Isomerization and separation of cymenes from mixtures containing same
US3962366A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 5, 1974 |
| Grant date | Jun 8, 1976 |
| Priority date | — |
| Expiry date | Aug 5, 1994 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C7/152
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
The invention concerns an improvement in the process of isomerization and separation of ortho-, meta- and para-cymenes from mixtures containing same by contacting said mixtures with HF and BF.sub.3 at low temperatures in order to form a preferential complex with the meta-cymene, said improvement comprising the steps of: PA1 A. contacting the mixture to be treated containing the ortho-, meta- and para-cymenes with 4 to 50 molecules of HF for 1 mol of total cymenes and 0.5 to 3 mols of BF.sub.3 for 1 mol of metacymene present in this mixture; PA1 B. controlling of the rates of isomerization governed by the following equations (1), (2), and (3) EQU o-cymene .revreaction. m-cymene (1) EQU o-cymene .revreaction. p-cymene (2) EQU p-cymene .revreaction. m-cymene (3) and the rate of the following transalkylation reaction (4) EQU 2 cymenes .revreaction. 1 toluene + 1 di-isopropyl-toluene (4) by utilizing both low temperatures between a temperature lower than -50.degree.C. and a temperature lower than -5.degree.C. and toluene added; PA1 C. allowing the reaction medium resulting from steps (a) and (b) to decantate in order to obtain two phases, an upper phase or raffinate fraction containing …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.