Ethylene glycol is prepared from a carbohydrate source in a process, wherein hydrogen, the carbohydrate source, a liquid diluent and a catalyst system are introduced as reactants into a reaction zone; wherein the catalyst system comprises a tungsten compound and ruthenium as hydrogenolysis metal and further at least one promoter metal, selected from transition and post-transition metals; wherein the carbohydrate source is reacted with hydrogen in the presence of the catalyst system to yield a product mixture comprising ethylene glycol and butylene glycol. Butylene glycol may selectively be removed from the product mixture by azeotropic distillation using an entraining agent.

Ethylene glycol is prepared from a carbohydrate source in a process, wherein hydrogen, the carbohydrate source, a liquid diluent and a catalyst system are introduced as reactants into a reaction zone; wherein the catalyst system comprises a tungsten compound and ruthenium as hydrogenolysis metal and further at least one promoter metal, selected from transition and post-transition metals; wherein the carbohydrate source is reacted with hydrogen in the presence of the catalyst system to yield a product mixture comprising ethylene glycol and butylene glycol. Butylene glycol may selectively be removed from the product mixture by azeotropic distillation using an entraining agent.

The invention provides a process for the separation of MEG and 1,2-BDO from a first mixture comprising MEG and 1,2-BDO in a weight ratio of at least 10:1 (MEG:1,2-BDO), said process comprising the steps of; (i) providing the first mixture as a feed to a distillation column at a point in the range of from 20 to 80% of the column height; (ii) operating the distillation at a temperature in the range of from 120 to 190 C. and at a pressure in the range of from 5 kPa to atmospheric pressure; (iii) removing an MEG stream from the distillation column at a point below the point at which the first mixture is fed; (iv) removing an overheads stream comprising an azeotrope of MEG and 1,2-BDO.

The invention provides a process for the separation of MEG and 1,2-BDO from a first mixture comprising MEG and 1,2-BDO in a weight ratio of at least 10:1 (MEG:1,2-BDO), said process comprising the steps of; (i) providing the first mixture as a feed to a distillation column at a point in the range of from 20 to 80% of the column height; (ii) operating the distillation at a temperature in the range of from 120 to 190 C. and at a pressure in the range of from 5 kPa to atmospheric pressure; (iii) removing an MEG stream from the distillation column at a point below the point at which the first mixture is fed; (iv) removing an overheads stream comprising an azeotrope of MEG and 1,2-BDO.

The invention provides a process for separating monoethylene glycol from a mixture comprising monoethylene glycol and 1,2-butanediol, said process comprising the steps of: a. providing a first stream comprising monoethylene glycol and 1,2-butanediol to a first distillation zone operated at a first pressure and under conditions to remove a first bottoms stream comprising 1,2-butanediol and to remove a first azeotrope of monoethylene glycol and 1,2-butanediol from the first distillation zone as a first overheads stream; b. withdrawing said first overheads stream from said first distillation zone; and c. providing said first overheads stream to a second distillation zone operated at a second pressure higher than said first pressure and under conditions to remove a second bottoms stream comprising monoethylene glycol and providing a second azeotrope of monoethylene glycol and 1,2-butanediol as a second overheads stream; d. withdrawing said second overheads stream from the second distillation zone and providing it to the first distillation zone as at least a portion of the first stream comprising monoethylene glycol and 1,2-butanediol, e. wherein the mixture comprising monoethylene glycol and 1,2-butanediol is initially provided to at least one of the first distillation zone and the second distillation zone.

The invention provides a process for separating monoethylene glycol from a mixture comprising monoethylene glycol and 1,2-butanediol, said process comprising the steps of: a. providing a first stream comprising monoethylene glycol and 1,2-butanediol to a first distillation zone operated at a first pressure and under conditions to remove a first bottoms stream comprising 1,2-butanediol and to remove a first azeotrope of monoethylene glycol and 1,2-butanediol from the first distillation zone as a first overheads stream; b. withdrawing said first overheads stream from said first distillation zone; and c. providing said first overheads stream to a second distillation zone operated at a second pressure higher than said first pressure and under conditions to remove a second bottoms stream comprising monoethylene glycol and providing a second azeotrope of monoethylene glycol and 1,2-butanediol as a second overheads stream; d. withdrawing said second overheads stream from the second distillation zone and providing it to the first distillation zone as at least a portion of the first stream comprising monoethylene glycol and 1,2-butanediol, e. wherein the mixture comprising monoethylene glycol and 1,2-butanediol is initially provided to at least one of the first distillation zone and the second distillation zone.

The invention provides a process for separating monoethylene glycol from a mixture comprising monoethylene glycol and 1,2-butanediol, said process comprising the steps of: a. providing a first stream comprising monoethylene glycol and 1,2-butanediol to a first distillation zone operated at a first pressure and under conditions to remove a first bottoms stream comprising 1,2-butanediol and to remove a first azeotrope of monoethylene glycol and 1,2-butanediol from the first distillation zone as a first overheads stream; b. withdrawing said first overheads stream from said first distillation zone; and c. providing said first overheads stream to a second distillation zone operated at a second pressure higher than said first pressure and under conditions to remove a second bottoms stream comprising monoethylene glycol and providing a second azeotrope of monoethylene glycol and 1,2-butanediol as a second overheads stream; d. withdrawing said second overheads stream from the second distillation zone and providing it to the first distillation zone as at least a portion of the first stream comprising monoethylene glycol and 1,2-butanediol, e. wherein the mixture comprising monoethylene glycol and 1,2-butanediol is initially provided to at least one of the first distillation zone and the second distillation zone.

A methanol/MMA azeotrope is broken or avoided by a method comprising the steps of (1) raising the pressure within a first vessel, e.g., a distillation column, that contains a methanol/MMA azeotrope, (2) collecting the azeotrope as a liquid, and then in a second, separate vessel, e.g., another distillation column, (3) raising the pressure sufficiently to allow for the breaking of or avoidance of the azeotrope and the recovery of the methanol.

A methanol/MMA azeotrope is broken or avoided by a method comprising the steps of (1) raising the pressure within a first vessel, e.g., a distillation column, that contains a methanol/MMA azeotrope, (2) collecting the azeotrope as a liquid, and then in a second, separate vessel, e.g., another distillation column, (3) raising the pressure sufficiently to allow for the breaking of or avoidance of the azeotrope and the recovery of the methanol.

The invention provides a process for the separation of a diol from a product stream. The process includes the steps of: i) separating the product stream comprising three or more C2 to C6 diols, C3 to C6 sugar alcohols, and C4 to C6 polyhydric alcohols with at least 3 hydroxyl groups in the molecule, and a catalyst, to produce a first stream comprising the three or more C2 to C6 diols; ii) separating the first stream comprising the three or more C2 to C6 diols into a) a second stream comprising a first diol and unsaturated hydrocarbons and/or one or more compounds with a carbonyl group and b) a third stream comprising two or more diols; iii) hydrogenating the second stream comprising a first diol and unsaturated hydrocarbons and/or one or more compounds with a carbonyl group to provide a purified diol stream.