On the nature of transformation reactions of unsaturated glycols on the nickel cathode

Abstract

: The catalytic nature of the process of cathodic hydrogenation of the unsaturated bond has been determined by evaluating radiometrically the inÑu-ence of addition of di †erent quantities of 63Ni to the supporting solution free from nickel ions on the unsaturated bond hydrogenation rate. The catalytic activity of a nickel cathode used to hydrogenate 2-butynediol-1,4 labelled by a 14C isotope is approximately four times higher in a nickel-plating electrolyte than that in an electrolyte free from nickel ions. Electrolysis conditions determine the extent of triple bond reduction, the quantity of unsaturated glycols in the coating and its physical and mechanical properties. When using the mixture of acetylenic and ethylenic glycols, a bright, highly plastic (to 6%) coating is deposited from the nickel-plating electrolyte. The intermediate ethylene may be quantitatively synthesised in the nickel-plating bath.

Influence of the Composition of Dilute Nickel-Plating Electrolytes on the Physicomechanical Properties of Electroplated Coatings

“…The plasticity of a lustrous nickel coating formed under the same conditions reaches a value of 9% (Fig. 1b), which is very high, compared with that obtained previously (up to 6%) for the technological solutions suggested in [9]. It should be noted that sufficiently plastic deposits (6%) are also obtained from dilute nickel-plating electrolyte nos.…”

“…The table lists the electrolyte formulations and estimates of the nickel-plating rates, found by the fast method [5] with a Hull cell. The formulation suggested is similar to the technological solution of [9], which consists in that small concentrations of YN are used in combination with an ethylene compound, EN, with the key role played by the competition of acetylene and ethylene groups in hydrogenation. b-Oxyethyl cinnamide is described by the formula C 6 H 5 CH=CH3CONHCH 2 CH 2 OH and, unlike EN, contains a phenyl radical and nitrogen.…”

“…b-Oxyethyl cinnamide is described by the formula C 6 H 5 CH=CH3CONHCH 2 CH 2 OH and, unlike EN, contains a phenyl radical and nitrogen. A comparative study of the known bright-nickel-plating electrolyte based on a mixture of YN and EN [9] in an untypical formulation of a dilute electrolyte no. 2 demonstrated that the rates of metal plating in a dilute chloride solution differ only slightly for the additives used.…”

“…The considerable increase in the hydrogenation of the deposits deteriorates the physicomechanical properties of the coatings obtained [6 3 8]. To improve the main characteristics of the bright-nickel-plating process, acetylene compounds are used in combination with ethylene and organosulfur additives [9].The aim of this study, was to assess the influence exerted by the composition of a dilute nickel-plating electrolyte containing luster-forming additives based on b-oxyethyl cinnamide (OECAM) on the physicomechanical properties of the coatings being deposited. …”

“…The considerable increase in the hydrogenation of the deposits deteriorates the physicomechanical properties of the coatings obtained [6 3 8]. To improve the main characteristics of the bright-nickel-plating process, acetylene compounds are used in combination with ethylene and organosulfur additives [9].…”