Separation process for anhydrous HCl and HBr by thermal cleavage
US4830846A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 29, 1988 |
| Grant date | May 16, 1989 |
| Priority date | — |
| Expiry date | Jan 29, 2008 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC01B7/093
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A method for the separation of anhydrous HCl and HBr from mixtures of the two acids comprising treating the mixture with a hindered pyridine to form a mixture of hindered pyridine salts of the acids, and heating the mixture of salts to a temperature at which thermal cleavage of at least the hydrochloride salt is induced. The hindered pyridines are defined as aromatic compounds having one or more nitrogen atoms in an aromatic ring, or a polymer with pendant aromatic moieties having one or more nitrogens in an aromatic ring, having an appropriate degree of steric hindrance such that the salt formed by the nitrogen atom of the aromatic compound and a strong protic base will undergo dissociation to the aromatic compound and the protic acid at a temperature below the decomposition temperature of the aromatic compound. The formation of salts and their cleavage can be done as either a one-step or two-step process. The separation process is based on the fact that the HCl salts are less stable to heat than the HBr salts, and thus will cleave at a faster rate at any given temperature. It is possible to carry out the thermal cleavage at a temperature sufficient to induce cleavage of only the …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.