GB752146A - Improvements in light sensitive colour photographic materials - Google Patents

Abstract

2-Caprylylhydroquinone is prepared by passing boron trifluoride gas into a slurry of hydroquinone, n-caprylic acid and tetrachloroethane. The product is reduced in acetic acid solution by hydrogen under pressure and in the presence of palladium on charcoal catalyst to give 2-n-octylhydroquinone. A second caprylyl group may be introduced in a similar manner to give 2 - caprylyl - 5 - n - octylhydroquinone and this may be similarly reduced to give 2:5-di-n-octylhydroquinone. Similarly, 2 - n - dodecylhydroquinone is treated with lauric acid and boron trifluoride to give 2-n-dodecyl-5-laurylhydroquinone and this is then reduced with hydrogen to give 2:5-di-n-dodecylhydroquinone. 2-Caprylyl-4-methoxyphenol is prepared by passing boron trifluoride into a mixture of p-methoxyphenol and caprylic acid. Reduction as above with hydrogen and palladium on charcoal catalyst yields 4-methoxy-2-n-octylphenol. Introduction of a second caprylyl group in similar manner gives 2-caprylyl-4-methoxy-6-n-octylphenol and reduction gives 2:6-di-n-octyl-4-methoxyphenol. 2:6 - Di - n - octylhydroquinone is prepared by refluxing 2:6-di-n-octyl-4-methoxyphenol in glacial acetic acid with hydrobromic acid. It may also be prepared by reducing 2:6-di-n-octylquinone with zinc dust in acetic acid. 2:6-Di-n-octylquinone is prepared by oxidizing an aqueous acetone solution of 2:6-di-n-octyl-4-aminophenol with aqueous sodium dichromate. 2:6 - Di - n - octyl - 4 - aminophenol is prepared by reducing the nitro compound using Raney nickel catalyst. 2:6 - Di - n - octyl - 4 - nitrophenol is prepared by refluxing a mixture of 10-nonadecanone, sodium nitromalonaldehyde and potassium hydroxide in aqueous ethyl alcohol. Specifications 2562/13, [Class 98 (ii)], 431,487, 524,154, 524,554, 524,555, 541,589, 545,448, 557,750, 557,802, [all in Group XX], 562,205, 680,488 and 739,913 are referred to.