1,4-Dioxane brief introduction

1,4-二噁烷（常简称为二噁烷），透明无色的单环杂环有机化合物，在室温下为液体，有轻微类似乙醚的清香气味，是常用的非质子溶剂。分子式为 C4H8O2，沸点为 101 °C，可与水和常见有机溶剂混溶，有潮解性。 二恶烷的极性比乙醚强，熔点也比乙醚高。溶解能力较强，强于四氢呋喃，与二甲基甲酰胺相近。无水时容易生成爆炸性的过氧化物，蒸馏会使过氧化物的浓度增大，造成危险。

1,4-Dioxane Basic information

1,4-Dioxane Numbering system

1,4-Dioxane Physical and Chemical Properties

• Appearance and characteristics:

• Colorless Transparent Liquid 

• Density:

• 1.500 g/mL at 25 °C

• Boiling point:

• 101 °C

• Melting point:

• 12 °C

• Flash point:

• 54 °F

• Refractive index:

• n20/D 1.422(lit.)

• Water solubility:

• SOLUBLE

• Stability:

• Stable. Incompatible with oxidizing agents, oxygen, halogens, reducing agents, moisture. Highly flammable - note wide explosive range. May form explosive peroxides in storage (rate of formation increased by heating, evaporation or exposure to light).

• Storage conditions:

• The warehouse is ventilated, low-temperature and dry, and stored separately from oxidants and acids

• Steam density:

• 3 (vs air)

• Steam pressure:

• 11.2mmHg at 25°C

security information

• RTECS：

• JG8225000

• Safety instructions:

• S9-S16-S36/37-S46-S45-S53-S7-S62-S26-S24/25-S23

• WGK Germany：

• 3

• Hazard category code:

• R11; R19; R36/37; R40; R66

• Dangerous goods transportation code:

• UN 1993 3/PG 2

• Customs code:

• 2942000000

• Hazard category:

• 3

• Packaging grade:

• II

• Dangerous goods signs:

• F

• Hazard description:

• H225; H319; H335; H351

• Danger signs:

• GHS02, GHS07, GHS08

• Signal words:

• Danger

• Supplementary Hazard Statement:

• May generate explosive peroxides, repeated exposure may cause skin dryness or cracking.

• Hazard prevention instructions:

• P210; P261; P281; P305 + P351 + P338

Production method and purpose

Production method

Refining method: The main impurities include acetaldehyde, 2-methyl-1,3-dipentane, acetals, peroxides, and moisture. When the impurity content is not high, metal sodium can be added and refluxed for 6-12 hours before direct distillation. When containing a large amount of formaldehyde, hydrolysis is required to remove it. Add 27mL of concentrated hydrochloric acid and 200mL of water to 2L of dioxane and reflux for 12 hours. During the reflux process, nitrogen gas is slowly introduced to remove the generated acetaldehyde; After cooling, add solid potassium hydroxide until it no longer dissolves. Separate the water layer and add potassium hydroxide to dry for 24 hours. Reflux the preliminarily dried dioxane with metallic sodium for 6-12 hours, and then distill it in the presence of metallic sodium. The removal of peroxides is the same as that of ether. Add crushed sodium hydroxide to industrial grade dioxane to remove acidic substances and moisture. After filtering out the solid substance, distillation is carried out to obtain pure dioxane.

1. Ethylene glycol is obtained by dehydration catalyzed by sulfuric acid, and its reaction formula is as follows:

2. Ethylene oxide is directly obtained by dimerization, and its reaction formula is as follows: the above dimerization reaction is carried out in the presence of an acidic catalyst, which can be sodium bisulfate, sulfuric acid, boron trifluoride, etc. When industrial grade dioxane needs to be refined into pure product, powdered sodium hydroxide can be added to dioxane to remove acidic substances and moisture, filter out solid substances, and distill to obtain the finished product.

3. The main reaction for the intramolecular dehydration of diethylene glycol to produce dioxane under the action of protonic acid is as follows:

use to

Mainly used as an extractant in the pharmaceutical industry and as a stabilizer in printing ink. And it can be used as a metal surface treatment agent, as well as in cosmetics, fragrance manufacturing, electroplating, and other fields.