PPG 4000

PPG 4000

CAS No. : 25322-69-4
EC No. : 500-039-8

Synonyms:
Polypropylene glycol (15); Polypropylene glycol (17); Polypropylene glycol (20); Polypropylene glycol (26); Polypropylene glycol (30); Polypropylene glycol (34); Polypropylene glycol 4000; Polypropylene glycol 2025; Polypropylene glycol 3025; Polypropylene glycol 4000; Polypropylene glycol 4025; P.P.G. 4000; P.P.G. 1025; P.P.G. 1200; P.P.G. 1800; WNY0H4G53Q; Polypropylene glycol #4000; Polypropylene glycol #1800; Propylene glycol; α-Propylene glycol; 1,2-Propanediol; 1,2-Dihydroxypropane; POLYPROPYLENE GLYCOL 4000; Methyl ethyl glycol; Methylethylene glycol; 2-(2-Hydroxypropoxy)-1-propanol; 2-(2-Hydroxypropoxy) propanol; alpha-Hydro-omega-hydroxypoly (oxy(methyl-1,2-ethanediyl)); alpha-Hydro-omega-hydroxypoly (oxypropylene); Desmophen 360C; Emkapyl; Jeffox PPG 400; Laprol 2002; Laprol 702; Lineartop e; Actocol 51-530; Alkapal PPG-4000; alpha-Hydro-omega-hydroxypoly(oxy(methyl-1,2-ethanediyl)); alpha-Hydro-omega-hydroxypoly(oxypropylene); Bloat guard; Caswell No. 680; Desmophen 360C; EC 500-039-8; Emkapyl; EPA Pesticide Chemical Code 068602; Glycols, polypropylene; HSDB 1266; Jeffox PPG 400; Laprol 2002; Lineartop E; Methyloxirane homopolymer; Napter E 8075; Niax 1025; Niax 11-27; Niax 61-582; Niax polyol ppg 4025; Niax ppg; Oopg 4000; Oxirane, methyl-, homopolymer; P 400; P 4000 (polymer); P.P.G. 400; Pluracol 1010; PPG 4000; Pluracol P 410; Poly(oxy(methyl-1,2-ethanediyl)), alpha-hydro-omega-hydroxy-; Poly(propylene oxide); Polyglycol P 400; Polyglycol P-4000; Polyglycol type P4000; Polyglycol type P400; Polymer 2; Polyoxypropylene; Polyoxypropylene glycol; Polypropylene glycol; Polypropylene glycol #400; Polypropylenglykol; Polypropylenglykol [Czech]; PPG; PPG-15; Propylan 8123; Propylene oxide homopolymer; Propylene oxide, propylene glycol polymer; SKF 18667; Voranol P 1010; Voranol P 4000; Voranol P 4000; Poly(propylene oxide); Niax ppg 425; Jeffox PPG 400; Polyglycol P-4000; Polyglycol P-4000; Laprol 2002; Niax ppg 1025; Niax ppg 3025; Polyoxypropylene (12); Polyglycol type P250; Polyglycol type P400; Polyglycol type P750; Voranol P 1010; Napter E 8075; 1-Propanol, 2-(2-hydroxypropoxy)-; Polymer 2; Niax polyol ppg 4025; Polyglycol type P1200; Polyglycol type P4000; Polyglycol type P3000; Propylene oxide homopolymer; Pluracol 1010; Pluracol 2010; Pluracol P 410; Propylan 8123; Laprol 702; 2-(2-Hydroxypropoxy)propanol; Caswell No. 680; Glycols, polypropylene; Pluracol P 2010; Voranol P 4000; Voranol P 4000; Polypropylene Glycol 400; PPG 4000; Polypropylene Glycol 4000; Polypropylene Glycol 4000; Alkapal PPG-1200; POLYPROPYLENE GLYCOL 4000; Alkapal PPG-4000; Alkapal PPG-4000; Actocol 51-530; P 4000 (polymer); Polypropylenglykol [Czech]; alpha-Hydro-omega-hydroxypoly(oxypropylene); Niax 1025; Oopg 4000; Polypropylene glycol #400; Polypropylene glycol #425; Polypropylene glycol #750; Polypropylene glycol 1025; Niax 11-27; PPG-9; Polypropylene glycol #1200; Niax 61-582; Oxirane, methyl-, homopolymer; PPG-12; PPG-15; PPG-17; PPG-20; PPG-26; PPG-30; PPG-34; Propylene oxide, propylene glycol polymer; Polyoxypropylene (9); HSDB 1266; Polyoxypropylene (12); Polyoxypropylene (15); Polyoxypropylene (17); Polyoxypropylene (20); Polyoxypropylene (26); Polyoxypropylene (30); Polyoxypropylene (34); Polypropylene glycol (9); Polypropylene glycol 150; SKF 18667; ARCOL POLYOL PPG-4000; polyether polyol; PPG; Poly(propylene oxide); polypropyleneglycol; Poly(propylene glycol); Propane-1,2-diol; Poly(oxypropylene); Polypropylene glycol; 2-(2-hydroxypropoxy)propan-1-ol; Polyoxypropylene; 2-(2-HYDROXYPROPOXY)-1-PROPANOL; Emkapyl; Lineartop E; Niax ppg; Polyoxypropylene glycol; 106-62-7; Methyloxirane homopolymer; Desmophen 360C; Polyglycol P 400; EPA Pesticide Chemical Code 068602; P.P.G 2025; P.P.G 3025; P.P.G 4025; P.P.G. 150; P.P.G. 400; P.P.G. 425; P.P.G. 750; Polypropylene glycol (12); alpha-Hydro-omega-hydroxypoly(oxy(methyl-1,2-ethanediyl)); P 400; Polypropylene glycol (m w 1,200-3,000); Poly(oxy(methyl-1,2-ethanediyl)), alpha-hydro-omega-hydroxy-; Polypropylenglykol; Poly(propylene glycol), average M.W. 425; Propane-1,2-diol, propoxylated; Poly(propylene glycol); Poly(propylene glycol), average M.W. 2.000; Poly(propylene glycol), average M.W. 4.000; polypropylene oxide; EINECS 203-416-2; PPG?; 2-Methyl-3-oxahexane-1,5-diol; poly(propylene glycol) macromolecule; Dipropylene Glycol,mixture of isomers

PPG 4000

PPG 4000 is clear, colorless, slightly syrupy liquid at room temperature. It may exist in air in the vapor form, although PPG 4000 must be heated or briskly shaken to produce a vapor. PPG 4000 is practically odorless and tasteless.
PPG-4000 is a bifunctional polyether polyol. Suitable for the production of polyurethane adhesives. Shelf life of ARCOL POLYOL PPG-4000 is 12 months.

What is PPG 4000?
PPG 4000 is a synthetic liquid substance that absorbs water. PPG 4000 is also used to make polyester compounds, and as a base for deicing solutions. PPG 4000 is used by the chemical, food, and pharmaceutical industries as an antifreeze when leakage might lead to contact with food. The Food and Drug Administration (FDA) has classified PPG 4000 as an additive that is "generally recognized as safe" for use in food. It is used to absorb extra water and maintain moisture in certain medicines, cosmetics, or food products. It is a solvent for food colors and flavors, and in the paint and plastics industries. PPG 4000 is also used to create artificial smoke or fog used in fire-fighting training and in theatrical productions. Other names for PPG 4000 are 1,2-dihydroxypropane, 1,2-propanediol, methyl glycol, and trimethyl glycol.

Laboratory
S-Propanediol is synthesized from via fermentation methods. Lactic acid and lactaldehyde are common intermediates. Dihydroxyacetone phosphate, one of the two products of breakdown (glycolysis) of fructose 1,6-bisphosphate, is a precursor to methylglyoxal. This conversion is the basis of a potential biotechnological route to the commodity chemical 1,2-propanediol. Three-carbon deoxysugars are also precursor to the 1,2-diol.[4]

Applications
Polymers
Forty-five percent of PPG 4000 produced is used as a chemical feedstock for the production of unsaturated polyester resins. In this regard, PPG 4000 reacts with a mixture of unsaturated maleic anhydride and isophthalic acid to give a copolymer. This partially unsaturated polymer undergoes further crosslinking to yield thermoset plastics. Related to this application, PPG 4000 reacts with propylene oxide to give oligomers and polymers that are used to produce polyurethanes.[4] PPG 4000 is used in waterbased acrylic architectural paints to extend dry time which it accomplishes by preventing the surface from drying due to its slower evaporation rate compared to water.

Food
PPG 4000 is also used in various edible items such as coffee-based drinks, liquid sweeteners, ice cream, whipped dairy products and soda. Vaporizers used for delivery of pharmaceuticals or personal-care products often include PPG 4000 among the ingredients. In alcohol-based hand sanitizers, it is used as a humectant to prevent the skin from drying.[11] PPG 4000 is used as a solvent in many pharmaceuticals, including oral, injectable, and topical formulations. Many pharmaceutical drugs which are insoluble in water utilize PPG 4000 as a solvent and carrier; benzodiazepine tablets are one example.[12] PPG 4000 is also used as a solvent and carrier for many pharmaceutical capsule preparations. Additionally, certain formulations of artificial tears use proplyene glycol as an ingredient.

PPG 4000 is commonly used to de-ice aircraft
Antifreeze
The freezing point of water is depressed when mixed with PPG 4000. It is used as aircraft de-icing fluid.[4][14] Water-PPG 4000 mixtures dyed pink to indicate the mixture is relatively nontoxic are sold under the name of RV or marine antifreeze. PPG 4000 is frequently used as a substitute for ethylene glycol in low toxicity, environmentally friendly automotive antifreeze. It is also used to winterize the plumbing systems in vacant structures.[15] The eutectic composition/temperature is 60:40 PPG 4000:water/-60 °C. The −50 °F/−45 °C commercial product is, however, water rich; a typical formulation is 40:60.[18]

Electronic cigarettes liquid
PPG 4000 is often used in electronic cigarettes.
Along with vegetable glycerin as the main ingredient (<1–92%) in e-liquid used in electronic cigarettes, where it is aerosolized to resemble smoke. It serves as both the carrier for substances like nicotine and cannabinoids, as well as for creating a vapor which resembles smoke.

FEATURES
May also be included as a component in other urethane products & applications.
Coatings
Adhesives
Sealants
Elastomers

Polypropylene glycols are liquids, mostly insoluble in water, used to suppress foaming in industrial processes and for making polyurethane resins, hydraulic fluids, and various other materials.
PPG 4000 or polypropylene oxide is the polymer of propylene glycol. Chemically it is a polyether, and, more generally speaking, it's a polyalkylene glycol (PAG). The term PPG 4000 or PPG 4000 is reserved for low to medium range molar mass polymer when the nature of the end-group, which is usually a hydroxyl group, still matters. The term "oxide" is used for high molar mass polymer when end-groups no longer affect polymer properties. In 2003, 60% of the annual production of propylene oxide of 6.6×106 tonnes was converted into the polymer.

Miscellaneous applications
A bottle of flavored e-liquid for vaping shows PPG 4000 as one of the main ingredients along with vegetable glycerin.
PPG 4000 (often abbreviated 'PPG') has many applications. Some common applications see PPG 4000 used:
As a solvent for many substances, both natural and synthetic.
As a humectant (E1520).
As a freezing point depressant for slurry ice.
In veterinary medicine as an oral treatment for hyperketonaemia in ruminants.
In the cosmetics industry, where PPG 4000 is very commonly used as a carrier or base for various types of makeup.
For trapping and preserving insects (including as a DNA preservative).[23]
For the creation of theatrical smoke and fog in special effects for film and live entertainment. So-called 'smoke machines' or 'hazers' vaporize a mixture of PPG 4000 and water to create the illusion of smoke. While many of these machines use a PPG 4000-based fuel, some use oil. Those which use PPG 4000 do so in a process that is identical to how electronic cigarettes work; utilizing a heating element to produce a dense vapor. The vapor produced by these machines has the aesthetic look and appeal of smoke, but without exposing performers and stage crew to the harms and odors associated with actual smoke.
As an additive in PCR to reduce the melting temperature of nucleic acids for targeting of GC rich sequences.

1.2 What happens to PPG 4000 when it enters the environment?
Waste streams from the manufacture of PPG 4000 are primarily responsible for the releases into the air, water, and soil. PPG 4000 can enter the environment when it is used as a runway and aircraft de-icing agent. PPG 4000 can also enter the environment through the disposal of products that contains it. It is not likely to exist in large amounts in the air. We have little information about what happens to PPG 4000 in the air. The small amounts that may enter the air are likely to break down quickly. If it escapes into the air, it will take between 24 and 50 hours for half the amount released to break down. PPG 4000 can mix completely with water and can soak into soil. It can break down relatively quickly (within several days to a week) in surface water and in soil. PPG 4000 can also travel from certain types of food packages into the food in the package.

1.3 How might I be exposed to PPG 4000?
PPG 4000 has been approved for use at certain levels in food, cosmetics, and pharmaceutical products. If you eat food products, use cosmetics, or take medicines that contain it, you will be exposed to PPG 4000, but these amounts are not generally considered harmful. People who work in industries that use PPG 4000 may be exposed by touching these products or inhaling mists from spraying them. These exposures tend to be at low levels, however. PPG 4000 is used to make artificial smoke and mists for fire safety training, theatrical performances, and rock concerts. These artificial smoke products may also be used by private citizens. These products are frequently used in enclosed spaces, where exposure may be more intense.

1.4 How can PPG 4000 ether enter and leave my body?
PPG 4000 can enter your bloodstream if you breathe air containing mists or vapors from this compound. It can also enter your bloodstream through your skin if you come in direct contact with it and do not wash it off. If you eat products that contain PPG 4000, it may enter your bloodstream. Exposure of the general population to PPG 4000 is likely since many foods, drugs, and cosmetics contain it.
PPG 4000 breaks down in the body in about 48 hours. However, studies of people and animals show that if you have repeated eye, skin, nasal, or oral exposures to PPG 4000 for a short time, you may develop some irritation.

1.5 How can PPG 4000 affect my health?
PPG 4000 breaks down at the same rate as ethylene glycol, although it does not form harmful crystals when it breaks down. Frequent skin exposure to PPG 4000 can sometimes irritate the skin.

1.6 Is there a medical test to determine whether I have been exposed to PPG 4000?
PPG 4000 is generally considered to be a safe chemical, and is not routinely tested for, unless specific exposure, such as to a medicine or cosmetic, can be linked with the observed bad symptoms. Since PPG 4000 breaks down very quickly in the body, it is very difficult to detect.

1.7 What recommendations has the federal government made to protect human health?
The government has developed regulations and guidelines for PPG 4000. These are designed to protect the public from potential adverse health effects.
The Food and Drug Administration (FDA) has classified PPG 4000 as "generally recognized as safe," which means that it is acceptable for use in flavorings, drugs, and cosmetics, and as a direct food additive. According to the World Health Organization, the acceptable dietary intake of PPG 4000 is 25 mg of PPG 4000 for every kilogram (kg) of body weight.

Polymerization
PPG 4000 is produced by ring-opening polymerization of propylene oxide. The initiator is an alcohol and the catalyst a base, usually potassium hydroxide. When the initiator is ethylene glycol or water the polymer is linear. With a multifunctional initiator like glycerine, pentaerythritol or sorbitol the polymer branches out.
PPG 4000
Conventional polymerization of propylene oxide results in an atactic polymer. The isotactic polymer can be produced from optically active propylene oxide, but at a high cost. A salen cobalt catalyst was reported in 2005 to provide isotactic polymerization of the prochiral propylene oxide[2]

Cobalt catalyst for isotactic polypropylene oxide
Properties
PPG 4000 has many properties in common with polyethylene glycol. The polymer is a liquid at room temperature. Solubility in water decreases rapidly with increasing molar mass. Secondary hydroxyl groups in PPG 4000 are less reactive than primary hydroxyl groups in polyethylene glycol. PPG 4000 is less toxic than PEG, so biotechnologicals are now produced in PPG 4000.

PPG 4000 (IUPAC name: propane-1,2-diol) is a viscous, colorless liquid, which is nearly odorless but possesses a faintly sweet taste. Its chemical formula is CH3CH(OH)CH2OH. Containing two alcohol groups, it is classed as a diol. It is miscible with a broad range of solvents, including water, acetone, and chloroform. In general, glycols are non-irritating and have very low volatility.
It is produced on a large scale primarily for the production of polymers. In the European Union, it has E-number E1520 for food applications. For cosmetics and pharmacology, the number is E490. PPG 4000 is also present in PPG 4000 alginate, which is known as E405. PPG 4000 is a compound which is GRAS (generally recognized as safe) by the US FDA (Food and Drug Administration) under 21 CFR x184.1666, and is also approved by the FDA for certain uses as an indirect food additive. PPG 4000 is approved and used as a vehicle for topical, oral, and some intravenous pharmaceutical preparations in the U.S. and in Europe.

Structure
The compound is sometimes called (alpha) α-PPG 4000 to distinguish it from the isomer propane-1,3-diol, known as (beta) β-PPG 4000. PPG 4000 is chiral. Commercial processes typically use the racemate. The S-isomer is produced by biotechnological routes.

Production Industrial
Industrially, PPG 4000 is mainly produced from propylene oxide (for food-grade use). According to a 2018 source, 2.16 M tonnes are produced annually.[4] Manufacturers use either non-catalytic high-temperature process at 200 °C (392 °F) to 220 °C (428 °F), or a catalytic method, which proceeds at 150 °C (302 °F) to 180 °C (356 °F) in the presence of ion exchange resin or a small amount of sulfuric acid or alkali.
Final products contain 20% PPG 4000, 1.5% of diPPG 4000, and small amounts of other polyPPG 4000s.[6] Further purification produces finished industrial grade or USP/JP/EP/BP grade PPG 4000 that is typically 99.5% or greater. Use of USP (US Pharmacopoeia) PPG 4000 can reduce the risk of Abbreviated New Drug Application (ANDA) rejection.[7]
PPG 4000 can also be obtained from glycerol, a byproduct from the production of biodiesel.[4] This starting material is usually reserved for industrial use because of the noticeable odor and taste that accompanies the final product.

Safety in humans
When used in average quantities, PPG 4000 has no measurable effect on development and/or reproduction on animals and probably does not adversely affect human development or reproduction.[26] The safety of electronic cigarettes—which utilize PPG 4000-based preparations of nicotine or THC and other cannabinoids—is the subject of much controversy.-

Oral administration
The acute oral toxicity of PPG 4000 is very low, and large quantities are required to cause perceptible health effects in humans; in fact, PPG 4000 is three times less toxic than ethanol.[30] PPG 4000 is metabolized in the human body into pyruvic acid (a normal part of the glucose-metabolism process, readily converted to energy), acetic acid (handled by ethanol-metabolism), lactic acid (a normal acid generally abundant during digestion),[31] and propionaldehyde (a potentially hazardous substance). According to the Dow Chemical Company, The LD50 (Lethal Dose that kills in 50% of tests) for rats is 20 g/kg (rat/oral).

Toxicity generally occurs at plasma concentrations over 4 g/L, which requires extremely high intake over a relatively short period of time, or when used as a vehicle for drugs or vitamins given intravenously or orally in large bolus doses.[37] It would be nearly impossible to reach toxic levels by consuming foods or supplements, which contain at most 1 g/kg of PPG 4000, except for alcoholic beverages in the US which are allowed 5 percent = 50g/kg.[38] Cases of PPG 4000 poisoning are usually related to either inappropriate intravenous administration or accidental ingestion of large quantities by children.

The potential for long-term oral toxicity is also low. In an NTP continuous breeding study, no effects on fertility were observed in male or female mice that received PPG 4000 in drinking water at doses up to 10,100 mg/kg bw/day. No effects on fertility were seen in either the first or second generation of treated mice.[26] In a 2-year study, 12 rats were provided with feed containing as much as 5% PPG 4000, and showed no apparent ill effects.[40] Because of its low chronic oral toxicity, PPG 4000 was classified by the U. S. Food and Drug Administration as "generally recognized as safe" (GRAS) for use as a direct food additive, including frozen foods such as ice cream and frozen desserts. The GRAS designation is specific to its use in food, and does not apply to other uses.

Skin, eye and inhalation contact
PPG 4000 is essentially non-irritating to the skin.[43] Undiluted PPG 4000 is minimally irritating to the eye, producing slight transient conjunctivitis; the eye recovers after the exposure is removed. A 2018 human volunteer study found that 10 male and female subjects undergoing 4 hours exposures to concentrations of up to 442 mg/m3 and 30 minutes exposures to concentrations of up to 871 mg/m3 in combination with moderate exercise did not show pulmonary function deficits, or signs of ocular irritation, with only slight symptoms of respiratory irritation reported.[44] Inhalation of PPG 4000 vapors appears to present no significant hazard in ordinary applications.[45] Due to the lack of chronic inhalation data, it is recommended that PPG 4000 not be used in inhalation applications such as theatrical productions, or antifreeze solutions for emergency eye wash stations.[46] Recently, PPG 4000 (commonly alongside glycerol) has been included as a carrier for nicotine and other additives in e-cigarette liquids, the use of which presents a novel form of exposure. The potential hazards of chronic inhalation of PPG 4000 or the latter substance as a whole are as-yet unknown.
According to a 2010 study, the concentrations of PPG 4000Es (counted as the sum of PPG 4000 and glycol ethers) in indoor air, particularly bedroom air, has been linked to increased risk of developing numerous respiratory and immune disorders in children, including asthma, hay fever, eczema, and allergies, with increased risk ranging from 50% to 180%. This concentration has been linked to use of water-based paints and water-based system cleansers. However, the study authors write that glycol ethers and not PPG 4000 are the likely culprit.
PPG 4000 has not caused sensitization or carcinogenicity in laboratory animal studies, nor has it demonstrated genotoxic potential.

Intravenous administration
Studies with intravenously administered PPG 4000 have resulted in LD50 values in rats and rabbits of 7 mL/kg BW.[53] Ruddick (1972) also summarized intramuscular LD50 data for rat as 13-20 mL/kg BW, and 6 mL/kg BW for the rabbit. Adverse effects to intravenous administration of drugs that use PPG 4000 as an excipient have been seen in a number of people, particularly with large bolus dosages. Responses may include CNS depression, "hypotension, bradycardia, QRS and T abnormalities on the ECG, arrhythmia, cardiac arrhythmias, seizures, agitation, serum hyperosmolality, lactic acidosis, and haemolysis".[54] A high percentage (12% to 42%) of directly-injected PPG 4000 is eliminated or secreted in urine unaltered depending on dosage, with the remainder appearing in its glucuronide-form. The speed of renal filtration decreases as dosage increases,[55] which may be due to PPG 4000's mild anesthetic / CNS-depressant -properties as an alcohol.[56] In one case, intravenous administration of PPG 4000-suspended nitroglycerin to an elderly man may have induced coma and acidosis.[57] However, no confirmed lethality from PPG 4000 was reported.

Animals
PPG 4000 is an approved food additive for dog and sugar glider food under the category of animal feed and is generally recognized as safe for dogs,[58] with an LD50 of 9 mL/kg. The LD50 is higher for most laboratory animals (20 mL/kg).[59] However, it is prohibited for use in food for cats due to links to Heinz body formation and a reduced lifespan of red blood cells.[60] Heinz body formation from MPPG 4000 has not been observed in dogs, cattle, or humans.

Environmental
PPG 4000 occurs naturally, probably as the result of anaerobic catabolism of sugars in the human gut. It is degraded by vitamin B12-dependent enzymes, which convert it to propionaldehyde.[68]
PPG 4000 is expected to degrade rapidly in water from biological processes, but is not expected to be significantly influenced by hydrolysis, oxidation, volatilization, bioconcentration, or adsorption to sediment.[69] PPG 4000 is readily biodegradable under aerobic conditions in freshwater, in seawater and in soil. Therefore, PPG 4000 is considered as not persistent in the environment.
PPG 4000 exhibits a low degree of toxicity toward aquatic organisms. Several guideline studies available for freshwater fish with the lowest observed effect concentration of 96-h LC50 value of 40,613 mg/l in a study with Oncorhynchus mykiss. Similarly, the effect concentration determined in marine fish is a 96-h LC50 of >10,000 mg/l in Scophthalmus maximus.

Allergic reaction
Estimates on the prevalence of PPG 4000 allergy range from 0.8% (10% PPG 4000 in aqueous solution) to 3.5% (30% PPG 4000 in aqueous solution). The North American Contact Dermatitis Group (NACDG) data from 1996 to 2006 showed that the most common site for PPG 4000 contact dermatitis was the face (25.9%), followed by a generalized or scattered pattern (23.7%).[61] Investigators believe that the incidence of allergic contact dermatitis to PPG 4000 may be greater than 2% in patients with eczema or fungal infections, which are very common in countries with lesser sun exposure and lower-than-normal vitamin D balances. Therefore, PPG 4000 allergy is more common in those countries.
Because of its potential for allergic reactions and frequent use across a variety of topical and systemic products, PPG 4000 was named the American Contact Dermatitis Society's Allergen of the Year for 2018.[65][66] Recent publication from The Mayo Clinic reported 0.85% incidence of positive patch tests to PPG 4000 (100/11,738 patients) with an overall irritant rate of 0.35% (41/11,738 patients) during a 20-year period of 1997–2016.[67] 87% of the reactions were classified as weak and 9% as strong. The positive reaction rates were 0%, 0.26%, and 1.86% for 5%, 10%, and 20% PPG 4000 respectively, increasing with each concentration increase. The irritant reaction rates were 0.95%, 0.24%, and 0.5% for 5%, 10%, and 20% PPG 4000, respectively. PPG 4000 skin sensitization occurred in patients sensitive to a number of other concomitant positive allergens, most common of which were: Myroxylon pereirae resin, benzalkonium chloride, carba mix, potassium dichromate, neomycin sulfate; for positive PPG 4000 reactions, the overall median of 5 and mean of 5.6 concomitant positive allergens was reported.

For PPG 4000 (USEPA/OPP Pesticide Code: 068602) there are 0 labels match. /SRP: Not registered for current use in the U.S., but approved pesticide uses may change periodically and so federal, state and local authorities must be consulted for currently approved uses.
Of all polyether polyols (incl PPG 4000, polyethylene glycol, and propylene oxide-ethylene oxide copolymers), 65% were used in polyurethane flexible foam; 9% in polyurethane rigid foam; 7% in noncellular polyurethane applications; 8% for surface-active agents; 8% for lubricants and functional fluids; & 3% for misc applications.

There are 2 active ingredients in reregistration case 3123 for PPG 4000. The RED evaluates the only active ingredient in this case with currently registered products; therefore, only butoxyPPG 4000 (BPG), PC Code 011901/CAS No. 9003-13-8, 57 active products as of September, 2001/ was assessed. The other active ingredient in this case /poly(oxy(methyl-1,2ethanediyl)), alpha-hydro-omegahydroxy,CAS No. 25322-69-4 / has no product registrations /last pesticide product cancelled October 10, 1989/ and is not being supported for reregistration. This active ingredient would be evaluated only if and when new registration applications were to be submitted for new products.
Method for determination of PPG 4000 at sub-ppm levels in aqueous and organic media by gas-liquid chromatography or by gas chromatography-mass spectroscopy.

PPG 4000 is an alcohol. Flammable and/or toxic gases are generated by the combination of alcohols with alkali metals, nitrides, and strong reducing agents. They react with oxoacids and carboxylic acids to form esters plus water. Oxidizing agents convert them to aldehydes or ketones. Alcohols exhibit both weak acid and weak base behavior. They may initiate the polymerization of isocyanates and epoxides.
This action promulgates standards of performance for equipment leaks of Volatile Organic Compounds (VOC) in the Synthetic Organic Chemical Manufacturing Industry (SOCMI). The intended effect of these standards is to require all newly constructed, modified, and reconstructed SOCMI process units to use the best demonstrated system of continuous emission reduction for equipment leaks of VOC, considering costs, non air quality health and environmental impact and energy requirements. PPG 4000 is produced, as an intermediate or a final product, by process units covered under this subpart.

PPG 4000 (minimum molecular weight 150) is an indirect food additive for use only as a component of adhesives.
Acute Exposure/ Propylene glycol was relatively harmless (LD50 = 21 g/kg) in acute oral toxicity studies involving rats. Acute oral toxicity studies on PPG 4000s of various molecular weights (300 to 3900 Da) have indicated LD50 values (rats) ranging from 0.5 to >40g/kg.
LABORATORY ANIMALS: Acute Exposure/ Single and repeated applications of Polypropylene glycol 425, Polypropylene glycol 1025, and Polypropylene glycol 2025 did not cause skin irritation in the rabbit. Repeated applications of Polypropylene glycol 1200 to rabbits caused mild reactions at abraded skin sites and no reactions at intact sites. Results were negative for 100% PG in a mouse external ear swelling sensitization test. The results of a guinea pig maximization, open epicutaneous, and Finn chamber tests indicated no sensitization reactions to 70%PG. In another maximization test, PG was classified as a potentially weak sensitizer. The results of six other guinea pig sensitization tests indicated that PG was not an allergen.
NIOSH (NOES Survey 1981-1983) has statistically estimated that 217,886 workers (30,699 of these were female) were potentially exposed to PPG 4000 in the US(1). Occupational exposure to PPG 4000 may occur through inhalation where mists are formed from violent agitation or high temperatures, and dermal contact with this compound at workplaces where PPG 4000 is produced or used(2).

General description of PPG 4000
PPG 4000 is an aliphatic alcohol. It is an addition polymer of PPG 4000 and water represented as H[OCH3]nOH in which n represents the average number of oxypropylene groups.

Application of PPG 4000
PPG 4000 (PPG) may be used as a viscosity decreasing agent, a solvent and a fragrance ingredient in cosmetics. PPG 4000 may be used as a good swelling agent for the synthesis of large pore mesoporous materials.

What Is It?
PPG 4000, also known as 1,2-propanediol, is a synthetic (i.e., man-made) alcohol that attracts/absorbs water. It is a viscous, colorless liquid, which is nearly odorless but possesses a faintly sweet taste. PPG 4000 is one of the most widely used ingredients in cosmetics and personal care products, including facial cleansers, moisturizers, bath soaps, shampoos and conditioners, deodorants, shaving preparations, and fragrances. In addition to its use as an ingredient in cosmetic and personal care products, it is used in numerous food items such as beer, packaged baked goods, frozen dairy products, margarine, coffee, nuts, and soda. It is also used as an inactive ingredient (e.g., solvent) in many drugs. FDA has approved its use at concentrations as high as 98% in drugs applied to the skin and 92% in drugs taken orally. 

Why is it used in cosmetics and personal care products?
Because PPG 4000 attracts water it functions as a humectant and is used in moisturizers to enhance the appearance of skin by reducing flaking and restoring suppleness. Other reported uses include skin-conditioning agent, viscosity-decreasing agent, solvent, and fragrance ingredient. 
PPG 4000 was reported to be used in 14,395 products, according to 2019 data in U.S. FDA’s Voluntary Cosmetic Registration Program (VCRP).
PPG 4000 is an alcohol. Flammable and/or toxic gases are generated by the combination of alcohols with alkali metals, nitrides, and strong reducing agents. They react with oxoacids and carboxylic acids to form esters plus water. Oxidizing agents convert them to aldehydes or ketones. Alcohols exhibit both weak acid and weak base behavior. PPG 4000 may initiate the polymerization of isocyanates and epoxides.
In dilute aqueous solution unimers of Pluronic F127 associate to form micelles. In more concentrated solution, micelles pack to form high-modulus gels. Our interest is the effect of addition of 10–30 wt % low molecular weight PPG 4000 on the micellization and gelation of solutions of F127. DLS was used to determine the apparent size of the micelles (rh,app). The critical micelle concentration (cmc) using the dye solubilization method of F127 in PPG 4000 solutions was studied. Visual observation was carried out to detect gel formation in concentrated solutions and the onset of clouding and turbidity, as the temperature was raised. Oscillatory rheometry was used to confirm the formation of high-modulus gels and provide values of elastic moduli (G′max) over a wide temperature range. SAXS was used to determine gel structure. Our results for the hydrophobic adduct PPG 4000 were compared with literature values for the hydrophilic adduct PEG6000.