compounds give ketones (for a method of reversing the orientation for terminal alkynes, see 15-16). With allqmes of the form RC=CH methyl ketones are formed almost exclusively, but with RC=CR both possible products are usually obtained. The reaction can be conveniently carried out with a catalyst prepared by impregnating mercuric oxide onto Nafion-H (a superacidic perfluorinated resinsulfonic acid). ... 

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. 

Source Manufactured by oxidizing ethanol with sodium dichromate and sulfuric acid or from acetylene, dilute sulfuric acid, and mercuric oxide catalyst. 

Moureu investigated the addition of alcohols, catalyzed by sodium methoxide, to acetylenic esters and has shown that enol ethers are formed as primary adducts. It has been shown that compounds such as potassium cyanide, a mixture of mercuric oxide, boron trifluoride,... 

Explosive reaction with acetylene, antimony powder, hafnium powder + heat, tetraamine copper(II) sulfate + ethanol, trioxygen difluoride (possibly ignition), polyacetylene (at 113°C). Forms sensitive, explosive mixtures with potassium (impact-and heat-sensitive), sodium (shock-sensitive), oxygen difluoride (heat-sensitive). Reacts to form explosive products with ammonia, ammonia + Uthium 1-heptynide, ammonia + potassium, butadiene + ethanol + mercuric oxide, silver azide. 

Acetylene is condensed to vinylacetylene and divinylacetylene by cuprous chloride and ammonium chloride. Similar additions of other compounds containing an active hydrogen atom occur in the presence of various catalysts. Mercury salts ate most effective in the vapor-phase reaction of acetylene with hydrogen chloride to give vinyl chloride (100%). Basic catalysts such as potassium hydroxide, potassium ethoxide, or zinc oxide are used for the vinylation of alcohols, glycols, amines, and acids. Most of these reactions involve the use of acetylene under pressure, and few have been described as simple laboratory procedures. Chloroacetic acid, however, reacts with acetylene at atmospheric pressure in the presence of mercuric oxide to yield vinyl chloro-acetate (49%). ... 

Acetals are formed by the action of acetylene with alcohols in the presence of a catalyst consisting of boron trifluoride and mercuric oxide. The method has been extended to the condensation of substituted acetylenes, RC s CH, with alcohols to give ketals, as illustrated by the preparation of 2-hexanone dimethyl ketal (70%). The acidic catalyst must be carefully neutralized with powdered anhydrous potassium carbonate before contacting the acetal or ketal with water. 

The reaction of 1,2-dibromocycloalkenes (13) with magnesium in the presence of l,3-diphenylbenzo[c]furan (16) affords a cycloalkyne adduct (17). Also, the mercuric oxide oxidation of bishydrazone, which has been used extensively in the preparation of open-chain and medium or large cyclic acetylenes " , is adapted for small ring bishydrazones (18) . Treatment of 18 with mercuric oxide in the presence of 16 or of phenyl azide results in the adducts, 17 and 19, respectively. It seems... 

Mercuric oxide, HgO (yellow modification or the less reactive red modification), resembles silver oxide in its oxidizing properties. This reagent transforms phenols and hydroquinones into quinones [383, 384] and is used especially for the conversion of hydrazones into diazo compounds [355, 386, 387, 388, 389, 390, 391, 392]. Dihydrazones of a-diketones furnish acetylenes [393, 394, 395, 396], A -Aminopiperidines are dehydrogenated to tetrazenes [397] or converted into hydrocarbons [395]. 

Ketone derivatives whose oxidations have wide applications in synthesis are hydrazones and vicinal dihydrazones. Hydrazones are transformed into diazo compounds, and vicinal dihydrazones are converted into acetylenes. By far the most widely used oxidant is yellow mercuric oxide... 

Dihydrazones of a-diketones, when treated with mercuric oxide at higher temperatures, yield acetylenes [393, 394, 395, 396], Diphenylacet-ylene is obtained by refluxing benzil dihydrazone with mercuric oxide [396] in benzene or by refluxing benzil monohydrazone with mercurous trifluo-roacetate in ether for 2 h (yield 43%) [405], The oxidation of dihydrazones... 

From Mercuric Oxide. —yVhm acetylene is passed through a suspension of mercuric oxide in boiling phosphoric acid, density 1-15, or in 30 per cent, sulphuric acid, acetaldehyde is produced. 

Hydration of acetylenes. Dowex-50 itself is not an efficient catalyst for hydration of an acetylene, but Newman" prepared an excellent catalyst for this reaction by impregnating the resin with 1% mercuric sulfate (by treatment with mercuric oxide... 

Catalyst for addition to acetylenes. The conversion of 1-ethynylcyclohexanol to 1-acetylcyclohexanol by hydration of the triple bond is accomplished by dissolving 5 g. of Mallinckrodt red mercuric oxide in a solution of 8 ml. of coned, sulfuric... 

Vinyl ehloroacetate is obtained by catalyzed addition of chloroacetie acid to acetylene. A mixture of 2.12 moles of chloroacetie acid (m.p. 63°), 0.2 g. of hydro-quinone (polymerization inhibitor), and 20 g. of yellow mercuric oxide is stirred and... 

Acetylenes, hydration Mercuric oxide. Mercury p-toluenesulfonamide. 

ACETIC ACID, COBALT(II) SALT (71-48-7) Co(CjH30j)i 4HOH Noncombustible solid. Solution in water is basic (pH 6.8 to >7.0) reacts with acids. Some cobalt compounds react with oxidizers, acetylene. Cobalt is a known animal carcinogen. ACETIC ACID, CUPRIC SALT (142-71-2) Cu(C2H302)i H20 Noncombustible solid. Solution in water is basic reacts with acids. Incompatible with acetylides, hydrazine, nitromethane, mercurous chloride nitrates, sodium hypobromite. Thermal decomposition releases fumes of copper, acetic acid, and carbon oxides. 

These adducts must not be confused with mercury acetyleides, which have the structure (RC=C)2Hg and are obtained from mercuric oxide and the acetylene RC=CH. 

Curtius et ah206 showed that acetylenes can also be prepared by oxidizing vicinal dihydrazones with yellow mercuric oxide. Diphenylacetylene, for example, is thus obtained in 75% yield from benzil dihydrazone.207 In a variant of the Curtius procedure diacetylenes can be prepared in 80-85% yield by oxi-... 

Certain cyclic acetylenic compounds can also be synthesized by this method, e.g., cyclodecyne209 in 36% yield by oxidation of 1,2-cyclodecanedione di-hydrazone with yellow mercuric oxide in benzene containing ethanolic potassium hydroxide solution and anhydrous sodium sulfate and cyclodecyne has been obtained similarly.210... 

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