Malachite preparation
AssigneeE. I. Du Pont de Nemours and Company
InventorJoseph Melvin Fremont
Life of this patent
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Abstract
Synthetic malachite of desirable particle size and distritution is coprecipitated with small amounts of uniformly dispersed bismuth. After nucleation, the crystals are grown at elevated temperatures. The malachite can be converted into a cuprous acetylide complex useful as an ethynylation catalyst.
Claims18
A process for the production of agglomerates of crystalline particles of basic copper carbonate having uniformly dispersed therein bismuth in amounts in the range of 2 to 5 percent by weight based on the amount of copper present, said process consisting essentially of the following steps:
- precipitating hydrated copper carbonate particles by the addition to water of solutions of cupric salts and alkali metal carbonate or bicarbonate to form a reaction mixture, said solutions being in such proportions as to maintain the pH about in the range of 5.0 to 8.0,
- nucleating and converting the hydrated copper carbonate to basic copper carbonate in the reaction mixture at a temperature of at least about 60.degree. C., and
- growing agglomerates of the nucleated crystalline particles by precipitating basic copper carbonate containing bismuth by the addition to the reaction mixture of solutions of cupric salts, bismuth salts and alkali metal carbonate or bicarbonate in such proportions as to maintain the Ph about in the range of 5.0 to 8.0 with the reaction mixture at a temperature of at least about 60.degree. C. until the average cross-sectional dimension of the agglomerates of crystallites is at least about 10 microns.
A process for the production of a particulate cuprous acetylide complex having uniformly dispersed therein bismuth in the amount of 2 to 5 percent by weight based on the amount of copper present, said process consisting essentially of the following steps:
- precipitating hydrated copper carbonate particles by the addition to water of solutions of cupric salts and alkali metal carbonate or bicarbonate to form a reaction mixture, said solutions being in such proportions as to maintain the pH about in the range of 5.0 to 8.0,
- nucleating and converting the hydrated copper carbonate to basic copper carbonate in the reaction mixture at a temperature of at least about 60.degree. C., and
- growing agglomerates of the nucleated crystalline particles by precipitating basic copper carbonate containing bismuth by the addition to the reaction mixture of solutions of cupric salts, bismuth salts and alkali metal carbonate or bicarbonate in such proportions as to maintain the pH about in the range of 5.0 to 8.0 with the reaction mixture at a temperature of at least about 60.degree. C. until the average cross-sectional dimension of the agglomerates of crystallites is at least about 10 microns, and then
- subjecting the agglomerated basic copper carbonate as a slurry in aqueous medium at 50.degree. to 120.degree. C., to the simultaneous action of formaldehyde and acetylene at partial pressure of not more than 2 atmospheres, said aqueous medium having a pH of 3 to 10 at the initiation of said subjecting, and continuing the reaction until said complex is obtained.
Dependencies are inferred from the claim text.