Formation of caking coals
US4259167A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 23, 1979 |
| Grant date | Mar 31, 1981 |
| Priority date | — |
| Expiry date | Aug 23, 1999 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC10G1/00
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
Highly caking coals are formed by selective oxygen-alkylation or oxygen-acylation of moderately, weakly or non-caking coals, employing a phase transfer reaction which chemically alters phenolic and carboxylic functional substituents. These two very polar functional groups are converted to relatively non-polar ethers and esters, respectively. The O-alkylation or O-acylation is carried out in a binary liquid phase solution (organic and water phases with a solid phase suspended in the medium). A quaternary ammonium or phosphonium salt is reacted with alkali or alkaline earth base to produce the corresponding quaternary ammonium or phosphonium base (an example of a phase transfer reagent). This quaternary base is non-nucleophilic and readily removes the phenolic and carboxylic protons but does little else to the coal structures. After the removal of the weakly acidic protons by the quaternary base, the phenoxides and carboxylates which are produced then undergo O-alkylation or O-acylation. The alkylating or acylating agent comprises a carbon-bearing functional group and a displaceable leaving group. The process of the invention produces caking properties in non-caking subbituminous coa…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.