Liquid Acetylene. Reaction System for Safe Operation under Pressure

Liquid Acetylene. Ethynylation Studies and the Formation of Transition Metal Complexes

“…Apparatus. A reaction system for safely liquefying and handling acetylene has been described (Tedeschi et al, 1968). The reactors used in the following experiments were either a 125-cc stirred autoclave equipped with jacketed walls through which a heat exchange fluid (methanol) was circulated to control the reactor temperature or a sight-glass reactor suspended in a bath for temperature control and gently rocked back and forth to agitate the reaction mixtures contained therein.…”

“…The base-catalyzed ethynylation of aldehydes and ketones to ethynyl carbinols in donor solvents has been shown (Tedeschi, 1965; Tedeschi et al, 1963a,b) to involve the intermediate formation of complexes comprising (A) acetylene-solvent, (B) acetylene-alkali metal hydroxide, and (C) ethynyl carbinol-alkali metal hydroxide. Complexes of B and C have been isolated and studied (Tedeschi et al, 1963a,b), while solubility studies at atmospheric and elevated pressures (Tedeschi et al, 1968) confirm the existence of A. The key species in the catalytic ethynylation of acetone is the base adduct of 3-methyll-butyn-3-ol (MB-KOH complex).…”

“…9, No. (Tedeschi et al, 1968) in all runs except 3, in which a stirred autoclave was used. ' Used 0.010 mole of MB-KOH complex as catalyst and 5 cc (0.052 mole) of methyl butynol as solvent for complex.…”

“…This species is always formed in situ in any ethynylation involving alkali hydroxides, with the exception of lithium hydroxide (Tedeschi et al, 1963a(Tedeschi et al, ,b, 1965. The latter, although capable of forming a LiOH-C2H2 complex in liquid acetylene (Tedeschi et al, 1968), does not react with acetone, even in liquid ammonia, to form the prerequisite MB-LiOH adduct.…”

“…Transition metal complexes of nickel, copper, molybdenum, and palladium compounds were readily formed by reaction with excess liquid acetylene. gARLiER work has shown that liquid acetylene can be handled safely in a properly designed pressure system (Tedeschi et al, 1968) and that the liquefied gas can be effectively used in the formation of alkali metal acetylides and sodium propicíate (H-C = C-C02Na) (Tedeschi and Moore, 1969). Additional studies reported in this paper deal with the catalytic ethynylation of carbonyl compounds and amines and the formation of transition metal complexes in excess liquid acetylene.…”