Acetylene, hydration

Acetylenes, hydration, 20 "Acid", 476 Additive effects of substituents, 179 Adrenalin, 38 Adrenalone, 38 Adrenergic agents, 36, 37 Adrenergic agonists, SAR, 37, 38, 251... 

The hydration of acetylene is catalysed by transition metal ions as Cu, Ag, Zn, Cd, Hg being either in aqueous solution or in form of oxides, phosphates, tungstates [1-3], Mentioned late transition metal ions in cationic positions of zeohtes were shown to have the best catalytic performance [4,5], Acetylene hydration seems to be appropriate test reaction for investigating the late transition metal forms of zeohtes. 

The reagent, usually in combination with a strong acid, is used as catalyst for effecting additions to acetylenes. Hydration of the acetylenic glycol (1) is effected by adding 25 g. of the finely powdered material within 20 min. to a vigorously... 

Acetylenes, hydration Mercuric oxide. Mercury p-toluenesulfonamide. 

Acetylene hydration can also, be achieved by producing methyl vinyl ether as an intermediate, which is then hydrolysed to methanol and acetaldehyde. The following... 

Table S. 1 gives economic data on the production of acetaldehyde by acetylene hydration and liquid phase oxidation of ethylene according to the Wacker-Hoechst (single-step and two-step) technologies.

Other references related to the Kutscheroff acetylene hydration are cited in the literature. ... 

When we turn to energetic aspects, acetylene hydration and ethylene oxidation have already been discussed in section 12.3.3.1. The appropriate energy input for fermentation ethanol is somewhat difficult to establish (see section 12.7.1.), but for the hydration of ethylene and subsequent oxidation of synthetic ethanol (in modern plants) we have ... 

Solid-state heteropoly compounds have interesting catalytic properties [117] and have found applications in olefin and acetylene hydration and alcohol dehydration [90fj. Adsorption of nonpolar molecules (hydrocarbons) reaches saturation at amounts lower than monolayers ("surface-type" adsorption). However, it is characteristic of heteropoly compounds that adsorption of polar molecules (alcohols, ethers, amines) takes place in amounts that exceed by many times (10-10 ) mono-... 

New mixed polyfunctional catalysts for acetylene hydration to produce acetaldehyde and acetone have been developed. ... 

When acetylene hydrate occurs in the equipment of an acetylene plant, especially in decomposition barriers and other safety accesories, it is less the danger of explosion than the blockage of the gas paths through the waxy mass that has to be taken into consideration. 

The most synthetically valuable method for converting acetylenes to ketones is by mercuric-ion-catalyzed hydration. Terminal alkynes give methyl ketones in good yields. Unsymmetrical internal alkynes give a mixture of two possible ketones in the absence of some special stabilizing feature. Scheme 4.6 gives some examples of acetylene hydrations. 

The most unexpected by-product of the reaction in this case is 2,3,6-triphenylpyridine. Probably, benzyl phenyl ketone (the usual product of partial deoximation of oximes in the conditions for synthesis of pyrroles) condenses with acetaldehyde (product of acetylene hydration in superbase media [105], Equation 1, Scheme 1.166) to form an equilibrium mixture of ethylenic ketones I and J (Equation 2). The ketone J reacts with benzylamine to close 2,3,6-triphenyltetrahydropyridine cycle K. The latter aromatizes to the pyridine (Equation 3). 

Probably, acetaldehyde, forming due to acetylene hydration, is condensed with pyrrole (though such condensation in the basic medium is unusual). 

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