Agglomerates of malachite crystals and method for their preparation
AssigneeE. I. DuPont de Nemours and Company
InventorJoseph M. Fremont
Life of this patent
Estimating the term…
Abstract
Agglomerates of spheroidal masses of malachite crystals are prepared so that they contain silicic acid. These agglomerates can be used to prepare a copper-acetylide complex, which in turn can be used as a catalyst for the preparation of 1,4-butynediol from acetylene and formaldehyde.
Claims5
An agglomerate of spheroidal masses of malachite crystals, which crystals comprise 1-7% by weight, of bismuth oxycarbonate and 0.5-3.5%, by weight (calculated as SiO.sub.2) of silicic acid.
A process for preparing agglomerates of spheroidal masses of malachite crystals, which crystals comprise 1-7%, by weight, of bismuth oxycarbonate and 0.5-3.5%, by weight (calculated as SiO.sub.2), of silicic acid from a copper salt, a bismuth salt and silicic acid, the process comprising
- (a) forming amorphous gel-like hydrated copper carbonate by bringing together, in aqueous solution, with agitation, at a temperature of about 45.degree.-55.degree. C., and at a pH of 5.5-7.5, maintained with an alkali metal carbonate or an alkali metal bicarbonate, about 30-60% by volume of the total amounts of the copper salt, the bismuth salt and the silicic acid required to form the malachite and to provide the specified amounts of bismuth oxycarbonate and silicic acid;
- (b) holding the mass of (a), without agitation, at a temperature of about 45.degree.-55.degree. C. until masses of malachite crystals form;
- (c) and then maintaining the resulting slurry at a temperature of 45.degree.-55.degree. C., and a pH of 5.5-7.5 with an alkali metal carbonate or an alkali metal bicarbonate, while adding, with agitation, the remainder of the required amount of copper salt, bismuth salt and silicic acid,
- to form the agglomerates.
Dependencies are inferred from the claim text.