Background[1][2]
Diethylene Glycol Diethyl Ether, also known as 2-ethoxyethyl ether, contains multiple ether bonds in the molecule and is mostly used in organic solvents, resins, paints, cleaning agents, dyes, and auxiliaries. Colorants, etc. Because it is miscible with most alcohols, ketones, ethers, halogenated hydrocarbons, etc., and has good solubility for alkali metal hydroxides, it plays an irreplaceable role in organic synthesis.
Structure
Preparation[3][4][5][6]
Synthetic route of diethylene glycol diethyl ether
In this experiment, diethylene glycol monoethyl ether was first reacted with sodium hydroxide to produce sodium diethylene glycol ether. The resulting sodium diethylene glycol ether was then used as a phase transfer catalyst with tetrabutylammonium bromide [5, 6], and then perform a synthesis reaction under the action of ethyl chloride to generate diethylene glycol diethyl ether.
The reaction formula is as follows:
CH3CH2OCH2CH2OCH2CH2OH+NaOH→CH3CH2OCH2CH2OCH2CH2ONa + H2O
CH3CH2OCH2CH2OCH2CH2ONa+CH3CHCl→NaCl+CH3CH2OCH2CH 2OCH2CH2OCH2CH3
Experimental method:
Add 100g of diethylene glycol monoethyl ether into a four-necked flask equipped with a thermometer, reflux condenser and stirrer, turn on the stirrer, add a certain molar ratio of alkali under stirring, and then add a certain ratio of tetrabutyl Ammonium bromide (C16H36BrN). After preheating the ethyl chloride, pass the ethyl chloride through, raise the temperature to the reaction temperature (115°C), and perform an etherification reaction for 3.0 hours. After the reaction is completed, add a certain amount of water to wash and cool down. After the temperature drops to normal temperature, take the upper clear liquid and detect it by gas chromatography. Calculate the conversion rate of diethylene glycol monoethyl ether based on the chromatography results.
Calculation of reaction conversion rate
The obtained samples were analyzed by gas chromatography, the various peaks that appeared were identified by internal standards, and the corresponding substances at each moment were analyzed. From the chromatogram, the expression of conversion rate is:
Conversion rate = peak area of diethylene glycol diethyl ether/(peak area of diethylene glycol diethyl ether + peak area of diethylene glycol monoethyl ether) × 100%
The catalytic synthesis of diethylene glycol diethyl ether using diethylene glycol monoethyl ether and sodium hydroxide as raw materials was studied. The effects of the type of base, the molar ratio of diethylene glycol monoethyl ether to the base, the reaction temperature, and the amount of catalyst on the reaction conversion rate were investigated. Experimental results show that the optimal synthesis conditions for diethylene glycol diethyl ether are: n (monoethyl ether): n (NaOH) = 1:1.5, the amount of catalyst is 5% of diethylene glycol monoethyl ether, and the temperature is 115°C. The conversion rate is 95.8571%. Compared with the traditional process, this process has mild reaction conditions, simple operation, short reaction time, and high conversion rate. It is an efficient and environmentally friendly synthesis process.
Impact on the environment[7]
Health hazards
Routes of invasion: inhalation, ingestion, percutaneous absorption.
Health Hazards: May be harmful if inhaled, ingested or absorbed through skin. Irritating to eyes and may be irritating to skin.
Toxicological information and environmental behavior
Toxicity: low toxicity.
Acute toxicity: LD504390mg/kg (orally in rats); 2440mg/kg (orally in guinea pigs)
Hazardous characteristics: There is a risk of combustion and explosion when exposed to open flame, high heat or contact with oxidants. Potentially explosive peroxides may be formed on contact with air or exposure to light. If exposed to high heat, the internal pressure of the container will increase and there is a risk of cracking and explosion.
Combustion (decomposition) products: carbon monoxide, carbon dioxide.
Emergency treatment methods
1. Emergency response to leakage
Evacuate personnel in the leaked contaminated area to a safe area, prohibit irrelevant personnel from entering the contaminated area, and cut off the source of fire. It is recommended that emergency responders wear gas masks and general fire protective clothing. Plug the leak while ensuring safety. Water mist reduces evaporation but does not reduce the flammability of a spill in a confined space. Mix with sand or other non-flammable adsorbent.Collect, then collect and transport to waste disposal sites for disposal. You can also use emulsion made of non-flammable dispersant for scrubbing, and put the diluted wash water into the wastewater system. If there is a large amount of leakage, use dikes to contain it, then collect, transfer, recycle or dispose of it after harmless treatment.
2. Protective measures
Respiratory protection: Wear a gas mask when you may be exposed to its vapor. In high concentration environments, wear self-contained breathing apparatus.
Eye protection: Generally no special protection is required. Chemical safety glasses can be worn when exposed to high concentrations.
Body protection: Wear appropriate work clothes.
Hand protection: Wear protective gloves.
Others: Smoking, eating and drinking are strictly prohibited at the work site. After work, shower and change clothes. Pay attention to personal hygiene.
3. First aid measures
Skin contact: Take off contaminated clothing and rinse with running water.
Eye contact: Lift eyelids immediately and rinse with running water.
Inhalation: Leave the scene quickly to fresh air. Provide artificial respiration if necessary. Seek medical attention.
Ingestion: If swallowed by mistake, drink plenty of warm water, induce vomiting, and seek medical attention.
Fire extinguishing methods: foam, dry powder, carbon dioxide, sand, 1211 fire extinguishing agent.
References
[1] Xu Qi, Cai Zhaosheng, Yang Chunsheng, et al. Synthesis of diethylene glycol methyl ethyl ether [J]. Fine Petrochemicals, 2005, (01): 28-30.
[2] Cai Zhaosheng. Synthesis and Application of Diethylene Glycol Methylhexyl Ether[J]. Chemical Technology Market, 2005 (08): 1-4.
[3] Yang Chunsheng, Cai Zhaosheng, Xu Qi, et al. Synthesis of diethylene glycol methyl ethyl ether and optimization of its synthesis conditions [J]. Chemistry World, 2006, 47(05): 287-289.
[4]Xu Zhaohui, Liao Weilin, Liu Deyong. Research on the synthesis of diglyme by Williamson reaction [J]. Chemistry World, 2006(7):417-419.
[5] Rui Peixin, Zhou Peng, Liao Weilin, et al. Synthesis of diethylene glycol dimethyl ether by Williamson reaction and optimization of its synthesis conditions [J]. Jiangxi Chemical Industry, 2009 (1): 54-56.
[6] Shi Zhuo, Liu Chang, Zheng Biqiang, et al. Phase transfer catalysis in organic synthesis [J]. Pharmaceutical and Chemical Engineering, 2017, 43 (09): 182.
[7] Ethylene glycol diethyl ether. China Chemical Manufacturing Network.
