Provided is a method capable of manufacturing high-purity 1,3-butylene glycol having a high potassium permanganate test value, a very low content of low boiling point components, and a high initial boiling point with a high recovery rate.

A method for manufa.cturing 1,3-butylene glycol is a method for obtaining purified 1,3-butylene glycol from a crude reaction liquid containing 1,3-butylene glycol. In a dehydration column used in the dehydration step, a liquid feed containing 1,3-butylene glycol and water with an acetaldehyde content of 1000 ppm or lower and a crotonaldehyde content of 400 ppm or lower is distilled, and a liquid concentrated with a low boiling point component containing water is distilled off from above a feed plate; and in a product column used in the product distillation step, a 1,3-butylene glycol liquid feed having an acetaldehyde content of 500 ppm or lower and a crotonaldehyde content of 200 ppm or lower is distilled under a condition of a reflux ratio of higher than 0.1.

The present invention relates to a plant for removing C.sub.6-C.sub.11 hydrocarbons from methanol, comprising at least one reactor for the conversion of carbon monoxide and hydrogen to a crude methanol containing hydrocarbons, a distillation column with a head and a sump for the purification of the methanol, and at least one conduit for guiding the crude methanol from the at least one reactor into the distillation column. At its head, the distillation column includes a feed conduit for feeding in water.

The present invention provides a method for operating a rectification column (1000) for separating a mixture (S) containing a component A and a component B having a boiling point higher than that of the component A at an operating pressure of the rectification column (1000) which is lower than ambient pressure, wherein the method comprises a step for controlling the mass fraction of the component B in the product stream of the component A (P1) to a value within a first target range from 0.1% to 5.0% and the mass fraction of the component A in the product stream of the component B (P2) to a value within a second target range from 0.1% to 5.0%, wherein the control is carried out as a function of a controlling temperature (TC) for which a setpoint TC.sub.setpoint is calculated according to the equation TC.sub.setpoint=T2+F.Math.(T1−T2), where F is a factor which is in the range from 0.1 to 0.9 and T1 and T2 are reference temperatures, wherein in the case of a deviation in the measured control temperature (TC) from its setpoint TC.sub.setpoint being found the control temperature (TC) is readjusted to the setpoint TC.sub.setpoint by varying one or more of the following actuating variables: (i) heating of the column bottom (130) by the evaporator (200), (ii) the mass flow {dot over (m)}.sub.A42 of the reflux (A42) fed back into the rectification column, (iii) the mass flow {dot over (m)}.sub.P2 of the product stream P2 and (iv) the mass flow {dot over (m)}.sub.P1 of the product stream P1.

Provided is a method capable of manufacturing high-purity 1,3-butylene glycol having a high potassium permanganate test value, a very low content of low boiling point components, and a high initial boiling point with a high recovery rate.

The method for manufacturing 1,3-butylene is a method for obtaining purified 1,3-butylene glycol from a crude reaction liquid containing 1,3-butylene glycol. In a dehydration column used in a dehydration step, a liquid feed containing 1,3-butylene glycol and water with an acetaldehyde content of 1000 ppm or lower and a crotonaldehyde content of 400 ppm or lower is distilled under a condition of a reflux ratio of higher than 0.3, and a liquid concentrated with a low boiling point component containing water is distilled off from above a feed tray. In a product column used in a product distillation step, a 1,3-butylene glycol liquid feed with an acetaldehyde content of 500 ppm or lower and a crotonaldehyde content of 200 ppm or lower is distilled under a condition of a reflux ratio of higher than 0.1.

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.

A high-purity 1,3-butylene glycol product that is colorless and odorless (or almost colorless and odorless), unlikely to cause coloration and odor over time, and/or unlikely to cause an acid concentration increase over time when the product is left in a state containing water is provided. A 1,3-butylene glycol product containing 1,3-butylene glycol, wherein, after the 1,3-butylene glycol product has been kept at 180° C. for 3 hours in air atmosphere, at least one of contents of compounds represented by the following Formula (A) or (B) is less than 8 ppm. In the following formula, R.sup.1 to R.sup.4 are the same as or different from each other, and each of R.sup.1 to R.sup.4 is a hydrogen atom, an alkyl group which has from 1 to 4 carbon atoms and may be substituted with a hydroxy group, or an alkenyl group which has from 2 to 4 carbon atoms and may be substituted with a hydroxy group.

The invention relates to a process for the continuous production of acrylic acid, in the absence of organic solvent and in the absence of chemical treatment of the aldehydes, and without employing a dividing-wall column, from a gaseous reaction mixture comprising acrylic acid obtained by gas-phase oxidation of a precursor of acrylic acid.

Provided is a method for purifying a waste solvent by removing carbon dioxide contained in a waste solvent derived from supercritical waste liquid generated after supercritical drying by a decompression process, and removing ammonia by a multi-stage distillation process to obtain a solvent of high purity, which can be reused in producing silica aerogel or a silica aerogel blanket.

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.

A process and system for separating butenes and butanes by extractive distillation using a polar solvent is disclosed. The process may include: contacting a hydrocarbon mixture including butanes and butenes with a lean solvent mixture in an extractive distillation column to form an enriched solvent fraction comprising butenes; recovering an overheads fraction comprising butanes and a bottoms fraction from the extractive distillation column; feeding the bottoms fraction to a stripper including a stripping section and a wash section; recovering the lean solvent mixture as a bottoms fraction and a stripper overheads fraction comprising butenes and water from the stripper; condensing the overheads fraction to form a water fraction and a product butenes fraction; feeding water as reflux to a top of the stripper wash section; feeding at least a portion of the condensed water fraction intermediate the top and bottom of the stripper wash section as a second reflux.