Separation and recovery of polychlorinated phenols

Claim 1

A method for the separation and recovery of polychlorinated phenols from dark color-forming impurities contained therein comprising the steps of: (a) introducing into a distilland mixture of at least one polychlorinated phenol and dark color-forming impurities, an amount effective to inhibit color formation of at least one color inhibitor selected from the group consisting of; a phenol derivative selected from the group consisting of 2,6-ditertiary butyl cresol, alpha naphthol, p-aminophenol 4-(methylthio) phenol, 2,2'-methylenebis (4-methyl-6-tertbutyl phenol), 2,2'-methylenebis (4-ethyl-6-tertbutyl phenol), and p-tertiary butyl catechol a hydroquinone compound selected from the group consisting of hydroquinone, 2,5-ditertiary butyl hydroquinone, monotertiary butyl hydroquinone, and the monomethyl ether of hydroquinone; an organic sulfur compound selected from the group consisting of alkyl phenol disulfide, liquid thiocarbamate, ditridecylthiodipropionate, and distearylthiodipropionate; and an organic phosphite compound selected from the group consisting of trinonyl phosphite, tris-2(chloroethyl)-phosphite, and triisooctyl phosphite, (b) distilling the resulting color inhibitor containing distilland to separate polychlorinated phenol vapors therefrom; and (c) condensing said vapor to recover purified polychlorinated phenols in an amount of at least about 84 percent of the impurity-containing polychlorinated phenol.

Claim 2

A method for the separation and recovery of polychlorinated phenols from dark color-forming impurities contained therein comprising the steps of: (a) introducing into a distilland mixture of at least one polychlorinated phenol and dark color-forming impurities, an amount effective to inhibit color formation of at least one color inhibitor selected from the group consisting of; a phenol derivative selected from the group consisting of 2,6-ditertiary butyl cresol, alpha naphthol, p-aminophenol 4-(methylthio) phenol, 2,2'-methylenebis (4-methyl-6-tertbutyl phenol), 2,2'-methylenebis (4-ethyl-6-tertbutyl phenol), and p-tertiary butyl catechol a hydroquinone compound selected from the group consisting of hydroquinone, 2,5-ditertiary butyl hydroquinone, monotertiary butyl hydroquinone, and the monomethyl ether of hydroquinone; an organic sulfur compound selected from the group consisting of alkyl phenol disulfide, liquid thiocarbamate, ditridecylthiodipropionate, and distearylthiodipropionate; and an organic phosphite compound selected from the group consisting of trinonyl phosphite, tris-2(chloroethyl)-phosphite, and triisooctyl phosphite, (b) distilling the resulting color inhibitor containing distilland to separate polychlorinated phenol vapors therefrom; and (c) condensing said vapor to recover purified polychlorinated phenols in an amount of at least about 84 percent of the impurity-containing polychlorinated phenol.

Claim 6

A method for the separation and recovery of pentachlorophenol from dark color-forming impurities contained therein comprising the steps of: (a) introducing into a distilland mixture of pentachlorophenol and dark color-forming impurities, an amount effective to inhibit color formation of at least one color inhibitor selected from the group consisting of a phenol derivative selected from the group consisting of 2,6-ditertiary butyl cresol, alpha naphthol, p-aminophenol, 4-(methylthio) phenol, 2,2'-methylenebis (4-methyl-6-tertbutyl phenol), 2,2'-methylenebis (4-ethyl-6-tertbutyl phenol), and p-tertiary butyl catechol; a hydroquinone compound selected from the group consisting of hydroquinone 2,5-ditertiary butyl hydroquinone, monotertiary butyl hydroquinone, and the monomethyl ether of hydroquinone; an organic sulfur compound selected from the group consisting of alkyl phenol disulfide, liquid thiocarbamate, ditricedylthiodipropionate, and distearylthiodipropionate; and an organic phosphite compound selected from the group consisting of trinonyl phosphite, tris-2(chloroethyl)-phosphite, and triisooctyl phosphite; (b) distilling the resulting color inhibitor containing distilland at a pressure of above about 30 mm. Hg and a temperature above about 185° C to separate pentachlorophenol vapors therefrom; and (c) condensing said vapor to recover purified pentachlorophenol in an amount of at least about 84 percent of the impurity-containing penthachlorpheol.

Claim 7

A method for the separation and recovery of pentachlorophenol from dark color-forming impurities contained therein comprising the steps of: (a) introducing into a distilland mixture of pentachlorophenol and dark color-forming impurities, an amount effective to inhibit color formation of at least one color inhibitor selected from the group consisting of a phenol derivative selected from the group consisting of 2,6-ditertiary butyl cresol, alpha naphthol, p-aminophenol, 4-(methylthio) phenol, 2,2'-methylenebis (4-methyl-6-tertbutyl phenol), 2,2'-methylenebis (4-ethyl-6-tertbutyl phenol), and p-tertiary butyl catechol; a hydroquinone compound selected from the group consisting of hydroquinone 2,5-ditertiary butyl hydroquinone, monotertiary butyl hydroquinone, and the monomethyl ether of hydroquinone; an organic sulfur compound selected from the group consisting of alkyl phenol disulfide, liquid thiocarbamate, ditricedylthiodipropionate, and distearylthiodipropionate; and an organic phosphite compound selected from the group consisting of trinonyl phosphite, tris-2(chloroethyl)-phosphite, and triisooctyl phosphite; (b) distilling the resulting color inhibitor containing distilland at a pressure of above about 30 mm. Hg and a temperature above about 185° C to separate pentachlorophenol vapors therefrom; and (c) condensing said vapor to recover purified pentachlorophenol in an amount of at least about 84 percent of the impurity-containing penthachlorpheol.