Texaco Chemical Company

Texaco Inc.

Robert A Meyer

Edward T Marquis

John R Sanderson

William A Smith

Kenneth P Keating

Eileen T Nguyen

Howard F Payton

Terry L Renken

Mark A Mueller

Robert M Steinberg

David L Miller

Gregory B Demoll

A process for recovery of molybdenum from residual fractions derived from an epoxidation reaction of propylene with tertiary butyl hydroperoxide in liquid phase with tertiary butyl alcohol, in the presence of soluble molybdenum, which process comprises:

Molybdenum recovery

A process for recovery of molybdenum from residual fractions derived from an epoxidation reaction of propylene with tertiary butyl hydroperoxide in liquid phase with tertiary butyl alcohol, in the presence of soluble molybdenum, which process comprises: Fractionating epoxidation reaction product for obtaining a liquid fraction containing essentially all molybdenum from the reaction product; Contacting the liquid fraction with anhydrous ammonia for forming a precipitate containing the major portion of the molybdenum and a liquid phase containing 500 ppm or less molybdenum; Separating the liquid phase from the precipitated solid; Evaporating the liquid phase under conditions of elevated temperatures and reduced pressure in the presence of 1 to 3% water for separation into an evaporator overhead vapor essentially free of molybdenum and an evaporator concentrate comprising essentially all of the molybdenum fed to the evaporator; Rapidly cooling evaporator concentrate from about evaporation temperature to about room temperature or less for converting the evaporator concentrate into a brittle, fracturable solid which is easier to accumulate and dispose of in an environmentally acceptable manner.

Impure propylene oxide is purified by a distillation process wherein it is (a) extractively distilled in a first column using a C.sub.2 to C.sub.6 alkylene glycol extractive distillation agent to form a first overhead fraction comprising propylene oxide, C.sub.5 -C.sub.7 hydrocarbons methanol, water and oxygen-containing impurities, (b) wherein the first overhead fraction is separated in a second column into a second overhead fraction comprising most of the pentanes, pentenes and oxygen-containing impurities and a partially purified propylene oxide bottoms fraction comprising propylene oxide, hexenes, hexanes, and only residual quantities of pentenes and pentanes, (c) wherein the partially purified bottoms fraction is extracting distilled in a third column using a C.sub.7 -C.sub.10 alkane hydrocarbon extractive distillation agent to provide a further purified bottoms fraction containing substantially all of the propylene oxide, hexenes, hexanes charged to the third distillation column, and (d) the further purified bottoms fraction is extractively distilled in a fourth column using a C.sub.7 to C.sub.10 alkane hydrocarbon extractive distillation agent to provide a purified propylene oxide overhead fraction consisting essentially of propylene oxide.

Plural stage purification of propylene oxide

An organic solution of a soluble molybdenum compound is ammonated with ammonia, ammonium hydroxide and/or an ammonium salt in order to significantly reduce the electrical resistance of the solution and a direct electric current is passed therethrough in order to collect a significant amount of the molybdenum in solid form at the negative electrode. Preferably, an epoxidation reaction product formed by the molybdenum catalyzed reaction of propylene with tertiary butyl hydroperoxide to provide propylene oxide and tertiary butyl alcohol is separated by distillation into a propylene fraction, a propylene oxide fraction, a tertiary butyl alcohol fraction and a heavy liquid distillation fraction containing substantially all of the dissolved molybdenum catalyst, the heavy liquid distillation fraction is saturated with ammonia to precipitate the molybdenum therefrom, the precipitated molybdenum is removed from the ammonated heavy distillation fraction and a direct electric current is passed through the remaining liquid portion of the ammonated fraction in an electrolytic cell in order to collect a significant portion of the remaining molybdenum residually dissolved therein at the cathode.

Separation of molybdenum

In the preparation of tertiary butyl alcohol and a linear C.sub.3 -C.sub.12 mono epoxide by the epoxidation reaction of a linear C.sub.3 -C.sub.12 alpha mono olefin with tertiary butyl hydroperoxide in solution in tertiary butyl alcohol in the presence of a catalytic amount of a soluble complex of molybdenum with ethylene glycol, a portion of the catalyst that is used is a recycle (final) ethylene glycol solution of a complex of ethylene glycol with ammonium-containing molybdenum compounds prepared from ethylene glycol and a precipitate of solid ammonium-containing molybdenum compounds formed by saturating a heavy distillation fraction with ammonia to thereby form a liquid amination product containing a precipitate of solid ammonium-containing molybdenum compounds; the heavy distillation fraction being obtained by distillation of the epoxidation reaction product.

Preparation of mono epoxides and tertiary butyl alcohol using

The distillation product fraction obtained from an isobutane oxidation reaction product after the removal of unreacted isobutane will contain tertiary butyl hydroperoxide, tertiary butyl alcohol and carboxylic acid contaminants such as formic acid, acetic acid and isobutyric acid. It has been discovered that when the distillation product fraction is treated with about 1/2 to 1 equivalents of calcium oxide and/or calcium hydroxide based on the carboxylic acid content of the distillate product fraction, a portion of the carboxylic acid contaminants will precipitate thus partially purifying the distillation product fraction so that, thereafter, molybdenum precipitation will be substantially inhibited when the thus-treated distillation product fraction is used as a feedstock for an epoxidation reaction wherein tertiary butyl hydroperoxide is reacted with an olefin in the presence of a soluble molybdenum catalyst to provide an olefin epoxide and additional tertiary butyl hydroperoxide.

Treatment of tertiary butyl hydroperoxide distillation fraction to

An epoxidation reaction product formed by the molybdenum catalyzed reaction of propylene with tertiary butyl hydroperoxide to provide propylene oxide and tertiary butyl alcohol is separated by distillation into a propylene fraction, a propylene oxide fraction, a tertiary butyl alcohol fraction and a heavy liquid distillation fraction composed primarily of tertiary butyl hydroperoxide, tertiary butyl alcohol, dissolved molybdenum catalyst, and impurities including lower aliphatic C.sub.1 -C.sub.4 carboxylic acids, and the heavy liquid distillation fraction is saturated with hydrogen to precipitate the molybdenum therefrom for recovery.

Precipitation of molybdenum

Purified propylene oxide is recovered from an impure propylene oxide feedstock contaminated with more than 50 ppm of six carbon atom hydrocarbon impurities by a solvent extraction process wherein:

Purification of propylene oxide by liquid extraction

Methyl formate is removed from impure propylene oxide by contacting the impure propylene oxide in a treating zone with a basic ion exchange resin for a period of time sufficient to convert the methyl formate to formic acid and methanol, and by withdrawing a substantially methyl formate-free treated propylene oxide product from the treating zone.

Method for the purification of propylene oxide

An epoxidation reaction product formed by the molybdenum catalyzed reaction of propylene with tertiary butyl hydroperoxide to provide propylene oxide and tertiary butyl alcohol is separated by distillation into a propylene fraction, a propylene oxide fraction, a tertiary butyl alcohol fraction and a heavy liquid distillation fraction composed primarily of tertiary butyl hydroperoxide, tertiary butyl alcohol, dissolved molybdenum catalyst, and impurities including lower aliphatic C.sub.1 -C.sub.4 carboxylic acids, and the heavy liquid distillation fraction is saturated with ammonia to precipitate the molybdenum therefrom for recovery.

Removal of acidic contaminants from tertiary butyl hydroperoxide

An epoxidation reaction product formed by the molybdenum catalyzed reaction of propylene with tertiary butyl hydroperoxide to provide propylene oxide and tertiary butyl alcohol is separated by distillation into a propylene fraction, a propylene oxide fraction, a tertiary butyl alcohol fraction and a heavy liquid distillation fraction composed primarily of tertiary butyl hydroperoxide, tertiary butyl alcohol, dissolved molybdenum catalyst, and impurities including lower aliphatic C.sub.1 -C.sub.4 carboxylic acids, and the dissolved molybdenum content of the heavy distillation fraction is adjusted to about 300 to 500 ppm of dissolved molybdenum, if necessary, by treatment with a precipitating agent and contacted with a solid adsorbent consisting essentially of a synthetic, porous, high surface area amorphous magnesium silicate.

Removal of trace quantities of molybdenum

Tertiary butyl hydroperoxide and tertiary butyl alcohol are recovered from the reaction product formed by reacting excess propylene with tertiary butyl hydroperoxide in solution in tertiary butyl alcohol in the presence of a soluble molybdenum catalyst, by fractionating the reaction produce to provide distillate propylene, propylene oxide, and tertiary butyl alcohol fractions and a heavy distillation fraction comprising tertiary butyl hydroperoxide, tertiary butyl alcohol and impurities, including dissolved molybdenum catalyst, the tertiary butyl hydroperoxide and tertiary butyl alcohol being recovered from the heavy distillation fraction by vacuum evaporation under evaporation conditions including a temperature of about 25.degree. to about 160.degree. C. and a pressure of about 2 to about 200 mm Hg. in order to provide a lighter condensate fraction comprising about 60 to about 95 wt. % of the heavy distillation fraction and containing from about 70 to about 95 wt. % of tertiary butyl alcohol, about 1 to about 20 wt. % of the tertiary butyl hydroperoxide and from about 15 to about 3 wt. % of impurities and also into a clear liquid heavier residue fraction comprising tertiary butyl alcohol, tertiary butyl hydroperoxide and substantially all of the soluble molybdenum catalyst originally contained in the heavy liquid fraction.

Recovery of tertiary butyl hydroperoxide and tertiary butyl alcohol

A heavy distillation fraction comprising tertiary butyl hydroperoxide, tertiary butyl alcohol, impurities and dissolved molybdenum catalyst resulting from the removel of propylene, propylene oxide and tertiary butyl alcohol from an epoxidation reaction product is mixed with about 5 to about 10 wt. %, based on the weight of the heavy liquid distilation fraction, of a lower aliphatic alcohol containing from 1 to 3 carbon atoms to provide a charge mixture, and the charge mixture is:

An impure propylene oxide feedstock contaminated with from about 50 to about 1000 ppm of methanol and from about 0 to about 1 wt. % of acetone is charged to the lower half of an extractive distillation column containing at least about 25 theoretical plates and an extractive distillation agent consisting essentially of a blend of acetone and water (acetone/water blend) containing about 20 to about 30 wt. % of acetone and, correspondingly, about 80 to about 70 wt. % of water is charged to the tower at a point 4 to 7 theoretical stages above the impure propylene oxide feed point; the extractive distillation agent being introduced into the extractive distillation column in the ratio of said feedstock to said extractive distillation agent of from about 5:1 to about 20:1, whereby an overhead distillate fraction is obtained consisting essentially of propylene oxide contaminated with not more than about 60 ppm of methanol, not more than about 0.02 wt. % of acetone and not more than about 0.3 wt. % of water.

Growing community of inventors

Ballwin, MO, United States of America

Robert A Meyer