PRODUCTS

TRIETHYLENE GLYCOL (TEG)

Triethylene glycol, TEG, or triglycol is a colorless odorless viscous liquid with molecular formula HOCH2CH2OCH2CH2OCH2CH2OH. It is used as a plasticizer for vinyl polymers. It is also used in air sanitizer products, such as "Oust" or "Clean and Pure". When aerosolized it acts as a disinfectant. Glycols are also used as liquid desiccants for natural gas and in air conditioning systems. It is an additive for hydraulic fluids and brake fluids and is used as a base for "smoke machine" fluid in the entertainment industry.

CAS No. : 112-27-6
EC No. : 203-953-2

Synonyms:
TRIETHYLENE GLYCOL; 112-27-6; Triglycol; 2,2'-(Ethane-1,2-diylbis(oxy))diethanol; trietilen glikol; 2,2'-Ethylenedioxydiethanol; Triethyleneglycol; Trigen; Triethylenglykol; Triglycol; 2,2'-[Ethane-1,2-diylbis(oxy)]di(ethan-1-ol); 2-[2-(2-Hydroxyethoxy)ethoxy]ethanol; TRIETHYLENE GLYCOL; 112-27-6; Triglycol; 2,2'-(Ethane-1,2-diylbis(oxy))diethanol; 2,2'-Ethylenedioxydiethanol; Triethyleneglycol; Trigen; Triethylenglykol; 1,2-Bis(2-hydroxyethoxy)ethane; 2,2'-(Ethylenedioxy)diethanol; 2-[2-(2-Hydroxyethoxy)ethoxy]ethanol; 3,6-Dioxaoctane-1,8-diol; Ethanol, 2,2'-[1,2-ethanediylbis(oxy)]bis-; Di-beta-hydroxyethoxyethane; 2,2'-Ethylenedioxybis(ethanol); 2,2'-Ethylenedioxyethanol; 2,2'-[ethane-1,2-diylbis(oxy)]diethanol; Triethylene glcol; Glycol bis(hydroxyethyl) ether; Caswell No. 888; Ethylene glycol dihydroxydiethyl ether; Trigol; TEG; Triethylenglykol [Czech]; Bis(2-hydroxyethoxyethane); Ethanol, 2,2'-(ethylenedioxy)di-; 2,2'-(1,2-Ethanediylbis(oxy))bisethanol; Ethylene glycol-bis-(2-hydroxyethyl ether); teg; EINECS 203-953-2; EPA Pesticide Chemical Code 083501; 2-[2-(2-HYDROXY-ETHOXY)-ETHOXY]-ETHANOL; BRN 0969357; Di-.beta.-hydroxyethoxyethane; Ethanol, 2,2'-(1,2-ethanediylbis(oxy))bis-; 2-[2-(2-hydroxyethoxy)ethoxy]ethan-1-ol; Triethylene glycol, 99%; 2,2'-(ethane-1,2-diylbis(oxy))bis(ethan-1-ol); CAS-112-27-6; Trigenos; triethylenglycol; CCRIS 8926; triethylene-glycol; Triethyleneglycol,; Tri-ethylene glycol; 3,8-diol; Polyethyleneglycol 300; ACMC-1C4BE; Polyethylene glycol 1500; EC 203-953-2; Polyethylene Glycol 2000; Triethylene glycol, puriss.; Polyethylene glycol 8,000; Polyethylene Glycol 6,000; 3,6-Dioxa-1,8-octanediol; 4-01-00-02400 (Beilstein Handbook Reference); Polyethylene glycol 10,000; Polyethylene glycol 12,000; Polyethylene glycol 20,000; di(2-ethylbutyrate), diacetate; Ethanol,2'-(ethylenedioxy)di-; Triethylene Glycol Reagent Grade; Triethylene Glycol (Industrial Grade); Polyethylene oxide, M.W. 100,000; Polyethylene oxide, M.W. 300,000; 2-[2-(2-Hydroxyethoxy)ethoxy]ethanol #; Polyethylene oxide, M.W. 1,000,000; SC-79003; Polyethylene glycol (PEG), 50% solution; Triethylene glycol, ReagentPlus(R), 99%; Ethanol,2'-[1,2-ethanediylbis(oxy)]bis-; Polyethylene oxide, M.W. >5,000,000; Triethylene glycol, SAJ first grade, >=96.0%; Triethylene glycol, Vetec(TM) reagent grade, 98%; 2,2'-(Ethane-1,2-diylbis(oxy))diethanol 112-27-6; Triethylene glycol, BioUltra, anhydrous, >=99.0% (GC); alpha,omega-Bis-hydroxy poly(ethylene glycol) (PEG-WM 3.000 Dalton); Triethylene glycol, United States Pharmacopeia (USP) Reference Standard; Poly(oxy-1,2-ethanediyl),??-hydro-??-hydroxy- Ethane-1,2-diol, ethoxylated; Poly(oxy-1,2-ethanediyl),??-hydro-??-hydroxy- Ethane-1,2-diol, ethoxylated 1 - 4.5 moles ethoxylated; TEG

Triethylene Glycol

Properties
Chemical formula C6H14O4
Molar mass 150.174 g·mol−1
Appearance Colorless liquid
Density 1.1255 g/mL
Melting point −7 °C (19 °F; 266 K)
Boiling point 285 °C (545 °F; 558 K)

Properties
Triethylene glycol is a member of a homologous series of dihydroxy alcohols. It is a colorless, odorless and stable liquid with high viscosity and a high boiling point. Apart from its use as a raw material in the manufacture and synthesis of other products, Triethylene glycol is known for its hygroscopic quality and its ability to dehumidify fluids. This liquid is miscible with water, and at a pressure of 101.325 kPa has a boiling point of 286.5 °C and a freezing point of -7 °C. It is also soluble in ethanol, acetone, acetic acid, glycerine, pyridine, aldehydes; slightly soluble in diethyl ether; and insoluble in oil, fat and most hydrocarbons.

Preparation
Triethylene glycol is prepared commercially as a co-product of the oxidation of ethylene at high temperature in the presence of silver oxide catalyst, followed by hydration of ethylene oxide to yield mono(one)-, di(two)-, tri(three)- and tetraethylene glycols.

Applications
Triethylene glycol is used by the oil and gas industry to "dehydrate" natural gas. It may also be used to dehydrate other gases, including CO2, H2S, and other oxygenated gases. It is necessary to dry natural gas to a certain point, as humidity in natural gas can cause pipelines to freeze, and create other problems for end users of the natural gas. Triethylene glycol is placed into contact with natural gas, and strips the water out of the gas. Triethylene glycol is heated to a high temperature and put through a condensing system, which removes the water as waste and reclaims the Triethylene glycol for continuous reuse within the system. The waste Triethylene glycol produced by this process has been found to contain enough benzene to be classified as hazardous waste (benzene concentration greater than 0.5 mg/L).

Triethylene glycol is well established as a relatively mild disinfectant toward a variety of bacteria, influenza A viruses and spores of Penicillium notatum fungi. However, its exceptionally low toxicity, broad materials compatibility, and low odor combined with its antimicrobial properties indicates that it approaches the ideal for air disinfection purposes in occupied spaces. Much of the scientific work with triethylene glycol was done in the 1940s and 1950s, however that work has ably demonstrated the antimicrobial activity against airborne, solution suspension, and surface bound microbes. The ability of triethylene glycol to inactivate Streptococcus pneumoniae (original citation: pneumococcus Type I), Streptococcus pyogenes (original citation: Beta hemolytic streptococcus group A) and Influenza A virus in the air was first reported in 1943. Since the first report the following microorganisms have been reported in the literature to be inactivated in the air: Penicillium notatum spores, Chlamydophila psittaci (original citation: meningopneumonitis virus strain Cal 10 and psittacosis virus strain 6BC), Group C streptococcus, type 1 pneumococcus, Staphylococcus albus, Escherichia coli, and Serratia marcescens Bizio (ATCC 274). Solutions of triethylene glycol are known to be antimicrobial toward suspensions of Penicillium notatum spores, Streptococcus pyogenes (original citation: Beta hemolytic streptococcus Group A ), Streptococcus pneumoniae (original citation: pneumococcus Type I), Streptococcus viridans, and Mycobacterium bovis (original citation: tubercle bacilli Ravenel bovine-type). Further, the inactivation of H1N1 influenza A virus on surfaces has been demonstrated. The latter investigation suggests that triethylene glycol may prove to be a potent weapon against future influenza epidemics and pandemics. However, at least some viruses, including Pseudomonas phage phi6 become more infectious when treated with triethylene glycol.

Molar Mass: 150.17 g/mol
CAS #: 112-27-6
Hill Formula: C₆H₁₄O₄
Chemical Formula: HO(CH₂CH₂O)₃H
EC Number: 203-953-2

Four male albino rats weighing 112 to 145 g were given a single oral dose of 22.5 mg randomly radiolabeled 14-C-triethylene glycol. The rats were then placed in a metabolic chamber in which urine, feces, and expired air were collected over a period of 5 days. The radioactivity recovered (in percent of the administered dose) amounted to 0.8 to 1.2% in expired air, 2.0 to 5.3% in feces, and 86.1 to 94.0% in urine. The total recovery of radioactivity was 90.6% to 98.3% of the administered dose.

Following oral dosing, the rat and rabbit excreted most of the triethylene glycol in both unchanged and/or oxidized forms (mono- and dicarboxylic acid derivatives of triethylene glycol). In rabbits dosed with 200 or 2000 mg/kg triethylene glycol respectively excreted 34.3% or 28%, of the administered dose in the urine as unchanged triethylene glycol and 35.2% as a hydroxyacid form of this chemical. In the studies with rats, little if any 14-C-oxalate or 14-C-triethylene glycol in conjugated form was found in the urine. Trace amounts of orally administered 14-C triethylene glycol were excreted in expired air as carbon dioxide (<1%) and in detectable amounts in feces (2 to 5 %). The total elimination of radioactivity (urine, feces and CO2) during the five day period following an oral dose of labeled compound (22.5 mg) ranged from 91 to 98%. The majority of the radioactivity appeared in the urine.

Uses:
Antifreeze
Coolants
Chemical intermediates
Gas dehydration and treating
Heat transfer fluids
Polyester resins
Solvents

Benefits:
Versatile intermediates
Low volatility
Low boiling point
TETRA EG is completely miscible with water and a wide range of organic solvents.

No studies have been reported dealing with the skin absorption of triethylene glycol. Although it is possible that under conditions of very severe prolonged exposures to this chemical, absorption through the skin can occur, it is doubtful any appreciable systemic/dermal injury would occur because triethylene glycol has (1) a low order of dermal irritancy, (2) is not a dermal sensitizer, and (3) showed no evidence of dermal or systemic toxicity following repeated dermal applications of 2 mL (approximately 600 mg/kg) triethylene glycol applied to the skin of rabbits in a 21-day dermal toxicity study.

Two female New Zealand white rabbits triethylene glycol by stomach tube. Urine from the dosed animals was subsequently collected for 24 hrs. Rabbits dosed with 200 or 2,000 mg/kg respectively excreted 34.3% or 28% of the dose amount as unchanged triethylene glycol. The urine of one rabbit contained 35.2% of the administered dose as a hydroxyacid form of triethylene glycol.

Triethylene glycol is believed to be metabolized in mammals by alcohol dehydrogenase to acidic products causing metabolic acidosis. Triethylene glycol metabolism by alcohol dehydrogenase can be inhibited by 4-methyl pyrazole or ethanol.

Triethylene glycol is approved by the Food and Drug Administration (FDA) as a preservative for food packaging adhesives ... . Currently, however, there are no EPA registered products for this use. Triethylene glycol /is also approved as/ an indirect food additive for its use as a plasticizer in cellophane.

Used as a chemical intermediate for the synthesis of iodoxamic acid; rosin ester gum; triethylene glycol bis(3-(3-t-butyl-4-hydroxy-5-methylphenyl)-propionate); triethylene glycol diacetate; triethylene glycol dimethacrylate; triethylene glycol dinitrate; triethylene glycol dipelargonate.

Commercial grade triethylene glycol has been found to contain <1 ppm dioxane. Twenty-six samples of 99.9% pure triethylene glycol were found to contain 0.02 to 0.13% diethylene glycol.

After years of study, triethylene glycol was found to be the ideal chemical for aerial disinfection in sterile filling units because it had a high bactericidal potency at reasonable cost and was non-toxic. It was most effective at relative humidities of 30 to 55% and the rate of kill increased with temperature and degree of saturation of air with the vapor.

Method: NIOSH 5523, Issue 1; Procedure: gas chromatography with a flame ionization detector; Analyte: triethylene glycol; Matrix: air; Detection Limit: 14 ug/sample.

Triethylene glycol has been determined by gas chromatography-mass spectormetry and gas-liquid chromatography. Triethylene glycol has been measured in rat and rabbit urine using vapor phase chromatography and colorimetry.

Residues of triethylene glycol are exempted from the requirement of a tolerance when used as a deactivator in accordance with good agricultural practice as inert (or occasionally active) ingredients in pesticide formulations applied to growing crops only.

The Agency has determined triethylene glycol is eligible for reregistration. Based on the available data, the Agency has concluded that triethylene glycol exhibits low toxicity and exposures to triethylene glycol used as both an active or inert ingredient do not present risks of concern to the Agency. Therefore, no mitigation measures are necessary at this time.

As the federal pesticide law FIFRA directs, EPA is conducting a comprehensive review of older pesticides to consider their health and environmental effects and make decisions about their future use. Under this pesticide reregistration program, EPA examines health and safety data for pesticide active ingredients initially registered before November 1, 1984, and determines whether they are eligible for reregistration. In addition, all pesticides must meet the new safety standard of the Food Quality Protection Act of 1996. Pesticides for which EPA had not issued Registration Standards prior to the effective date of FIFRA '88 were divided into three lists based upon their potential for human exposure and other factors, with List B containing pesticides of greater concern and List D pesticides of less concern. Triethylene glycol is found on List C. Case No: 3146; Pesticide type: insecticide, fungicide, antimicrobial; Case Status: OPP is reviewing data from the pesticide's producers regarding its human health and/or environmental effects, or OPP is determining the pesticide's eligibility for reregistration and developing the RED document.; Active ingredient (AI): triethylene glycol; Data Call-in (DCI) Date(s): 9/30/92; AI Status: The producers of the pesticide have made commitments to conduct the studies and pay the fees required for reregistration, and are meeting those commitments in a timely manner.

Triethylene glycol is an indirect food additive for use only as a component of adhesives.

Triethylene glycol (TEG) is a liquid higher glycol of very low vapor pressure with uses that are primarily industrial. It has a very low order of acute toxicity by iv, ip, peroral, percutaneous and inhalation (vapor and aerosol) routes of exposure. It does not produce primary skin iritation. Acute eye contact with the liquid causes mild local transient irritation (conjunctival hyperemia and slight chemosis) but does not induce corneal injury. Animal maximization and human volunteer repeated insult patch tests studies have shown that TEG does not cause skin sensitization. A study with Swiss-Webster mice demonstrated that TEG aerosol has properties of a peripheral chemosensory irritant material and caused a depression of breathing rate with an RD(50) of 5140 mg/ cu m. Continuous subchronic peroral dosing of TEG in the diet of rats did not produce any systemic cumulative or long-term toxicity. The effects seen were dose-related increased relative kidney weight, increased urine volume and decreased urine pH, probably a result of the renal excretion of TEG and metabolites following the absorption of large doses of TEG. There was also decreased hemoglobin concentration, decreased hematocrit and increased mean corpuscular volume, probably due to hemodilution following absorption of TEG. The NOAEL was 20,000 ppm TEG in diet. Short-term repeated aerosol exposure studies in the rat demonstrated that, by nose-only exposure, the threshold for effects by respiratory tract exposure was 1036 mg/cu m. Neither high dosage acute nor repeated exposures to TEG produce hepatorenal injury characteristic of that caused by the lower glycol homologues. Elimination studies with acute peroral doses of TEG given to rats and rabbits showed high recoveries (91-98% over 5 days), with the major fraction appearing in urine (84-94%) and only 1% as carbon dioxide. TEG in urine is present in unchanged and oxidized forms, but only negligible amounts as oxalic acid. Developmental toxicity studies with undiluted TEG given by gavage produced maternal toxicity in rats (body weight, food consumption, water consumption, and relative kidney weight) with a NOEL of 1126 mg/kg/day, and mice (relative kidney weight) with a NOEL of 5630 mg/kg/day. Developmental toxicity, expressed as fetotoxicity, had a NOEL of 5630 mg/kg/day with the rat and 563 mg/kg/day with mice. Neither species showed any evidence of embryotoxicity or teratogenicity. There was no evidence for reproductive toxicity with mice given up to 3% TEG in drinking water in a continuous breeding study.

TEG did not produce mutagenic or clastogenic effects in the following in vitro genetic toxicology studies: Salmonella typhimurium reverse mutation test, SOS-chromotest in E. coli, CHO forward gene mutation test (HGPRT locus), CHO sister chromatid exchange test, and a chromosome aberration test with CHO cells. The use patterns suggest that exposure to TEG is mainly occupational, with limited exposures by consumers. Exposure is normally by skin and eye contact. Local and systemic adverse health effects by cutaneous exposure are likely not to occur, and eye contact will produce transient irritation without corneal injury. The very low vapor pressure of TEG makes it unlikely that significant vapor exposure will occur. Aerosol exposure is not a usual exposure mode, and acute aerosol exposures are unlikely to be harmful, although a peripheral sensory irritant effect may develop. However, repeated exposures to a TEG aerosol may result in respiratory tract irritation, with cough, shortness of breath and tightness of the chest. Recommended protective and precautionary measures include protective gloves, goggles or safety glasses and mechanical room ventilation. LC(50) data to various fish, aquatic invertebrates and algae, indicate that TEG is essentially nontoxic to aquatic organisms. Also, sustained exposure studies have demonstrated that TEG is of a low order of chronic aquatic toxicity. The bioconcentration potential, environmental hydrolysis, and photolysis rates are low, and soil mobility high. In the atmosphere TEG is degraded by reacting with photochemically produced hydroxyl radicals. These considerations indicate that the potential for ecotoxicological effects with TEG is low.

A 23-yr-old woman was brought to an emergency room after intentionally ingesting one gulp (volume unspecified) of ... brake fluid. ...The patient was given milk to drink by her family and subsequently vomited. Upon arrival to the emergency room, she was unconscious and had metabolic acidoses (pH 7.03, PCO2 44 mmHg, bicarbonate 11 mmol/L, anion gap 30 mmol/L, serum creatinine 90 umol/L). She was intubated and given 100 mmol of iv sodium bicarbonate. Triethylene glycol is thought to be metabolized by alcohol dehydrogenase to acidic products resulting in metabolic acidosis. To act as a competitor of the alcohol dehydrogenase enzyme, ethanol was administered to maintain a serum ethanol level of 100 mg/dL. The blood pH returned to normal over the next 8 hrs, and ethanol infusion was continued for 22 hr. At 36 hr post ingestion, the patient was discharged to a psychiatric ward. Analysis of blood drawn upon admission did not detect the presence of ethanol, ethylene glycol, methanol... . The above case study described the... brake fluid as 99.9% triethylene glycol. The material safety data sheet for /this brand of/ brake fluid, however, lists its ingredients as 30-60% polyglycol ethers; 30-60% borate of triethylene glycol monomethyl ether; 30-60% polyglycol; 0-10% corrosion inhibitor; and 0-10% dye.

The metabolism of triethylene glycol was evaluated in groups of rats (number and sex not reported) orally administered (gavage or diet not specified) 1.2 g/kg. The proportion of the dose that was excreted in the urine unchanged was 59% and 3.8% at days 1 and 2 post-dosing, respectively. The procedure for recovery of triethylene glycol from the urine was not reported. No metabolites of the test compound were identified.

A perinatal/postnatal teratology study was conducted with 50 pregnant Specific Pathogen Free CD-1 albino mice administered triethylene glycol by oral gavage at a dose level of 11270 mg/kg/day (the maximum tolerated dose calculated from a previous study) on gestation days 7-14. Mortality was not observed and no pharmacotoxic signs were observed except for a roughened haircoat in 1 animal. Statistical analysis were determined by the Student's t-test (p<0.05). The mean maternal body weights and the mean weight change (Day 18-7) were significantly lower than control values. Mean pup counts and offspring viability were similiar to controls. Although mean pup weights were significantly lower than the control weights at birth, mean pup weights at day 3 were comparable to controls. No apparent adverse effects on reproductive or neonatal outcome were observed. Gross necropsy observations were not reported.

Reproductive toxicity was evaluated in groups of 10 pregnant Charles River CD female mice receiving an oral gavage dose of triethylene glycol at 10 ml/kg body weight on gestation days 7 through 14. Maternal mortality was approximatedly 4% of the test group. Clinical observations and gross necropsy were not reported. There was a significant reduction (p<0.05) in the number of live pups per litter, reduced survival, and reduced birth weight among offspring of treated dams.

Triethylene glycol's production and use a fragrance ingredient in cosmetics, as a solvent, plasticizer in vinyl, polyester and polyurethane resins, as a humectant in printing inks, and in the dehydration of natural gas may result in its release to the environment through various waste streams; it's use as a bacteriostat and as an inert ingredient to facilitate delivery of formulated pesticide products will result in its direct release to the environment. If released to air, a vapor pressure of 1.32X10-3 mm Hg at 25 °C indicates triethylene glycol will exist solely as a vapor in the atmosphere. Vapor-phase triethylene glycol will be degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals; the half-life for this reaction in air is estimated to be 11 hours. Alcohols and ethers do not absorb light at wavelengths >290 nm and therefore triethylene glycol is not expected to be susceptible to direct photolysis by sunlight. If released to soil, triethylene glycol is expected to have very high mobility based upon an estimated Koc of 10. Volatilization from moist soil surfaces is not expected to be an important fate process based upon an estimated Henry's Law constant of 3.2X10-11 atm-cu m/mole. River die-away test data demonstrate that biodegradation is likely to be the most important removal mechanism of triethylene glycol from aerobic soil and water; complete degradation in river die-away studies required 7-11 days. If released into water, triethylene glycol is not expected to adsorb to suspended solids and sediment based upon the estimated Koc. Volatilization from water surfaces is not expected to be an important fate process based upon this compound's estimated Henry's Law constant. An estimated BCF of 3 suggests the potential for bioconcentration in aquatic organisms is low. Hydrolysis is not expected to be an important environmental fate process since this compound lacks functional groups that hydrolyze under environmental conditions. Occupational exposure to triethylene glycol may occur through inhalation and dermal contact with this compound at workplaces where triethylene glycol is produced or used. Monitoring and use data indicate that the general population may be exposed to triethylene glycol via inhalation of ambient air, and dermal contact with products containing triethylene glycol.

Triethylene glycol's production and use as a solvent, plasticizer in vinyl, polyester and polyurethane resins, as a humectant in printing inks, in the dehydration of natural gas(1) and as a fragrance ingredient in cosmetics(2) may result in its release to the environment through various waste streams; it's use as a bacteriostat and as an inert ingredient to facilitate delivery of formulated pesticide products(3) will result in its direct release to the environment(SRC).

Based on a classification scheme(1), an estimated Koc value of 10(SRC), determined from a structure estimation method(2), indicates that triethylene glycol is expected to have very high mobility in soil(SRC). Volatilization of triethylene glycol from moist soil surfaces is not expected to be an important fate process(SRC) given an estimated Henry's Law constant of 3.2X10-11 atm-cu m/mole(SRC), using a fragment constant estimation method(3). Triethylene glycol is not expected to volatilize from dry soil surfaces(SRC) based upon a vapor pressure of 1.32X10-3 mm Hg(4). A series of aerobic river die-away tests which utilized several different sources of freshwater, suggest that rapid biodegradation is likely to be the most important removal mechanism of triethylene glycol from aerobic soil(SRC); degradation was complete within 7-11 days(5).

Based on a classification scheme(1), an estimated Koc value of 10(SRC), determined from a structure estimation method(2), indicates that triethylene glycol is not expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is not expected(3) based upon an estimated Henry's Law constant of 3.2X10-11 atm-cu m/mole(SRC), developed using a fragment constant estimation method(4). According to a classification scheme(5), an estimated BCF of 3(SRC), from an estimated log Kow of -1.75(6) and a regression-derived equation(7), suggests the potential for bioconcentration in aquatic organisms is low(SRC). A series of aerobic river die-away tests, which utilized several differing sources of freshwater, suggest that rapid aerobic biodegradation is likely to be the most important removal mechanism of triethylene glycol from aquatic systems(SRC); degradation was complete within 7-11 days(8).

According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), triethylene glycol, which has a vapor pressure of 1.32X10-3 mm Hg at 25 °C(2), is expected to exist solely as a vapor in the ambient atmosphere. Vapor-phase triethylene glycol is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals(SRC); the half-life for this reaction in air is estimated to be 11 hours(SRC), calculated from its rate constant of 3.6X10-11 cu cm/molecule-sec at 25 °C(SRC) that was derived using a structure estimation method(3). Alcohols and ethers do not absorb light at wavelengths >290 nm and therefore triethylene glycol is not expected to be susceptible to direct photolysis by sunlight(4).

Aerobic river die-away tests, utilizing several different sources of freshwater, have demonstrated that triethylene glycol should biodegrade rapidly in the environment(1). At 20 °C, the degradation of 10 mg/L triethylene glycol was complete within 7-11 days(1). 25 to 92% of the theoretical BOD was reached within 4 weeks incubation during the MITI test using a sludge inoculum; these results were on an upward trend by the end of the test(2) indicating that acclimation may be important for this compound(SRC). Triethylene glycol degraded 85% of theoretical BOD (1.6 gm/gm) after 20 days at 20 °C(3).

The rate constant for the vapor-phase reaction of triethylene glycol with photochemically-produced hydroxyl radicals has been estimated as 3.6X10-11 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1). This corresponds to an atmospheric half-life of about 11 hours at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1). Triethylene glycol is not expected to undergo hydrolysis in the environment due to the lack of functional groups that hydrolyze under environmental conditions(2,3). Alcohols and ethers do not absorb light at wavelengths >290 nm and therefore triethylene glycol is not expected to be susceptible to direct photolysis by sunlight(4).

An estimated BCF of 3 was calculated in fish for triethylene glycol(SRC), using an estimated log Kow of -1.75(1) and a regression-derived equation(2). According to a classification scheme(3), this BCF suggests the potential for bioconcentration in aquatic organisms is low(SRC).

The Henry's Law constant for triethylene glycol is estimated as 3.2X10-11 atm-cu m/mole(SRC) using a fragment constant estimation method(1). This Henry's Law constant indicates that triethylene glycol is expected to be essentially nonvolatile from water surfaces(2). Triethylene glycol is not expected to volatilize from dry soil surfaces(SRC) based upon a vapor pressure of 1.32X10-3 mm Hg(3).

Triethylene glycol was found in 5 of 25 aerosol samples taken from a light house site in northeastern Puerto Rico, and was identified in a sample taken 30 miles off the south coast(1).

NIOSH (NOES Survey 1981-1983) has statistically estimated that 233,613 workers (53,367 of these are female) are potentially exposed to triethylene glycol in the US(1). Occupational exposure to triethylene glycol may occur through inhalation and dermal contact with this compound at workplaces where triethylene glycol is produced or used(SRC). Monitoring and use data indicate that the general population may be exposed to triethylene glycol via inhalation of ambient air, and dermal contact with products containing triethylene glycol(SRC).

Application
Triethylene glycol can be used:
• To prepare fatty acid gelators, which are used to gelate various edible and vegetable oils.
• As a solvent to prepare superparamagnetic iron oxide nanoparticles for in situ protein purification.
• As an absorbent agent in the subsea natural gas dehydration process.

Triethylene glycol (TEG) is a colorless, viscous liquid with a slight odor. It is non-flammable, mildly toxic, and considered non-hazardous. TEG is a member of a homologous series of dihydroxy alcohols. It is used as a plasticizer for vinyl polymers as well as in the manufacture of air sanitizer and other consumer products.

Triethylene Glycol (TEG) is a liquid chemical compound with the molecular formula C6H14O4 or HOCH2CH2CH2O2CH2OH. Its CAS is 112-27-6. TEG is recognized for its hygroscopic quality and ability to dehumidify fluids. It is miscible with water and soluble in ethanol, acetone, acetic acid, glycerine, pyridine, and aldehydes. It is slightly soluble in diethyl ether, and insoluble in oil, fat, and most hydrocarbons.

TEG is commercially produced as a co-product of the oxidation of ethylene at a high temperature in the presence of silver oxide catalyst, followed by hydration of ethylene oxide to yield mono, di, tri, and tetraethylene glycols.

The oil and gas industries use TEG to dehydrate natural gas as well as other gases including CO2, H2S, and other oxygenated gases. Industrial uses include adsorbents and absorbents, functional fluids in both closed and open systems, Intermediates, petroleum production processing aids, and solvents. TEG is used in the manufacture of a host of consumer products that include anti-freeze, automotive care products, building and construction materials, cleaning and furnishing care products, fabric, textile, and leather products, fuels and related products, lubricants and greases, paints and coatings, personal care products, and plastic and rubber products.

Triethylene Glycol is widely used as a solvent. It has a high flash point, emits no toxic vapors, and is not absorbed through the skin.

Characteristics
Triethylene glycol is viscous at room temperature. It is colorless, odorless, and sweet-tasting. It is miscible in water in all ratios.

Triethylene Glycol (TEG) is a larger molecule than MEG, DEG and has two ether groups. It is less clear and less hygroscopic than DEG, but has a higher boiling point, density and viscosity.

PROPERTIES

Triethylene glycol is a member of a homologous series of dihydroxy alcohols. It is a colorless, odorless and stable liquid with high viscosity and a high boiling point. Apart from its use as a raw material in the manufacture and synthesis of other products, triethylene glycol is known for its hygroscopic quality and its ability to dehumidify fluids. This liquid is miscible with water, and at a pressure of 101.325 kPa has a boiling point of 286.5°C and a freezing point of -7°C.
Triethylene glycol (TEG) is a liquid chemical compound with the molecular formula C6H14O4. Triethylene glycol is recognized for its hygroscopic quality and ability to dehumidify fluids. It is miscible with water and soluble in ethanol, acetone, acetic acid, glycerine, pyridine, and aldehydes. It is slightly soluble in diethyl ether, and insoluble in oil, fat, and most hydrocarbons.

CHEMICAL AND PHYSICAL PROPERTIES OF TRIETHYLENE GLYCOL

Triethylene glycol’s molecule formula: C6-H14-O4
Triethylene glycol’s molecular weight: 150.17
Triethylene glycol’s colour/form: colourless, liquid
Triethylene glycol’s odor: practically odorless
Triethylene glycol’s boiling point: 285°C; 165 °C at 14 mm Hg
Triethylene glycol’s melting point: -7°C
Triethylene glycol’s density: 1.1274 at 15°C/4 °C
Triethylene glycol’s heat of vaporization: 61.04 kJ/mol at 101.3 kPa /=760 mm Hg/
Triethylene glycol’s octanol/water partition coefficient: log Kow = -1.98
Triethylene glycol’s solubility: Miscible with alcohol, benzene, toluene; sparingly sol in ether; practically insol in petroleum ether. Soluble in oxygenated solvents. Slightly soluble in ethyl ether, chloroform; insoluble in petroleum ether. In water, miscible.
Triethylene glycol’s vapor pressure: 1.32X10-3 mm Hg at 25°C (est)
Triethylene glycol’s viscosity: 47.8 cP at 20°C
Triethylene glycol’s flash point: 350°F (177°C) (Open cup)
Triethylene glycol’s flammable limits: Lower flammable limit: 0.9% by volume; Upper flammable limit: 9.2% by volume
Triethylene glycol’s autoignition temperature: 700°F (371°C)

PREPARATIONS OF TRIETHYLENE GLYCOL

Triethylene glycol is prepared commercially as a co-product of the oxidation of ethylene at high temperature in the presence of silver oxide catalyst, followed by hydration of ethylene oxide to yield mono(one)-, di(two)-, tri(three)- and tetraethylene glycols.

METHODS OF MANUFACTURING OF TRIETHYLENE GLYCOL

Prepared from ethylene oxide and ethylene glycol in presence of sulfuric acid ... manufactured by forming ether-ester of hydroxyacetic acid with glycol and then hydrogenating.

Produced commercially as by-product of ethylene glycol production. Triethylene glycol's formation is favored by a high ethylene oxide to water ratio.

Diethylene glycol + ethylene oxide (epoxidation)

Ethylene glycol monoethers are usually produced by reaction of ethylene oxide with the appropriate alcohol. A mixture of homologues is obtained. The glycol monoethers can be converted to diethers by alkylation with common alkylating agents, such as dimethyl sulfate or alkyl halides (Williamson synthesis). Glycol dimethyl ethers are formed by treatment of dimethyl ether with ethylene oxide. /Ethers/

GENERAL MANUFACTURING INFORMATION ABOUT TRIETHYLENE GLYCOL

Triethylene glycol is described as an oligomer of ethylene glycol. So-called polyglycols are higher molecular weight adducts of ethylene oxide and distinguised by intervening ether linkages in the hydrocarbon chain. After years of study, triethylene glycol was found to be the ideal chemical for aerial disinfection in sterile filling units because triethylene glycol had a high bactericidal potency at reasonable cost and was non-toxic. triethylene glycol was most effective at relative humidities of 30 to 55% and the rate of kill increased with temperature and degree of saturation of air with the vapor.

APPLICATIONS OF TRIETHYLENE GLYCOL

Triethylene glycol is used by the oil and gas industry to "dehydrate" natural gas. It may also be used to dehydrate other gases, including CO2, H2S, and other oxygenated gases. It is necessary to dry natural gas to a certain point, as humidity in natural gas can cause pipelines to freeze, and create other problems for end users of the natural gas. Triethylene glycol is placed into contact with natural gas, and strips the water out of the gas. Triethylene glycol is heated to a high temperature and put through a condensing system, which removes the water as waste and reclaims the triethylene glycol for continuous reuse within the system. The waste triethylene glycol produced by this process has been found to contain enough benzene to be classified as hazardous waste (benzene concentration greater than 0.5 mg/L).

The oil and gas industries use triethylene glycol to dehydrate natural gas as well as other gases including CO2, H2S, and other oxygenated gases. Industrial uses include adsorbents and absorbents, functional fluids in both closed and open systems, Intermediates, petroleum production processing aids, and solvents. Triethylene glycol is used in the manufacture of a host of consumer products that include anti-freeze, automotive care products, building and construction materials, cleaning and furnishing care products, fabric, textile, and leather products, fuels and related products, lubricants and greases, paints and coatings, personal care products, and plastic and rubber products.

HUMAN HEALTH EFFECTS
TOXICITY SUMMARY

Triethylene glycol (TEG) is a liquid higher glycol of very low vapor pressure with uses that are primarily industrial. It has a very low order of acute toxicity by iv, ip, peroral, percutaneous and inhalation (vapor and aerosol) routes of exposure. It does not produce primary skin iritation. Acute eye contact with the liquid causes mild local transient irritation (conjunctival hyperemia and slight chemosis) but does not induce corneal injury. Animal maximization and human volunteer repeated insult patch tests studies have shown that triethylene glycol does not cause skin sensitization. A study with Swiss-Webster mice demonstrated that triethylene glycol aerosol has properties of a peripheral chemosensory irritant material and caused a depression of breathing rate with an RD(50) of 5140 mg/cu m. Continuous subchronic peroral dosing of triethylene glycol in the diet of rats did not produce any systemic cumulative or long-term toxicity. The effects seen were dose-related increased relative kidney weight, increased urine volume and decreased urine pH, probably a result of the renal excretion of triethylene glycol and metabolites following the absorption of large doses of triethylene glycol. There was also decreased hemoglobin concentration, decreased hematocrit and increased mean corpuscular volume, probably due to hemodilution following absorption of triethylene glycol. The NOAEL was 20,000 ppm triethylene glycol in diet. Short-term repeated aerosol exposure studies in the rat demonstrated that, by nose-only exposure, the threshold for effects by respiratory tract exposure was 1036 mg/cu m. Neither high dosage acute nor repeated exposures to triethylene glycol produce hepatorenal injury characteristic of that caused by the lower glycol homologues. Elimination studies with acute peroral doses of triethylene glycol given to rats and rabbits showed high recoveries (91-98% over 5 days), with the major fraction appearing in urine (84-94%) and only 1% as carbon dioxide. triethylene glycol in urine is present in unchanged and oxidized forms, but only negligible amounts as oxalic acid.

Developmental toxicity studies with undiluted triethylene glycol given by gavage produced maternal toxicity in rats (body weight, food consumption, water consumption, and relative kidney weight) with a NOEL of 1126 mg/kg/day, and mice (relative kidney weight) with a NOEL of 5630 mg/kg/day. Developmental toxicity, expressed as fetotoxicity, had a NOEL of 5630 mg/kg/day with the rat and 563 mg/kg/day with mice. Neither species showed any evidence of embryotoxicity or teratogenicity. There was no evidence for reproductive toxicity with mice given up to 3% triethylene glycol in drinking water in a continuous breeding study. triethylene glycol did not produce mutagenic or clastogenic effects in the following in vitro genetic toxicology studies: Salmonella typhimurium reverse mutation test, SOS-chromotest in E. coli, CHO forward gene mutation test (HGPRT locus), CHO sister chromatid exchange test, and a chromosome aberration test with CHO cells. The use patterns suggest that exposure to triethylene glycol is mainly occupational, with limited exposures by consumers. Exposure is normally by skin and eye contact. Local and systemic adverse health effects by cutaneous exposure are likely not to occur, and eye contact will produce transient irritation without corneal injury.

The very low vapor pressure of triethylene glycol makes it unlikely that significant vapor exposure will occur. Aerosol exposure is not a usual exposure mode, and acute aerosol exposures are unlikely to be harmful, although a peripheral sensory irritant effect may develop. However, repeated exposures to a triethylene glycol aerosol may result in respiratory tract irritation, with cough, shortness of breath and tightness of the chest. Recommended protective and precautionary measures include protective gloves, goggles or safety glasses and mechanical room ventilation. LC(50) data to various fish, aquatic invertebrates and algae, indicate that triethylene glycol is essentially nontoxic to aquatic organisms. Also, sustained exposure studies have demonstrated that triethylene glycol is of a low order of chronic aquatic toxicity. The bioconcentration potential, environmental hydrolysis, and photolysis rates are low, and soil mobility high. In the atmosphere triethylene glycol is degraded by reacting with photochemically produced hydroxyl radicals. These considerations indicate that the potential for ecotoxicological effects with triethylene glycol is low.

ENVIRONMENTAL FATE & EXPOSURE

Volatilization from moist soil surfaces is not expected to be an important fate process based upon an estimated Henry's Law constant of 3.2X10-11 atm-cu m/mole. River die-away test data demonstrate that biodegradation is likely to be the most important removal mechanism of triethylene glycol from aerobic soil and water; complete degradation in river die-away studies required 7-11 days. If released into water, triethylene glycol is not expected to adsorb to suspended solids and sediment based upon the estimated Koc. Volatilization from water surfaces is not expected to be an important fate process based upon this compound's estimated Henry's Law constant. An estimated BCF of 3 suggests the potential for bioconcentration in aquatic organisms is low. Hydrolysis is not expected to be an important environmental fate process since triethylene glycol lacks functional groups that hydrolyze under environmental conditions. Occupational exposure to triethylene glycol may occur through inhalation and dermal contact with this compound at workplaces where triethylene glycol is produced or used. Monitoring and use data indicate that the general population may be exposed to triethylene glycol via inhalation of ambient air, and dermal contact with products containing triethylene glycol.