http://rdf.ncbi.nlm.nih.gov/pubchem/patent/GB-809186-A
Outgoing Links
| Predicate | Object |
|---|---|
| assignee | http://rdf.ncbi.nlm.nih.gov/pubchem/patentassignee/MD5_5bb89ee4c7370d063635e913bc926c49 |
| classificationCPCInventive | http://rdf.ncbi.nlm.nih.gov/pubchem/patentcpc/C07C17-35 |
| classificationIPCInventive | http://rdf.ncbi.nlm.nih.gov/pubchem/patentipc/C07C17-00 |
| filingDate | 1957-04-26-04:00^^<http://www.w3.org/2001/XMLSchema#date> |
| publicationDate | 1959-02-18-04:00^^<http://www.w3.org/2001/XMLSchema#date> |
| publicationNumber | GB-809186-A |
| titleOfInvention | A process of preparing unsaturated aromatic halogen compounds |
| abstract | Omega-halostyrene, homologues thereof and halo indenes are prepared by pyrolysis of the boric ester of the corresponding halohydrin, preferably in vacuo. The boric esters may be prepared by known methods, e.g. by heating the halohydrin with boric acid or boron oxides. Preferably a catalytic amount of a suitable inhibitor such as hydroquinone is added. The molar ratio of halohydrin to boric acid should preferably be a little less than 1 : 1. Either crude or pure halohydrins may be used as the starting material. Any impurities present may be removed during the formation of the boric esters and before pyrolysis if required. The process of the invention may be carried out by introducing boric acid together with the halohydrin into a normal vacuum distillation equipment and heating the mixture slowly in vacuo while distilling off the water formed. The heating is continued until the halostyrene or haloindene distills off. Temperatures for the pyrolysis above 150 DEG C., and a vacuum of 15 to 18 tons give favourable results. Suitable compounds to which the method may be applied are those in which an aromatic system is connected to a chain of at least two carbon atoms of which the former carries an hydroxyl group and the latter a halogen atom. Examples are given of the preparation of omega bromostyrene from styrene bromohydrin and boric acid, 4-methyl-omega-bromostyrene from 4-methylstyrene bromohydrin and boric acid, 2-bromo-indene from indene bromohydrin and boric acid, omega bromostyrene from styrene bromohydrin and boron trioxide, and omega-chlorostyrene from styrene chlorohydrin and boric acid. All the examples are carried out in the presence of hydroquinone. Specifications 746,042 and 746,043 are referred to. |
| priorityDate | 1956-05-02-04:00^^<http://www.w3.org/2001/XMLSchema#date> |
| type | http://data.epo.org/linked-data/def/patent/Publication |
Incoming Links
Total number of triples: 38.