Abstract: 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.

Abstract: 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.

Abstract: Provided is a method capable of yielding high-purity 1,3-butylene glycol having a very low content of a high boiling point component and a low dry point, with a high recovery ratio. A method for producing 1,3-butylene glycol to yield purified 1,3-butylene glycol from a reaction crude liquid containing 1,3-butylene glycol, in which, in a high boiling point component removal column for use in the removing a high boiling point component, a charged liquid containing 1,3 -butylene glycol is distilled under conditions that (i) a reflux ratio is greater than 0.02 in a case where a concentration of 1,3-butylene glycol in the charged liquid is 95% or less, or a reflux ratio is greater than 0.01 in a case where the concentration of 1,3-butylene glycol in the charged liquid is greater than 95%, and (ii) a bottom ratio of less than 30 wt.

Abstract: 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.

Abstract: An indicating instrument which is capable of supplying stable power to an light source is provided.