A process for removing water from an oxidative esterification reactor includes (a) conducting an oxidative esterification reaction in a reactor; (b) removing a crude product stream from the reactor; (c) passing a first portion of the crude product stream directly to a product recovery zone; (d) introducing a second portion of the crude product stream to a distillation column to generate a column overheads stream and a column bottoms stream; (e) passing at least a portion of the columns bottoms stream to the product recovery zone; and (f) recycling a recycle stream comprising at least a portion of the overheads stream to the reactor; wherein the recycle stream contains less than 1 weight percent (wt %) water based on the total weight of the recycle stream, wherein the weight ratio of the first portion to the second portion is at least 1:10, and wherein the amount of the recycle stream recycled to the reactor is such that the reactor contains less than or equal to 2.5 wt % water, based on the weight of the reactor contents.

A process for removing acetaldehyde from a mixture of methyl acetate, dimethyl ether and acetaldehyde comprising distilling mixtures derived from carbonylating dimethyl ether in the presence of a zeolite catalyst to generate an overhead stream depleted in acetaldehyde as compared to the feed mixture, a base stream depleted in acetaldehyde as compared to the feed mixture and a sidedraw stream enriched in acetaldehyde as compared to the feed mixture and withdrawing from the column the sidedraw stream enriched in acetaldehyde at a point above the feed point of the feed mixture to the column. Purified mixtures may be utilized as feedstock to processes for the co-production of acetic acid and dimethyl ether.

Catalytic dehydration-hydrolysis process for the co-production of acetic acid and dimethyl ether from a mixture of methanol and methyl acetate and water in which the amount of water fed to the process is controlled by the steps of dehydrating a methanol feed to provide a crude product containing dimethyl ether, unconverted methanol and water, recovering therefrom a stream containing dimethyl ether, water and methanol and a water stream and separating dimethyl ether from the dimethyl-ether containing stream to produce a methanol stream containing methanol and water. At least part of the methanol stream and methyl acetate is supplied to the dehydration-hydrolysis process.

A process for producing acetic acid is disclosed in which the water concentration is controlled in the side stream between two columns. Controlling the water concentration by the liquid light phase recycle controls the hydrogen iodide concentration in the side stream to be less than 50 wppm.

A catalytic dehydration-hydrolysis process for the co-production of acetic acid and dimethyl ether from a mixture of methanol and methyl acetate and water in which the amount of water fed to the process is controlled by the steps of dehydrating a methanol feed to provide a crude product comprising dimethyl ether, unconverted methanol and water; recovering therefrom a stream comprising dimethyl ether, water and methanol and a water stream; separating dimethyl ether from the dimethyl-ether containing stream to produce a methanol stream comprising methanol and water; and supplying to the dehydration-hydrolysis process at least part of the methanol stream and methyl acetate.

A process for removing acetaldehyde from a mixture of methyl acetate, dimethyl ether and acetaldehyde comprising distilling mixtures derived from carbonylating dimethyl ether in the presence of a zeolite catalyst to generate an overhead stream depleted in acetaldehyde as compared to the feed mixture, a base stream depleted in acetaldehyde as compared to the feed mixture and a sidedraw stream enriched in acetaldehyde as compared to the feed mixture and withdrawing from the column the sidedraw stream enriched in acetaldehyde at a point above the feed point of the feed mixture to the column. Purified mixtures may be utilised as feedstock to processes for the co-production of acetic acid and dimethyl ether.

A process for producing acetic acid is disclosed in which the water concentration is controlled in the side stream between two columns. Controlling the water concentration by the liquid light phase recycle controls the hydrogen iodide concentration in the side stream to be less than 50 wppm.

A method for producing a tin compound represented by formula (A1) with a purity of 95 mol % or higher, involves a step of distilling the tin compound, in which the number of plates of the distillation is 10 or more, and the reflux ratio is 30 or less.

RSnX.sub.3(A1)

In formula (A1), R is an organic group with 1 to 30 carbon atoms, and may be substituted with halogen, oxygen atoms, or nitrogen atoms. X is selected from OR and NR.sub.2. R is an organic group with 1 to 10 carbon atoms, and part may be substituted with halogen, oxygen atoms, or nitrogen atoms. When there are multiple R groups in the molecule, they may have the same or different structures, and they may be bonded to each other to form a cyclic structure.

Provided is a method for preparing synthesis gas, and more particularly, a method for preparing synthesis gas including: supplying a pyrolysis fuel oil (PFO) stream including a PFO and a pyrolysis gas oil (PGO) stream including a PGO discharged from a naphtha cracking center (NCC) process to a distillation tower as a feed stream (S10); and supplying a lower discharge stream from the distillation tower to a combustion chamber for a gasification process to obtain synthesis gas (S20), wherein the PGO stream is supplied to an upper end of the distillation tower and the PFO stream is supplied to a lower end of the distillation tower.

Provided is a method capable of yielding high-purity 1,3-butylene glycol having a very low content of a low boiling point component and a high initial boiling point, with a high recovery ratio. A reaction crude liquid containing 1,3-butylene glycol is subjected to product distillation to yield purified 1,3-butylene glycol, through dehydration including removing water by distillation and performing high boiling point component removal including removing a high boiling point component by distillation. A method for producing 1,3 butylene glycol, the method including: distilling a charged liquid having a water content of 1.2 wt. % or less in a product column for use in the product distillation under a condition of a reflux ratio of greater than 0.1; distilling off a liquid in which a low boiling point component is concentrated from above a charging plate; and extracting 1,3-butylene glycol from below the charging plate.