2-하이드록시프로필아크릴레이트

1.06 at 77 °F (USCG, 1999) - Denser than water; will sink

1.05 kg/L at 25 °C

1.05 g/cm³

Relative density of the vapour/air-mixture at 20 °C (air = 1): 1.00

Water soluble

Miscible with water and oxygenated solvents

Solubility in water, g/100ml at 25 °C: 30.7 (good)

207 °F (NFPA, 2010)

207 °F (97 °C) (closed cup)

97 °C c.c.

Decomposes at one atmosphere

205.7 °C

Freezing point: -30 °C

-23.4 °C

4.5 (Air = 1)

Relative vapor density (air = 1): 4.5

Danger

H301: Toxic if swallowed [Danger Acute toxicity, oral]

P260, P261, P262, P264, P270, P271, P272, P280, P301+P316, P301+P330+P331, P302+P352, P302+P361+P354, P304+P340, P305+P354+P338, P316, P321, P330, P333+P317, P361+P364, P362+P364, P363, P403+P233, P405, and P501 (click each P-code to see the statement)

This chemical does not meet GHS hazard criteria for 0.1% (1 of 800) of reports.

Danger

H301 (95.9%): Toxic if swallowed [Danger Acute toxicity, oral]

Chemical: 2-Propenoic acid, monoester with 1,2-propanediol

2-Propenoic acid, monoester with 1,2-propanediol is listed on the EPA's Chemical Data Reporting (CDR) system. Manufacturers and importers of 2-Propenoic acid, monoester with 1,2-propanediol are required to report information about their production and use of this chemical to the EPA under the Toxic Substances Control Act (TSCA). (40 eCFR Part 711)

REACH registered substance: Acrylic acid, monoester with propane-1,2-diol (EC: 247-118-0)

Propylene glycol monoacrylate: Does not have an individual approval but may be used under an appropriate group standard

Excerpt from ERG Guide 154 [Substances - Toxic and/or Corrosive (Non-Combustible)]:

Combustible. Gives off irritating or toxic fumes (or gases) in a fire. Above 97 °C explosive vapour/air mixtures may be formed.

Inhalation irritates nose and throat and causes coughing; lung injury may occur. Ingestion causes irritation and burning of mouth and stomach. Vapor irritates eyes. Contact with liquid causes severe burns of eyes and burns of skin. (USCG, 1999)

Organization for Economic Cooperation and Development; Screening Information Data Set for Hydroxypropyl Acrylate, CAS No. 25584-83-2 (December 2005). This OECD Initial Assessment of HPV Chemicals is part of a series of OECD SIDS documents published by UNEP Chemicals to facilitate the access to information needed for health and environmental risk assessments of chemicals.

Health Council of the Netherlands: Hydroxypropyl acrylate (all isomers) (CAS No: 25584-83-2) Health-based Reassessment of Administrative Occupational Exposure Limits (October, 2005).[Available from, as of June 7, 2018: https://www.gezondheidsraad.nl/sites/default/files/0015osh151.pdf]

The substance may polymerize due to heating and under the influence of light, and peroxides. Decomposes on heating. This produces toxic and corrosive fumes including acrolein. Reacts violently with strong acids, strong bases, strong oxidants and peroxides. This generates fire hazard.

Excerpt from ERG Guide 154 [Substances - Toxic and/or Corrosive (Non-Combustible)]:

Use water spray, dry powder, alcohol-resistant foam, carbon dioxide. In case of fire: keep drums, etc., cool by spraying with water.

Fresh air, rest. Refer for medical attention.

Remove contaminated clothes. Rinse skin with plenty of water or shower. Refer for medical attention .

Rinse with plenty of water (remove contact lenses if easily possible). Refer for medical attention.

Rinse mouth. Do NOT induce vomiting. Refer for medical attention .

Alcohol foam.

If material on fire or involved in fire: Use water in flooding quantities as fog. Solid stream of water may be ineffective. Cool all affected containers with flooding quantities of water. Apply water from as far a distance as possible. Use "alcohol" foam, dry chemical or carbon dioxide. Use water spray to knock-down vapors.

Suitable extinguishing media: Use water spray, alcohol-resistant foam, dry chemical or carbon dioxide. Advice for firefighters: Wear self-contained breathing apparatus for firefighting if necessary.

Keep container tightly closed in a dry and well-ventilated place. Containers which are opened must be carefully resealed and kept upright to prevent leakage. Storage class (TRGS 510): Non-combustible, acute toxic Cat.3 / toxic hazardous materials or hazardous materials causing chronic effects.

The effectiveness of phenolic inhibitors is dependent on the presence of oxygen and the monomers must be stored under air rather than an inert atmosphere. Temp must be kept low to minimize formation of peroxides and other products ... The acrylic esters may be stored in mild or stainless steel, or aluminum. /Acrylic acid & derivatives/

ACCIDENTAL RELEASE MEASURES; Personal precautions, protective equipment and emergency procedures: Wear respiratory protection. Avoid breathing vapors, mist or gas. Ensure adequate ventilation. Evacuate personnel to safe areas. Environmental precautions: Prevent further leakage or spillage if safe to do so. Do not let product enter drains. Methods and materials for containment and cleaning up: Soak up with inert absorbent material and dispose of as hazardous waste. Keep in suitable, closed containers for disposal.

SRP: Wastewater from contaminant suppression, cleaning of protective clothing/equipment, or contaminated sites should be contained and evaluated for subject chemical or decomposition product concentrations. Concentrations shall be lower than applicable environmental discharge or disposal criteria. Alternatively, pretreatment and/or discharge to a permitted wastewater treatment facility is acceptable only after review by the governing authority and assurance that "pass through" violations will not occur. Due consideration shall be given to remediation worker exposure (inhalation, dermal and ingestion) as well as fate during treatment, transfer and disposal. If it is not practicable to manage the chemical in this fashion, it must be evaluated in accordance with EPA 40 CFR Part 261, specifically Subpart B, in order to determine the appropriate local, state and federal requirements for disposal.

SRP: Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air quality; potential migration in air, soil or water; effects on animal, aquatic and plant life; and conformance with environmental and public health regulations. If it is possible or reasonable use an alternative chemical product with less inherent propensity for occupational harm/injury/toxicity or environmental contamination.

Product: Offer surplus and non-recyclable solutions to a licensed disposal company. Contact a licensed professional waste disposal service to dispose of this material. Dissolve or mix the material with a combustible solvent and burn in a chemical incinerator equipped with an afterburner and scrubber. Contaminated packaging: Dispose of as unused product.

Personal protection: chemical protection suit and filter respirator for organic gases and vapours adapted to the airborne concentration of the substance. Do NOT let this chemical enter the environment. Collect leaking liquid in covered containers. Absorb remaining liquid in sand or inert absorbent. Then store and dispose of according to local regulations.

Gloves must be inspected prior to use. Use proper glove removal technique (without touching glove's outer surface) to avoid skin contact with this product. Dispose of contaminated gloves after use in accordance with applicable laws and good laboratory practices. Wash and dry hands.

Avoid contact with skin, eyes and clothing. Wash hands before breaks and immediately after handling the product.

Avoid contact with skin and eyes. Avoid inhalation of vapor or mist.

ACCIDENTAL RELEASE MEASURES; Personal precautions, protective equipment and emergency procedures: Wear respiratory protection. Avoid breathing vapors, mist or gas. Ensure adequate ventilation. Evacuate personnel to safe areas. Environmental precautions: Prevent further leakage or spillage if safe to do so. Do not let product enter drains.

For more Preventive Measures (Complete) data for Hydroxypropyl acrylate (6 total), please visit the HSDB record page.

LC50; Species: Pimephales promelas (fathead minnow) 34 day old; Conditions: flow through, water hardness 45.4 mg/L (CaCO3), temp 24.4 °C, pH 7.55, dissolved oxygen 6.4 mg/L, alkalinity 49.3 mg/L (CaCO3), tank vol 2.0 L, additions 18 vol/day; Concentration: 3.61 mg/L for 96 hr />97% purity/

EC50; Species: Pimephales promelas (fathead minnow) 34 day old; Conditions: flow through, water hardness 45.4 mg/L (CaCO3), temp 24.4 °C, pH 7.55, dissolved oxygen 6.4 mg/L, alkalinity 49.3 mg/L (CaCO3), tank vol 2.0 L, additions 18 vol/day; Concentration: 3.61 mg/L for 96 hr; Effect: Affected fish lost schooling behavior and swam near the tank surface in a corkscrew/spiral pattern. They were hyperactive, had increased respiration, were darkly colored and deformed, had edema, and lost equilibrium prior to death. />97% purity/

LC50; Species: Pimephales promelas (fathead minnow) 33 day old; Conditions: flow through, water hardness 45.9 mg/L (CaCO3), temp 24.7 °C, pH 7.87, dissolved oxygen 6.7 mg/L, alkalinity 45.0 mg/L (CaCO3), tank vol 2.0 L, additions 18 vol/day; Concentration: 3.1 mg/L for 96 hr />97% purity/

EC50; Species: Pimephales promelas (fathead minnow) 33 day old; Conditions: flow through, water hardness 45.9 mg/L (CaCO3), temp 24.7 °C, pH 7.87, dissolved oxygen 6.7 mg/L, alkalinity 45.0 mg/L (CaCO3), tank vol 2.0 L, additions 18 vol/day; Concentration: 1.9 mg/L for 96 hr; Effect: Affected fish lost schooling behavior and swam near the tank surface in a corkscrew/spiral pattern. They were hyperactive and overreactive to external stimuli, had increased respiration and rigid musculature, showed signs of edema, were deformed, and lost equilibrium prior to death. />97% purity/

For more Ecotoxicity Values (Complete) data for Hydroxypropyl acrylate (7 total), please visit the HSDB record page.

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 1.5(SRC), determined from a structure estimation method(2), indicates that hydroxypropyl acrylate is expected to have very high mobility in soil(SRC). Volatilization of hydroxyporpyl acrylate from moist soil surfaces is not expected to be an important fate process(SRC) given an estimated Henry's Law constant of 1.7X10-9 atm-cu m/mole(SRC), developed using a fragment constant estimation method(2). Hydroxypropyl acrylate is not expected to volatilize from dry soil surfaces(SRC) based upon an estimated vapor pressure of 0.12 mm Hg at 25 °C(SRC), determined from a fragment constant method(2). A 83% of Theoretical BOD using activated sludge in the Japanese MITI test(3) suggests that biodegradation is an important environmental fate process in soil(SRC). Using an ecosystem model, degradation rate of hydroxypropyl acrylate in soil was 3.4X10-7/s(4).

AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 1.5(SRC), determined from a structure estimation method(2), indicates that hydroxypropyl acrylate 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 1.7X10-9 atm-cu m/mole(SRC), developed using a fragment constant estimation method(2). A base-catalyzed second-order hydrolysis rate constant of 0.018 L/mole-sec(SRC) was estimated using a structure estimation method(2); this corresponds to half-lives of 12 and 1.2 years at pH values of 7 and 8, respectively(2). According to a classification scheme(4), an estimated BCF of 3(SRC), from an estimated log Kow of 0.17(2) and a regression-derived equation(2), suggests the potential for bioconcentration in aquatic organisms is low. A 83% of Theoretical BOD using activated sludge in the Japanese MITI test(5) suggests that biodegradation may be an important environmental fate process in water(SRC). Using an ecosystem model, degradation rates of hydroxypropyl acrylate in water and sediment were 6.8X10-7/s and 7.5X10-8/s, respectively(6).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), hydroxypropyl acrylate, which has an estimated vapor pressure of 0.12 mm Hg at 25 °C(SRC), determined from a fragment constant method(2), is expected to exist solely as a vapor. Vapor-phase hydroxypropyl acrylate is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals and ozone(SRC); the half-lives for these reactions in air is estimated to be 22 hours and 6.5 days(SRC), calculated from its respective rate constants of 1.7X10-11 and 1.7X10-18 cu cm/molecule-sec at 25 °C(SRC) that were derived using a structure estimation method(2). Hydroxypropyl acrylate contains chromophores that absorb at wavelengths >290 nm(3) and, therefore, may be susceptible to direct photolysis by sunlight(SRC). The degradation rate of hydroxypropyl acrylate in air was 1.4X10-5/s based on calculations using a chemical pollution footprint methodology(4).

IDENTIFICATION AND USE: Hydroxypropyl acrylate is a colorless liquid. It is mainly used either as a co-monomer in the manufacture of polymers or as a chemical reactant in the manufacture of chemical intermediates. It is used in food contact substances as indirect additive. HUMAN STUDIES: In human patch tests, three out of 24 patients showing irritation to initial exposure to acrylates including hydroxypropyl acrylate, showed sensitization reactions to hydroxypropyl acrylate exposure. Several cases of occupational contact dermatitis have been reported. ANIMAL STUDIES: In experimental animals, hydroxypropyl acrylates were highly irritating and corrosive to the eyes. Applied to the skin, they caused marked irritation and, occasionally, necrosis. Contact sensitivity was produced in guinea pigs. In rats given up to 2000 mg/kg clinical signs included ataxia, salivation, and passiveness. Animals that died during the study showed stained muzzle, lungs, stomach and intestines red and fluid filled, and enlarged stomach. An inhalation study with rats, mice, rabbits and dogs was conducted with hydroxypropyl acrylate. In rats, a small increase in the number of animals with changes in the lungs at 10 ppm (subacute pneumonitis) and the nasal mucosa was observed. In the mouse study, no mortality was observed. Three of 20 mice exposed to 10 ppm, but none exposed to 5 ppm showed signs of eye irritation. All rabbits exposed to 10 ppm and 2 of 4 animals exposed to 5 ppm developed slight rhinitis and eye irritation (moderate conjunctivitis). The most marked effects were seen in the upper respiratory system of all rabbits, especially those in the 10 ppm group that were characterized by mucopurulent rhinitis with squamous metaplasia and ulceration of the nasal turbinate mucosa. In the dog study, no mortality was observed. At necropsy, exudative rhinitis, tracheitis, and suppurative bronchopneumonia were observed in all hydroxypropyl acrylate-exposed dogs. Therefore, conjunctivitis and inflammatory, degenerative, and/or hyperplastic changes in the (upper) respiratory tract are the key effects following exposure to a mixture of hydroxypropyl acrylate isomers after inhalation exposure. No evidence of carcinogenicity was observed for the closely related, hydroxyethyl acrylate, following 18 months of inhalation exposure. In developmental study in rats exposed by inhalation (1, 5, or 10 ppm) no treatment related increase in embryo/fetal lethality or fetal malformations was observed at any dose level. Hydroxypropyl acrylate was tested in the bacterial reverse mutation assay test with Salmonella typhimurium TA98, TA100, TA1535, and TA1537 at concentrations up to 5000 ug/plate with and without metabolic activation. It was considered not mutagenic under the conditions of the assay .

Cough. Sore throat. Burning sensation.

MAY BE ABSORBED! Redness. Pain.

Redness. Pain.

Abdominal pain. Burning sensation in the throat and chest. Vomiting.

EPA has released the Interactive Chemical Safety for Sustainability (iCSS) Dashboard. The iCSS Dashboard provides an interactive tool to explore rapid, automated (or in vitro high-throughput) chemical screening data generated by the Toxicity Forecaster (ToxCast) project and the federal Toxicity Testing in the 21st century (Tox21) collaboration. /The title compound was tested by ToxCast and/or Tox21 assays/[USEPA; ICSS Dashboard Application; Available from, as of August 9, 2018: http://actor.epa.gov/dashboard/]

Using a structure estimation method based on molecular connectivity indices(1), the Koc of hydroxypropyl acrylate can be estimated to be 1.5(SRC). According to a classification scheme(2), this estimated Koc value suggests that hydroxypropyl acrylate is expected to have very high mobility in soil(SRC).

/HUMAN EXPOSURE STUDIES/ In human patch tests, three out of 24 patients showing irritation to initial exposure to acrylates including hydroxypropyl acrylate, showed sensitization reactions to hydroxypropyl acrylate exposure.

/HUMAN EXPOSURE STUDIES/ Data on allergic contact dermatitis from acrylates and 4 patients sensitized during routine patch testing are reported. During 1982-1985, 7 different acrylates /were used/ for tests. 1 patient out of 22 (= 4.5%) was sensitized to ethyl acrylate and butyl acrylate (1% pet.). Since September 1985, ... a commercial (meth)acrylate series containing 28 substances /was used/. 3 of 24 patients tested became sensitized to ethyl acrylate, 2-hydroxyethyl acrylate and 2-hydroxypropyl acrylate (0.5% pet.). Because active sensitization with acrylates can be very harmful, it may be necessary to use lower concentrations than recommended. Currently, ethyl acrylate, 2-hydroxyethyl acrylate and 2-hydroxypropyl acrylate at 0.167% pet. /are tested by the authors/.

/CASE REPORTS/ A case of contact dermatitis and allergenicity from exposure to hydroxypropyl-acrylate (HPA) was described. A 39 year old male who worked as a maintenance fitter at a facility that manufactured HPA and methacrylate esters developed swelling and blisters on the right foot 12 hours after he cleaned a backset strainer containing HPA polymer. Six months later an erythematous papular eruption developed on his forearms, thighs, and groin after he worked on the HPA system for 1 day. The lesions cleared up after a few days. The lesions reappeared after the patient returned to work even though there was no further known exposure to HPA. The patient, however, had worn boots that may have been contaminated with HPA. Patch testing with HPA, hydroxypropyl-methacrylate, and hydroxyethyl-methacrylate yielded positive results. The patient avoided further exposure to HPA and the dermatitis subsequently cleared. It was suggested that the patient was sensitized to HPA and developed a cross sensitivity to methacrylates to which he had been exposed previously at the facility.

/EPIDEMIOLOGY STUDIES/ A number of case reports ... are presented for exposure to hydroxypropyl acrylate. These reports suggest that hydroxypropyl acrylate is likely to cause sensitization and cross-react with other acrylates in some exposed individuals. The human exposure to hydroxypropyl acrylate, however, is extremely limited since the only potential for repeated exposure is in workplace environments that have stringent protective procedures to avoid contact with the highly irritating chemical.

/OTHER TOXICITY INFORMATION/ Data on effects of exposure to hydroxypropyl acrylates are limited to cases of allergenic effects...

An estimated BCF of 3 was calculated in fish for hydroxypropyl acrylate(SRC), using an estimated log Kow of 0.17(1) and a regression-derived equation(1). According to a classification scheme(2), this BCF suggests the potential for bioconcentration in aquatic organisms is low.

2-hydroxyethyl acrylate (HEA) has been evaluated in a study that examined metabolism and excretion in male Fischer 344 rat using oral, intraperitoneal, dermal and inhalation routes of exposure ... For the oral and intraperitoneal routes of exposure the rats (four animals/dose level/route of exposure) received a single dose of (14)C-HEA at 2.5 or 50 mg/kg bw. For the inhalation exposure, six rats were exposed to a target concentration of 8 ppm (14)C-HEA for six hours in a head only inhalation chamber. For the dermal exposure, four rats were treated with (14)C-HEA at a dose of 50 mg/kg. No qualitative differences in urinary metabolites between routes were observed, indicating no marked route-dependent differences in the metabolic fate of HEA. The results of the study indicate that once the chemical becomes systemically available it is rapidly metabolized and eliminated from the body as either CO2 in the expired air or urinary metabolites with approximately equal percentage of administered/exposed dose eliminated by each route. The half-lives of elimination of radioactivity were approximately 14 hours for urine and 17 hours for CO2. The half-life of elimination of radioactivity from plasma was approximately 26 hours although the label was not associated with parent HEA. The available metabolic data on HEA is consistent with information on studies with other acrylates where hydrolysis of the ester functionality is the primary metabolic pathway. By analogy with ethyl acrylate and acrylic acid, it is expected that a minor metabolic pathway for HEA will be via conjugation with glutathione with the resulting mercapturic acid derivatives being excreted in the urine.

Comonomer in adhesives, elastomers, inks, and oil additives; viscosity reducer.

Hydroxypropyl acrylate is mainly used either as a co-monomer in the manufacture of polymers or as a chemical reactant in the manufacture of chemical intermediates.

For the manufacture of hydrogel contact lenses. /3-Hydroxypropyl acrylate/

Indirect Additives used in Food Contact Substances: HYDROXYPROPYL ACRYLATE

Hydroxypropyl acrylates, usually as isomer mixtures, are used in the industrial production of acrylate polymers for lacquers and artificial resins, and as a co-monomer in adhesives, elastomers, inks, and oil additives and as a viscosity reducer.

Contains the following stabilizer(s): Mequinol (200 ppm)

A typical commercial sample of hydroxypropyl acrylate may contain acrylic acid (< or = 0.98% w/w), other esters (< or = 1.8% w/w), propylene glycol diacrylate (< or = 0.2% w/w) and propylene oxide (ca. 0.001% w/w). Methyl ethyl hydroquinone may be added at 250 to 650 ppm as an inhibitor of spontaneous polymerization.

2023: 1,000,000 - <5,000,000 lb

(1972) 4.5X10+9 g (Capacity includes Hydroxyethyl)

(1975) 4.5X10+9 g (Capacity includes Hydroxyethyl)

The worldwide production volume of hydroxypropyl acrylate is estimated to be 6000 to 7000 tons per year. The US production is estimated to be 5000 tons per year.

2-Propenoic acid, monoester with 1,2-propanediol is listed as a High Production Volume (HPV) chemical (65FR81686). Chemicals listed as HPV were produced in or imported into the U.S. in >1 million pounds in 1990 and/or 1994. The HPV list is based on the 1990 Inventory Update Rule. (IUR) (40 CFR part 710 subpart B; 51FR21438).

For more U.S. Production (Complete) data for Hydroxypropyl acrylate (7 total), please visit the HSDB record page.

US consumption of commodity acrylate esters (2000): surface coatings 44%, adhesives/sealants 18%, textiles 15%, plastics additives 9%, paper 5%, other 9%; Western European consumption of commodity acrylate esters (1984): surface coatings 35-40%, adhesives/sealants 15%, textiles 10-15%, paper coating 15-20%, fibers and plastic comonomers 10%, other 10%

Essentially 100% as monomer.

Reaction of acrylic acid and propylene oxide, catalyzed by a base

Acrylate esters can be made by reacting a vinyl halide with carbon monoxide and an organic halide in the presence of a Group VIII catalyst. Also developed is a process that yields acrylate esters after the generation of 2-halo-1-alkenes from hydrocarbon streams. Both processes were developed by Dow Chemical Co.

In ... propylene oxidation process acrolein is first formed by the catalytic oxidation of propylene vapor at high temp in the presence of steam. The acrolein is then oxidized to acrylic acid ... The acrylic acid is esterified with alcohol to the ... acrylic ester in a separate process. /Acrylic ester monomers/

Hydroxypropyl acrylate is mainly used either as a co-monomer in the manufacture of polymers or as a chemical reactant in the manufacture of chemical intermediates.

This CAS RN represents the commercial product as routinely produced that contains approximately 75-80% 2-hydroxypropyl acrylate (CAS No 999-61-1) and 20-25% 1-methyl-2-hydroxyethyl acrylate (CAS No 2918-23-2)

Plastics Material and Resin Manufacturing

2-Propenoic acid, monoester with 1,2-propanediol: ACTIVE

Cosmetics with improved moisture-holding & softening properties contain crosslinked acid -2,3-dihydroxypropyl acrylate copolymer &/or crosslinked acrylic acid-2-hydroxypropyl acrylate copolymer. Thus, a hand cream contained glycerol 12.0, purified water 69.3, crosslinked acrylic acid-2,3-dihydropropyl acrylate copolymer (esterification = 5%) 0.1, triethanolamine 0.1, colors 0.5, cetyl alcohol 100, lanolin 6.0, & mineral spirit 2.0 wt % & perfumes.

Terpolymers for use as film- forming cmpd & coatings in cosmetics & pharmaceuticals contain: vinylpyrrolidine 10-40, vinyl acetate or vinyl propionate 20-50, & hydroxyethyl acrylate or methacrylate or hydroxypropyl acrylate 10-40% by wt. The polymers are especially useful as tablet binders & coatings in hair sprays & setting lotions. ...

A typical commercial sample of hydroxypropyl acrylate contains approximately 75-80% 2-hydroxypropyl acrylate and 20-25% 1-methyl-2- hydroxyethyl acrylate. The purity of the salable product is at least 97% combined isomers.