Does anyone have information on the physicochemical properties of phosphorous acid (TNPP) and diethylene glycol monobutyl ether (DGBMBE)?

The third edition of the Solvent Manual contains information on the physical and chemical properties of dibutyl ether of diethylene glycol, although the description of its chemical properties is rather brief. Some data can be obtained by checking CAS: 112-34-5

The properties of these substances can be found easily in some manuals. It is recommended to check it out at the library.

Diethylene glycol, also known as diglycol, is alternatively referred to as ethylene glycol ether or diethyl glycol ether. Its molecular structure is HO-CH2-CH2-O-CH2-CH2-OH, with a molecular weight of C4H10O3, equal to 106.12. It appears as a colorless, odorless, transparent, and hygroscopic viscous liquid; it has a sharp sweet taste, is non-corrosive, and has low toxicity. Boiling point: 245°C, melting point: -6.5°C, freezing point: -10.45°C, flash point: 123.9, refractive index: 1.4472, relative density: 1.1184, viscosity: 0.30 poise. It is readily soluble in water, alcohol, acetone, ether, ethylene glycol, and other polar solvents; its chemical properties are similar to those of ethylene glycol. It can primarily be used as a solvent for various applications, as a desiccant for natural gas, as an extractant for aromatic hydrocarbons, as a lubricant and softener for textiles, as well as a finishing agent. It is also used as a solvent for cellulose nitrate, resins, oils, and printing inks. Additionally, it serves as an antifreeze component in brake fluid and compressor lubricants, can be used to formulate cleaning agents, and acts as a dispersing solvent in other household chemicals such as inks. The molecular structure of diethylene glycol contains both ether bonds and hydroxyl groups, which endow it with unique physical and chemical properties. Therefore, using diethylene glycol as a raw material, various chemical products such as ethers, acids, esters, and amines can be manufactured. Its main products include morpholine and its derivatives, 1,4-dioxane (1,4-dioxacyclohexene), diethylene glycol mono(b)ethers, and diethylene glycol esters (saturated and unsaturated). These products are widely used in industries such as petrochemicals, rubber, plastics, textiles, coatings, adhesives, and pharmaceuticals, showing a very broad range of applications. II. Source of diethylene glycol raw material: Diethylene glycol primarily originates as a by-product of the hydration of ethylene oxide (EO) to produce ethylene glycol (EG). In these by-products, diethylene glycol accounts for approximately 8–9%, triethylene glycol accounts for about 1%, with the remainder being polyethylene glycols of higher molecular weight. The amount of these by-products varies depending on the ratio of ethylene oxide to water used in the reaction. In recent years, with the successive completion and commissioning of large-scale ethylene glycol production facilities in China, the country’s ethylene glycol production capacity has now reached 1.04–1.05 million tons per year. As a result, the production of diethylene glycol has increased rapidly, with an estimated output of around 100,000 tons per year. With the 320,000 tons per year ethylene glycol plant at Nanhai Petrochemical set to come online, and the 380,000 tons per year ethylene glycol plant at Shanghai Petrochemical to be completed in the near future, the production of diethylene glycol across the country and in the Shanghai region will increase further. Therefore, developing downstream products of diethylene glycol and ensuring its comprehensive utilization are projects with great economic value and market potential. III. Applications of major downstream products of diethylene glycol: Using diethylene glycol along with corresponding alcohols or halogenated alkanes as raw materials, diethylene glycol mono (di) methyl ethers and diethylene glycol mono (di) butyl ethers can be produced. These compounds are widely used as solvents in inks, paints, resins, coatings, and dyes; they are also employed as solvents in organic synthesis and as antifreeze additives in automotive fuels. The reaction of diethylene glycol with ammonia yields morpholine, which is used in the production of rubber vulcanization aids, textile auxiliaries, pharmaceuticals, pesticides, and other fine chemical products. The reaction of diethylene glycol with methylamine produces N-methylmorpholine, which is used as a foaming agent for polyurethane plastics, a solvent for organic solvents, and as a catalyst in the synthesis of certain pharmaceuticals. Fatty acid diglycol plasticizers can be produced from diglycol and fatty acids. Used as plasticizers for polyvinyl chloride, they possess good processability and cold resistance, and can replace DBS and DOS. When combined with DOP, DBP, etc., they can improve the low-temperature durability of plastic products. The production process for this product is well-established; both Beijing Yanshan Qianjin Chemical Factory and Harbin Power Chemical Factory have installed facilities for producing C7-9 fatty acid diglycol esters and C5-9 fatty acid diglycols, respectively. Diglycidyl dibenzoate can be synthesized from diethylene glycol and benzoic acid; it can serve as a plasticizer for PVC resin in place of DOP, DBP, and DOS, and is used in the production of PVC products, PVC artificial leather, and PVC flooring. 1,4-Dioxane can be synthesized from diethylene glycol under the catalysis of a protonic acid or a strongly acidic ion-exchange resin. This product is an excellent solvent, reaction medium, and extraction solvent. It is used in the extraction of pharmaceuticals and pesticides, in the dewaxing of petroleum products, as well as in the production of textiles, coatings, synthetic resins, etc. It is also used as a stabilizer for the less toxic chlorinated solvent 1,1,1-trichloroethane, and as a substitute for expensive solvents such as dimethylformamide and furan, which have traditionally been used in the production of polyurethane leather. Furthermore, diglycol diallyl carbonate synthesized from diglycol and allyl alcohol can be used as a raw material for producing lenses ； Diglyme dimethacrylate, synthesized from diglycol and methacrylic acid, is widely used as a crosslinking agent in the production of pressure-sensitive adhesives and photopolymerizable coatings ； Diethylene glycol is also used to produce polyester polyols, which serve as raw materials for the manufacture of polyurethane resins ； Diglycol is also used in the production of important products such as unsaturated resins, diglycolamine, and triglycol. IV. Downstream Derivative Products of Diethylene Glycol 1. Morpholine or N-Methylmorpholine Products Morpholine (1,4-oxazacyclohexane) is one of the important cyclic amines used in industry. Thanks to its oxazacyclic structure, morpholine plays a significant role in chemical manufacturing; it serves as an important organic raw material and chemical intermediate with wide applications in various fine chemical products. It can be used as rubber additives in the rubber processing industry, such as vulcanization accelerators like NOBS, vulcanizing agents like DTDM, anti-aging agents like CTOS, and antioxidants ； Used in the textile industry as auxiliaries for fabric finishing, softeners, brighteners, and other dyeing and weaving aids ； In the pharmaceutical industry, it is used to produce various important drugs such as ribavirin, ibuprofen, and cough suppressants. It is also used as a plastic additive, rust inhibitor, surfactant, tank cleaning agent, component in the formulation of corrosion inhibitors, optical polishing agent, brightener, polyurethane foaming agent, water treatment agent, preservative, and more. Additionally, morpholine is also an important organic solvent. According to the China Chemical Industry News, the current consumption pattern of morpholine abroad is as follows: 5% is used in the production of rubber additives, 20% in the production of corrosion inhibitors, 20% in the production of optical polishing agents, and 10% is used in the production of other morpholine derivatives or for export. The current consumption of morpholine in China differs slightly from that abroad: 2,800 tons are used to produce rubber vulcanization aids, accounting for 70%, 600 tons are used in the pharmaceutical industry, accounting for 15%, 400 tons are used in the production of dyes and pesticides, accounting for 10%, and 200 tons are used for other purposes, accounting for 5%. The production of morpholine currently relies mainly on diethylene glycol and ammonia as raw materials. Under the action of a hydrogenation catalyst, both ammonolysis and dehydration reactions take place simultaneously; the crude morpholine obtained is then distilled to yield pure morpholine with a purity of >99.5% (by weight). Depending on the operating pressure, this technology is divided into three synthesis processes: high-pressure liquid-phase method, low-pressure gas-phase contact method, and atmospheric-pressure gas-phase method. Since Air Products and Chemicals of the United States developed the new low-pressure technology in 1980, several companies now possess production facilities capable of manufacturing tens of thousands of tons of morpholine per year. And countries such as Japan are also competing to develop in this area, but the price of morpholine remains high. At the end of the 1980s, in China there were only a few small morpholine production facilities in places such as Shanghai and Shenyang, and they used the old process based on diethanolamine as a raw material and strong acid dehydration, which resulted in high costs and low economic efficiency. It has seen rapid development in recent years; since the 1990s, several domestic research institutions have developed the diethylene glycol-catalyzed aminolysis cyclization method. Among them, ① the Fushun Petrochemical Research Institute conducted a 500 t/a industrial-scale pilot test at Liaoning Qingyuan Chemical Plant, which was successful. ②The Beijing Research Institute of Petrochemical Science conducted research on the catalytic aminolysis and cyclization of diglycol in low-pressure conditions using continuous-flow fixed-bed reactors, and the synthetic catalyst developed by them was put into use at the Pingdu Chemical Complex in Shandong. ③Nanjing Chemical Plant No. 2’s use of atmospheric-pressure catalytic synthesis of morpholine is a first in China. ④Nanjing Jinling Petrochemical Company contracted the 500-ton/year plant at Piaoshui Fertilizer Factory, which was completed and put into operation in 1993. ⑤Liaoyuan Film Film Factory utilizes a 500-ton/year plant for synthesizing morpholine using the diethylene glycol amination method developed by the R&D institute of Jihua Company. To date, 3 units with a capacity of 500 tons per year have been built using this technology; the amount of diglycol consumed per ton of product is less than 1.7 tons. The quality of the product meets advanced domestic standards as well as BASF’s requirements. New production facilities using diethylene glycol as raw material have been successively built and put into operation in Shandong, Jilin, Anhui, Jiangsu and other regions. However, there are many small and medium-sized enterprises; the largest capacity among them is 800 tons per year, while some have a capacity of only 100 tons per year. The production technologies and product quality vary widely. In 2002, China’s total designed production capacity for morpholine reached 8,700 tons per year; however, due to technical issues, three manufacturers were either shut down or operating at reduced capacity. As a result, China’s actual morpholine production in 2002 was only slightly over 5,000 tons, with imports of morpholine exceeding 2,000 tons each year. According to market statistics in China at the end of 2002, for rubber additives such as anti-scorching agents, vulcanizing agents and accelerators, as well as delayed-action accelerators, the demand was 3,500 tons per year or more ； Pharmaceutical synthesis: Synthesis of moroxydine (Virusin), ibuprofen, naproxen, etc., with a demand of 1,500 tons per year or more ； Corrosion inhibitors: Effective corrosion suppressants for metals such as iron, steel, copper, zinc, and lead; demand amounts to 500 tons per year ； Other aspects: Used as a solvent, in the synthesis of surfactants, as a fluorescent brightener, as a textile additive, and in catalytic applications; the demand amounts to 500–800 tons per year ； About 500 tons for petroleum ； For new pesticides, 300–500 tons. In 2002, China’s total demand for morpholine exceeded 7,000 tons. In recent years, with the continuous advancement of science and technology, new uses for morpholine have emerged. For example, new types of pesticides and pharmaceuticals are being continuously developed and produced, while alkylmorpholine is under research and development as a solvent for the fiber industry. N-methylmorpholine is produced in very small quantities in China, with outdated manufacturing processes and high costs. Abroad, it is mainly produced using new synthetic processes that involve diethylene glycol and methylamine under the action of catalysts. It has also been successfully developed in China. N-methylmorpholine is a foaming catalyst for polyurethane plastics; it is also an excellent solvent, emulsifier, and corrosion inhibitor. Additionally, it is an essential morpholine compound for the synthesis of the pharmaceutical agent aminobenzylcyanotoxin, and can be used as a solvent in the \"new process for manufacturing artificial fibers using the solvent method\". N-Methylmorpholine N-oxide (NMMO) is obtained by reacting morpholine with formaldehyde, followed by reaction with hydrogen peroxide; the crude product is then purified through separation and recrystallization. It is an excellent solvent for manufacturing Lyocell fibers (a type of synthetic fiber produced by spinning wood pulp), and it can also be used in the production of cellophane and food packaging films. Difenoconazole is obtained through a three-step reaction using morpholine, catechol, dimethyl sulfate, and other raw materials. Dimethomorph can be used as a fungicide as well as a corrosion inhibitor and scale preventer in steam boilers. In addition, there are also morpholine series products such as N-ampropylmorpholine and N-phenylmorpholine. In the pharmaceutical industry, morpholine is mainly used in the production of traditional drugs; therefore, market demand for it cannot grow very rapidly. It is estimated that the demand for morpholine in 2005 will be around 1,700 tons. Morpholine can be used as a metal corrosion inhibitor; in China, this field is still in its infancy, but it is expected to see good development in the future. In the rubber industry, morpholine is mainly used to synthesize rubber vulcanization accelerators such as NOBS, DS, OTOS, and 26. If the use of the accelerator NOBS was banned in our country before 2005, it would affect the demand for morpholine in the field of rubber additives. Currently, many toxic accelerants have been banned, which has led to varying degrees of surplus of morpholine; as a result, it is not imported from our country. Therefore, it is expected that demand for morpholine in this sector will not experience significant growth. It is estimated that China’s demand for morpholine in 2005 will be 9,000 tons. 2. Diglycol ether products: Diglycol ether products include the monoethers and diethers of diglycol. Among the important varieties is diethylene glycol monomethyl ether, due to its low toxicity and high boiling point. Therefore, it is particularly suitable as a high-boiling-point solvent for printing inks, dyes, synthetic resins, nitrocellulose, ballpoint pen ink, textile printing, coatings, and high-solid paints ； It is also used as a solvent in organic synthesis and as an industrial cleaner ； Due to its good thermal stability, low freezing point, and low viscosity, it can also be used as a component for synthetic brake fluids and hydraulic fluids in hydraulic control systems ； It can also be used as a waterproofing additive for automotive and aircraft fuels. Diethylene glycol dimethyl ether can be used not only as a high-boiling-point solvent, but also as a solvent for anionic substances and as an absorbent for various gases. The synthesis of diglyme from diglycol primarily employs the Williamson ether synthesis method: diglycol is first converted into sodium monohydrate, which is then reacted with chloromethane; alternatively, one of the hydroxyl groups in diglycol can be replaced by a chlorine atom and the resulting compound reacted with sodium methoxide. Diglyme can also be obtained by the dehydration of methanol and diglycol in the presence of a catalyst. 3. Diethylene glycol dibenzoate products: Diethylene glycol ester products include saturated diethylene glycol esters and unsaturated diethylene glycol esters. Its main varieties include saturated esters such as diethylene glycol dipropionate, diethylene glycol dinitrate, and diethylene glycol diacetate, as well as unsaturated esters such as diethylene glycol dibenzoate and diethylene glycol allyl bicarbonate. Diglyme dibenzoate has a low melting temperature, allowing the resin to dissolve rapidly and thus reducing processing time. It has low volatility during mixing, high stability, and good compatibility with resins; more inorganic fillers can be added to the formulation to enhance the tensile strength of the products and reduce costs. The product exhibits excellent resistance to solvents and oil extraction, and can replace DOP and DBP as a plasticizer for polymers such as polyvinyl chloride leather, floor adhesives, polyurethane elastomers, polyvinyl acetate, and phenolic resins. Its performance is superior to phthalate plasticizers, and it is inexpensive. It can also be used as an additive for cellulose acetate, an additive for adhesives, a dyeing aid for cellulose acetate, and a plasticizer for acrylic latex. It can replace DOP, PBP, and DOS as plasticizers for PVC resin, and is used in the production of PVC products, PVC artificial leather, and PVC flooring. Its synthesis methods mainly involve the esterification of diethylene glycol and benzoic acid in the presence of a catalyst, or an ester exchange reaction between diethylene glycol and methyl benzoate. The production equipment for ester products is usually simple, requires low investment, and the equipment has good versatility as well as strong market adaptability. 4. Synthesis of diglycolic acid from diethylene glycol and development of new unsaturated polyester resins. Diglycolic acid is an important raw material in the fine chemical industry, with a wide range of applications. The diglycidyl ester compounds synthesized using diglycolic acid as a starting material are excellent plasticizers for polyvinyl chloride, while the sodium salt of diglycolic acid is an excellent component in detergents. Different grades of unsaturated polyester resins synthesized from diglycolic acid, diglycol, phthalic anhydride, styrene, etc., can be used respectively to manufacture fiberglass products, electrical insulators, adhesive tapes, and putty products, offering excellent performance and utility. Diglycolic acid can also be used as a plant growth promoter, among other things. The production process of diglycolic acid is relatively simple. There are two synthetic routes for producing diglycolic acid from diols: either by using nitric acid at a concentration of 20% as an oxidizing agent in an oxidation reaction, or by using platinum/active carbon as a catalyst along with air or oxygen as the oxidizing agent to oxidize diethylene glycol into diglycolic acid. The aqueous solution is then concentrated and crystallized to yield the diglycolic acid product. There is extensive research abroad on the synthesis and applications of diglycolic acid, and production facilities have been established in the United States and Germany. Domestically, it is still in the development stage; in 1991, Yanshan Petrochemical Company and the School of Chemical Engineering at Dalian University of Technology successfully synthesized diglycolic acid and a series of unsaturated polyester resins, indicating great potential for further development of this project. 5. 1,4-Dioxane: The product 1,4-dioxane (1,4-dioxanone) possesses the general properties of ethers. It is primarily used as an extractant in pharmaceuticals and organic synthesis, as a solvent for removing paint, as a solvent and dispersant for dyes, and as a substitute for substances such as furan in the production of polyurethane synthetic leather. 1,4-Dioxane can be prepared using ethylene oxide, ethylene glycol, diethylene glycol, etc. as raw materials, under the action of a protonic acid catalyst. From an economic efficiency perspective, using diethylene glycol as a raw material is the most suitable option, as it is a by-product of ethylene glycol production and is inexpensive. From the perspective of the operation process, using diethylene glycol as a raw material is simple and safe. 1,4-Dioxane can be synthesized using various types of protonic acid catalysts; before the 1980s, H2SO4 was primarily used as a catalyst in liquid-phase reactions, and this process caused severe equipment corrosion and environmental pollution. In developing this new process, we use water-resistant, high-silica ZSM-5 zeolite molecular sieves as catalysts for gas-solid phase catalytic reactions. The advantages of this process include high catalyst conversion rates, good selectivity, long catalyst lifespan, simplicity of operation, as well as low environmental pollution and minimal generation of waste materials, placing it at the forefront of world-class technologies. Diethylene glycol undergoes intramolecular dehydration cyclization in the presence of a protonic acid to form dioxane. This technology consists of two parts, namely reaction and separation. The reactants and carrier gas undergo a gas-solid phase catalytic reaction at 250–300°C. The reaction products are separated from the gas phase, while the carrier gas is recycled. The dioxane product is separated from water using azeotropic distillation, and it is separated from minor by-products and unreacted materials through vacuum distillation. The catalyst is regenerated by air calcination, allowing it to be reused.