HuagongsheHuagongshe Chemistry Print Report · For research reference only
Boric Acid
BORATE BUFFER · Orthoboric acid · boric · Boric acid flakes · pengsuan · TBE BUFFER · Boricacid,99.8% · Boric acid (H3BO3)
Identifiers & Physical Properties
| CAS No. | 10043-35-3 |
|---|---|
| Molecular formula | BH3O3 |
| Average molar mass | 61.84 g/mol |
| Monoisotopic mass | 62.01752436 g/mol |
| SMILES | OB(O)O |
| InChIKey | KGBXLFKZBHKPEV-UHFFFAOYSA-N |
| PubChem CID | 7628 |
| ChEMBL | CHEMBL42403 |
| ChEBI | CHEBI:33118 |
| EC No. | 233-139-2 |
| DTXSID | DTXSID1020194 |
Chemical & Physical Properties
| Topological polar surface area | 60.7 |
|---|---|
| Hydrogen bond donors | 3 |
| Hydrogen bond acceptors | 3 |
| Rotatable bonds | 0 |
| Heavy atoms | 4 |
| Formal charge | 0 |
| Complexity | 8 |
| Chemical classes | Metals -> Metalloid Compounds (Boron) |
| Cosmetics | Cosmetic ingredients (Boric Acid) -> CIR (Cosmetic Ingredient Review)Antimicrobial |
| pH | 3,8-4,8 (3,3 % aqueous solution)pH = 5.1 (0.1 Molar)3.6-4.4 (25℃, saturated solution in H2O) |
| Pesticides | InsecticidesActive substance -> EU Pesticides database: Not approved |
| LogP (partition coefficient) | log Kow = 0.1750.18-1.09 |
| Odor | Odorless |
| Taste | Faintly bitter |
| Food additives | LUBRICANT OR RELEASE AGENT -> FDA Substance added to food |
| Density | 1.435 at 68 °F (USCG, 1999) - Denser than waterwill sink1.5 g/cu cmRelative density (water = 1): 1.51.435 @25 °C1.440 g/cm3 |
| Color/Form | Colorless, transparent crystals or white granules or powderColorless triclinic crystalsWhite waxy triclinic solid plates |
| Solubility | 10 to 50 mg/mL at 66 °F (NTP, 1992)Soluble in hot water, partially soluble in cold waterSlightly unctuous to touchvolatile with steamsolubility in water increased by hydrochloric, citric or tartaric acidsSolubility: in glycerol 17.5% at 25 °Cethylene glycol 18.5% at 25 °Cin methanol 173.9 g/L at 25 °Cin ethanol 94.4 g/L at 25 °Cin acetone 0.6% at 25 °Cethyl acetate 1.5% at 25 °CWater solubility: 2.52% at 0 °C3.49% at 10 °C4.72% at 20 °C6.23% at 30 °C8.08% at 40 °C10.27% at 50 °C12.97% at 60 °C15.75% at 70 °C19.10% at 80 °C23.27% at 90 °C27.53% at 100 °CSolubility in water is increased by hydrochloric acidH2O: soluble49.5 g/L (20 ºC) |
| Animal Drugs | Pharmaceuticals -> UK Veterinary Medicines Directorate List |
| Melting point | 160 °C (dec.) (lit.) |
| Boiling point | 219-220 °C (9.7513 mmHg) |
| Bulk density | 400-600kg/m3 |
| Vapor pressure | 2.6 mm Hg ( 20 °C) |
| Refractive index | n20/D 1.330-1.340 |
| Storage conditions | Store at +5°C to +30°C. |
| Physical state | working solution |
| pKa (acidity coefficient) | 8.91±0.43(Predicted) |
| Specific gravity | 1.435 |
| Color | ≤10(APHA) |
| PH Range | 3.8 - 4.8 |
| Specific heat capacity | Cp(crystal): 1.39 J/(g·K), at 25℃ |
| Sensitivity | Hygroscopic |
| λmax | λ: 260 nm Amax: 0.05λ: 280 nm Amax: 0.05 |
| Merck | 14,1336 |
| BRN | 1697939 |
| Henry's law constant | 3.8×106 mol/(m3Pa) at 25℃, HSDB (2015) |
| Exposure limits | ACGIH: TWA 2 mg/m3STEL 6 mg/m3 |
| Cosmetics Ingredients Functions | BUFFERINGDENATURANTANTIMICROBIAL |
| Cosmetic Ingredient Review (CIR) | Boric acid (10043-35-3) |
| InChI | 1S/BH3O3/c2-1(3)4/h2-4H |
| InChIKey | KGBXLFKZBHKPEV-UHFFFAOYSA-N |
| SMILES | OB(O)O |
| LogP (partition coefficient) | -1.09 at 22℃ |
| Toxicology and Carcinogenesis | Toxicology and Carcinogenesis Studies of Boric Acid (CASRN 10043-35-3) in B6C3F1 Mice (Feed Studies) |
| Substances of Very High Concern (SVHC) Candidate List | Boric acid (10043-35-3) |
| Substances Added to Food (formerly EAFUS) | BORIC ACID |
| FDA 21 CFR | 175.105176.180178.2010181.30 |
| CAS DataBase Reference | 10043-35-3(CAS DataBase Reference) |
| FDA UNII | R57ZHV85D4 |
| NIST Chemistry Reference | B(OH)3(10043-35-3) |
| EPA Substance Registry System | Orthoboric acid (10043-35-3) |
| Absorption | ≤0.05 at 260 in H2O at 1M≤0.05 at 280 in H2O at 1M |
| UNSPSC Code | 41116116 |
| NACRES | NB.21 |
| GHS pictogram | GHS08 |
| Signal word | Danger |
| GHS hazard statements | H360FD |
| GHS precautionary statements | P201-P202-P280-P308+P313-P405-P501 |
| Hazard symbols | Xi,T,Xn |
| Risk statements (R) | 36/37/38-60-63-62-61 |
| Safety statements (S) | 26-36-53-45-37/39-36/37/39-22-24/25-23 |
| Water hazard class (WGK) | 2 |
| RTECS number | ED4550000 |
| F | 3 |
| TSCA inventory status | TSCA listed |
| Customs code | 28100090 |
| Storage class | 6.1C - Combustible acute toxic Cat.3toxic compounds or compounds which causing chronic effects |
| Hazard class | Repr. 1B |
| Hazardous substances data | 10043-35-3(Hazardous Substances Data) |
| Toxicity | LD50 orally in rats: 5.14 g/kg (Smyth). |
| REACH registrations | Active |
Safety & Regulations
| GHS classification | DangerH360FD: May damage fertilityMay damage the unborn child [Danger Reproductive toxicity]P203, P280, P318, P405, and P501 (click each P-code to see the statement) |
|---|---|
| Regulatory information | Chemical: Boric acid (H3BO3)Chemical: Boric acidHazard Traits - Reproductive ToxicityRegulation (EC) No 257/2010Boric acid (H3BO3) is listed on the EPA's Chemical Data Reporting (CDR) system. Manufacturers and importers of Boric acid (H3BO3) 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)2004/129/EC |
| Other safety information | IMAP assessments - Boric acid and precursors to boric acid: Environment tier II assessment |
| Fire hazards | Literature sources indicate that this compound is nonflammable. (NTP, 1992)Not combustible. Gives off irritating or toxic fumes (or gases) in a fire. |
| Fire potential | Not flammable |
| Health hazards | Although no adverse effects have been reported from inhaling boric acid dust, it is absorbed through mucous membranes. Ingestion of 5 grams or more may irritate gastrointestinal tract and affect central nervous system. Contact with dust or aqueous solutions may irritate eyesno chronic effects have been recognized, but continued contact should be avoided. Dust and solutions are absorbed through burns and open wounds but not through unbroken skin. (USCG, 1999) |
| Hazards summary | In typical cases of poisoning by ingestion, the victims have vomiting and diarrhea, skin desquamation, mucosal erosions, and injury to the liver and kidneysEvidence of neurotoxicity includes seizures, delirium, and coma. The mechanism of toxicity is not known. [Ford, p. 750-1] A skin irritant[Quick CPC] In high-dose reproductive studies of animals, boric acid causes testicular damage and fetal loss. [Frazier, p. 252-4] The basis for the TLV for inorganic borate compounds (including boric acid) is irritation of the nose and respiratory tract. Studies of workers exposed to sodium borate dusts found no evidence of pulmonary function or reproductive impairment. [ACGIH] A skin, eye, and respiratory tract irritantMay have effects on the GI tract, liver, and kidneysCan be absorbed through skinMay cause adverse effects to human reproduction, based on animal studies[ICSC] Not likely to pose a hazard to human reproduction, based on usual human exposures being well below the doses considered to have adverse effects on reproduction[REPROTOX] A mild skin irritantMay cause reproductive effects[Alfa Aesar MSDS] See Boron. |
| FDA requirements | Boric acid is an indirect food additive for use only as a component of adhesives.Drug products containing certain active ingredients offered over-the-counter (OTC) for certain uses. A number of active ingredients have been present in OTC drug products for various uses, as described below. However, based on evidence currently available, there are inadequate data to establish general recognition of the safety and effectiveness of these ingredients for the specified uses: boric acid is included in topical acne drug productsdandruff/seborrheic dermatitis/psoriasis drug productsskin protectant drug productsastringent drug productsfever blister and cold sore treatment drug productsinsect bite and sting drug productspoison ivy, poison oak, poison sumac drug productsophthalmic anti-infective drug productsdiaper rash drug productsand antiseptic drug products. |
| Reactive group | Acids, Weak |
| EC classification | R: 60-61S: 53-45Symbol: T |
| Special Reports | Siegel E, Wason SPediatr Clin North Am 33 (2): 363-67 (1986)USEPA/OWRSQuality Criteria for Water 1986 Boron (1986) EPA 440/5-86-001DHHS/ATSDRToxicological Profile for Boron (1992) ATSDR/TP-91/05DHHS/NTPToxicology and Carcinogenesis Studies of Boric Acid (CAS No. 10043-35-3) in B6C3F1 Mice (Feed Studies) Technical Report Series No. 324 (1987) NIH Publication No. 88-2580[Available from, as of April 4, 2003: http://ntp.niehs.nih.gov/ntp/htdocs/LT_rpts/tr324.pdf]For more Special Reports (Complete) data for BORIC ACID (7 total), please visit the HSDB record page. |
| EPA Safer Chemical | Chemical: Orthoboric acid |
| FIFRA requirements | Residues of boric acid are exempted from the requirement of a tolerance when used in accordance with good agricultural practice as inert (or occasionally active) ingredients in pesticide formulations applied to growing crops only. Use: sequestrant. Limit: none.An exemption from the requirement of a tolerance is established for residues of the pesticidal chemical boric acid and its salts, borax (sodium borate decahydrate), disodium octaborate tetrahydrate, boric oxide (boric anhydride), sodium borate and sodium metaborate, in or on raw agricultural commodities when used as an active ingredient in insecticides, herbicides, or fungicides preharvest or postharvest in accordance with good agricultural practices.Based on the reviews of the generic data for the active ingredients of boric acid and its sodium salts, the Agency has sufficient information on the health effects of boric acid and its sodium salts and their potential for causing adverse effects in fish and wildlife and the environment. Therefore, the Agency concludes that products containing boric acid and its sodium salts for all uses are eligible for reregistration. The Agency has determined that boric acid and its sodium salts, labeled and used as specified in the RED document, will not pose unreasonable risks or adverse effects to humans or the environment.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 continued use. Under this pesticide reregistration program, EPA examines newer health and safety data for pesticide active ingredients initially registered before November 1, 1984, and determines whether the use of the pesticide does not pose unreasonable risk in accordance to newer saftey standards, such as those described in the Food Quality Protection Act of 1996. Borax is found on List A, which contains most food use pesticides and consists of the 194 chemical cases (or 350 individual active ingredients) for which EPA issued registration standards prior to FIFRA '88. Case No: 0024Pesticide type: insecticide, fungicide herbicideRegistration Standard Date: 11/01/85Case Status: RED Approved 9/93OPP has made a decision that some/all uses of the pesticide are eligible for reregistration, as reflected in a Reregistration Eligibility Decision (RED) document .Active ingredient (AI): boric acidData Call-in (DCI) Date(s): 2/16/94AI Status: OPP has completed a Reregistration Eligibility Decision (RED) for the case/AI. |
| Fire fighting | Fire Extinguishing Agents: Water fog. (USCG, 1999)In case of fire in the surroundings, use appropriate extinguishing media. |
| First aid measures | Fresh air, rest.Rinse and then wash skin with water and soap.Rinse with plenty of water (remove contact lenses if easily possible).Rinse mouth. Do NOT induce vomiting. Refer immediately for medical attention. |
| First aid | EYES: First check the victim for contact lenses and remove if present. Flush victim's eyes with water or normal saline solution for 20 to 30 minutes while simultaneously calling a hospital or poison control center. Do not put any ointments, oils, or medication in the victim's eyes without specific instructions from a physician. IMMEDIATELY transport the victim after flushing eyes to a hospital even if no symptoms (such as redness or irritation) develop. |
| Safe storage | Separated from strong bases. |
| Exposure control and personal protection | 10.0 [mg/m3], inhalable fraction[German Research Foundation (DFG)] |
| Storage conditions | Preserve in well-closed containers. |
| Nonfire spill response | SMALL SPILLS AND LEAKAGE: If you spill this chemical, you should dampen the solid spill material with water, then transfer the dampened material to a suitable container. Use absorbent paper dampened with water to pick up any remaining material. Seal your contaminated clothing and the absorbent paper in a vapor-tight plastic bag for eventual disposal. Wash all contaminated surfaces with a strong soap and water solution. Do not reenter the contaminated area until the Safety Officer (or other responsible person) has verified that the area has been properly cleaned. |
| Disposal methods | SRP: The most favorable course of action is to use an alternative chemical product with less inherent propensity for occupational exposure or environmental contamination. 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 qualitypotential migration in soil or watereffects on animal, aquatic, and plant lifeand conformance with environmental and public health regulations. |
| Spillage disposal | Personal protection: particulate filter respirator adapted to the airborne concentration of the substance. Sweep spilled substance into covered containers. If appropriate, moisten first to prevent dusting. Wash away remainder with plenty of water. |
| Preventive Measures | SRP: The scientific literature for the use of contact lenses by industrial workers is inconsistent. The benefits or detrimental effects of wearing contact lenses depend not only upon the substance, but also on factors including the form of the substance, characteristics and duration of the exposure, the uses of other eye protection equipment, and the hygiene of the lenses. However, there may be individual substances whose irritating or corrosive properties are such that the wearing of contact lenses would be harmful to the eye. In those specific cases, contact lenses should not be worn. In any event, the usual eye protection equipment should be worn even when contact lenses are in place.Containers of boric acid should bear an autoclavable poison label.Avoid depositing product onto exposed food and feed processing, preparation and serving surfaces, or introducing material into air. Do not apply when food processing facility is in operation. Any product visible after application must be brushed into cracks and crevices, or removed. Place product in areas that are inaccessible to children and pets. |
| Eye Prevention | Wear safety spectacles or eye protection in combination with breathing protection. |
| Inhalation Risk | Evaporation at 20 °C is negligiblea harmful concentration of airborne particles can, however, be reached quickly , especially if powdered. |
| Body burden | In serum (children): Conventional reference range: < 7 mg/Linternational recommended reference range: < 119 umol/L /From table, borate/In serum (male adult): Conventional reference range: < 2 mg/Linternational recommended reference range: < 34 umol/L /From table, borate/In serum (toxic concn): Conventional reference range: > 20 mg/Linternational recommended reference range: > 340 umol/L /From table, borate/ |
| Treatment | EYES: irrigate opened eyes for several minutes under running water. INGESTION: do not induce vomiting. Rinse mouth with water (never give anything by mouth to an unconscious person). Seek immediate medical advice. SKIN: should be treated immediately by rinsing the affected parts in cold running water for at least 15 minutes, followed by thorough washing with soap and water. If necessary, the person should shower and change contaminated clothing and shoes, and then must seek medical attention. INHALATION: supply fresh air. If required provide artificial respiration. |
| Interactions | ... Genetic effects of boric acid and borax (2.5, 5 and 10 microm) on cultures with and without TiO(2) addition. No significant increase in /sister-chromatid exchanges/ (SCE) and micronuclei frequencies were observed at all concentrations of boron compounds. However, TiO(2)-induced SCE and micronuclei could be reduced significantly by the presence of boric acid and borax. In conclusion, this study indicated for the first time that boric acid and borax led to an increased resistance of DNA to damage induced by TiO(2).Boric acid enhanced action of hypnotics, but devoid of activity itself.The usefulness of N-acetylcysteine (NAC) as a chelating agent was studied for ... boric acid. Mature Sprague-Dawley rats were intoxicatedurinary excretion rates of intoxicant and total urine volume were determined during treatment. N-acetylcysteine proved to be the most effective agent at increasing the excretion of boron and was also able to reverse the oliguria associated with this chemical.... Previous results have shown that exposure of pregnant rats on GD10 to either hyperthermia (42C) or boric acid (BA) specifically targets segmentation patterns. Exposure to hyperthermia increased the prevalence of fused and/or reduced numbers of vertebrae and ribs, primarily in the thoracic area. BA (500-1000 mg/kg, single oral dose) resulted in a significant increase in segmentation defects similar to those seen after hyperthermia, with a greater incidence in lumbar defects. In this study, we focused on the interaction of these two agents and their effects on axial skeletal development. Pregnant rats were treated on GD10 as follows: Anesthesia with Nembutal (30 mg/kg), followed by oral dosing with either water or BA (500 mg/kg) and immersion in a water bath at 37C (30 min) or 42C (rectal temp maintained at 42C for 5 min). After delivery, pups were evaluated on postnatal day (PND) 1 and 3 for number, sex, and weight. No differences were seen in litter size, pup survival, or pup weight in any of the groups. On PND3, pups were examined and processed for skeletal staining with alizarin red and alcian blue. Preliminary data indicate an increase in skeletal alterations with BA+37C (47%), water+42C (75%), or BA+42C (67%), as compared to water+37C controls (0%). Alterations included defects in ribs and vertebrae and a decrease in the number of presacral vertebrae. Because the incidence of segmentation defects in the water+42C group was high, any interaction between BA and hyperthermia might have been obscured... |
| Ecotoxicity values | LC50Species: Oncorhynchus mykiss (Rainbow trout)Concentration: 100 ppm for 96 hr (soft water)exposure was initiated subsequent to fertilization and maintained through 4 days posthatching /Conditions of bioassay not specified in source examined/Concentration: 79 ppm for 96 hr (hard water)Species: Ictalurus punctatus (Channel catfish)Concentration: 155 ppm for 96 hr (soft water)Concentration: 22 ppm for 96 hr (hard water)For more Ecotoxicity Values (Complete) data for BORIC ACID (46 total), please visit the HSDB record page. |
| Environmental fate | TERRESTRIAL FATE: The pKa of boric acid is 9.24 at 25 °C(1), indicating that this compound will exist primarily in the undissociated form at an environmental pH range between pH 5 and pH 9, although the anion form will partially exist in alkaline soils(SRC). Adsorption of boron in soils depends on pH, organic content and types of clay and minerals in the soil(1). At acidic pH, boron exists in solutions in the form of undissociated boric acidat alkaline pH, presence of borate ion occurs, which reaches maximum adsorption at pH 8.5-9(2). Field studies have observed boron to leach readily in soil(1)undissociated boric acid is transported in soil with little adsorption(2). Volatilization of boric acid from moist soil surfaces is not expected to be an important fate process(SRC) given an estimated Henry's Law constant of 2.6X10-12 atm-cu m/mole(SRC), based upon its vapor pressure, 1.6X10-6 mm Hg(3), and water solubility, 5X10+4 mg/L(4). Boric acid is not expected to volatilize from dry soil surfaces(SRC) based upon its vapor pressure. No biotransformation processes have been reported for boron compounds, including boric acid(2).AQUATIC FATE: The pKa of boric acid is 9.24 at 25 °C(1), indicating that this compound will exist primarily in the undissociated form at an environmental pH range between 5 and 9, although the anion form will partially exist in alkaline waters(SRC). Boric acid leaches readily in soils(2) which indicates adsorption to suspended solids and sediment in water will not be an important fate process(SRC). Volatilization from water surfaces is not expected(3) based upon an estimated Henry's Law constant of 2.6X10-12 atm-cu m/mole(SRC), derived from its vapor pressure, 1.6X10-6 mm Hg(4), and water solubility, 5X10+4 mg/L(5). However, evaporation of seawater itself is reported to be the biggest environmental contribution of boric acid to air(2). No biotransformation processes have been reported for boron compounds, including boric acid(2).ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), boric acid, which has a vapor pressure of 1.6X10-6 mm Hg at 25 °C(2), will exist in both the vapor and particulate phases in the ambient atmosphere. One monitoring study found that approximately 90% of boric acid in the atmosphere is in gaseous form and 10% in particulate form(3). Vapor-phase boric acid 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 about 38 days(SRC), calculated from its rate constant of 4.2X10-13 cu cm/molecule-sec at 25 °C(SRC) that was derived using a structure estimation method(4). Particulate-phase boric acid may be removed from the air by wet or dry deposition(SRC). |
| Adverse effects | Neurotoxin - Other CNS neurotoxin |
| Exposure routes | The substance can be absorbed into the body by inhalation of dust and by ingestion. |
| Toxicity summary | The Expert Panel concludes that Sodium Borate and Boric Acid, in concentrations less than or equal to 5 percent, are safe as cosmetic ingredients when used as currently recommendedhowever, cosmetic formulations containing free Sodium Borate or Boric Acid at this concentration should not be used on infant skin or injured skin. Note: In 2003, the CIR Expert Panel considered available new data on these ingredients and reaffirmed the above conclusion.Safe for use in cosmetics, with qualifications |
| Ecotoxicity excerpts | /AQUATIC SPECIES/ As a contribution to the investigation of properties of macrophytic water plants as bio-indicators the submerged softwater-macrophytes Myriophyllum alterniflorum, Ranunculus penicillatus and Elodea canadensis were polluted in an aquarium system with oligotrophic, Ca-poor water up to 4 wk with increasing concentrations of /boron/ (B) (H3BO3-/boric acid/) and with different compounds of B. The effect of the test substances was measured as a change of the net photosynthesis. Low B concentrations up to 2 mg B/L, which can be found in highly polluted waters, had only a small negative effect on R. penicillatus and E. canadensis. Stronger damages occurred with 5 mg B/l on M. alterniflorum and with 10 mg/L on the other 2 spp. The toxicity of different B compounds to E. canadensis at 2 mg B/L increased from boric acid and perborate to metaborate and borax. Boron trioxide had no negative influence after 21 test days in comparison with the control. Ecophysiological tests demonstrated that M. alterniflorum is a highly competitive species in oligotrophic softwater. The opinion of B as an environmental hazard has to be revised. At least in softwater systems, B had a much higher toxicity than formerly assumed./AQUATIC SPECIES/ A static renewal procedure, with batch-wise replacement of test and control solutions at regular intervals...was... /conducted using Daphnia magna/. ... There were 4 replicates for each test concentration and the control, resulting in 5 daphnids per replicate or a total of 20 organisms per concentration. ...The chronic study began by placing one neonate in each tube, where the daphnid remained for the entire study. Each Monday, Wednesday, and Friday the young produced by each adult were counted and discarded, and adult survival was recorded. In addition, on the same days, the dissolved oxygen, pH, and temperature in each test concentration and the control were measured and recorded. After enumeration of the young, the adults were transferred to clean beakers containing fresh test and control solutions, in addition to a new supply of food. The boric acid test concentrations used for the chronic test were 7, 14, 28, 56, and 105 mg/L as boron. ...The mean boron concentration was 0, 6.4, 13.6, 29.4, and 59.3 at 0, 7, 14, 28, and 56 mg/L, respectively. ...Throughout the chronic test the dissolved oxygen and temperature ranged from 7.3-8.0 mg/L and 19.5-20.5 °C, respectively. Mortality during the 21-day test was 0, 0, 10, 5, and 40% at 0, 7, 14, 28, and 56 mg/L, respectively. /No/... daphnids exposed to the highest concentration of boric acid (105 mg/L as boron) ... survived to reproductive age. Time to first reproduction was not affected by the test concentrations. The mean number of broods per daphnid, mean total young per daphnid, mean brood size per daphnid, and mean size all differed significantly from control at 13.6 mg/L. It appeared that the most biologically, as well as statistically, important endpoints for this study were those associated with reproduction and growth. Therefore, determination of the /maximum acceptable toxicant concentration/ (MATC) was based on the endpoints of mean total young per replicate, mean brood size, and mean size. The MATC of boric acid was estimated to lie between 6.4 and 13.6 mg/L as boron./AQUATIC SPECIES/ Static 96-hr exposures /of Oncorhynchus tshawytscha (Chinook salmon) and Oncorhynchus kisutch (Coho salmon)/ were conducted in 19.6-L glass jars containing 15 L of test solution /of boric acid/ and maintained at 12 +/-1 °C in temperature-controlled water baths. Each test consisted of exposing groups of 10 fish to a series of toxicant concentrations that differed by 60% between treatments, and a control. For large, advanced fry, duplicate sets of jars were used and only 5 fish were stocked in each jar to maintain loading densities of 0.8 g/L or lower. Observations of mortality and abnormal behavioral responses were made at 24-hour intervals, and all dead fish were removed after each observation. In 1 set of tests, 2 life stages of Chinook salmon and Coho salmon were tested with boric acid. One life stage composed of swim-up fry 8-12 weeks old (post hatch) tested in fresh water. The 2nd life stage composed of advanced fry 15-21 weeks old tested in brackish water. Chinook salmon were also tested in soft water. In tests conducted in the 2 site-specific waters, pH was measured at the beginning and end of the test. Eyed eggs, alevins, and swim-up fry of Chinook salmon were tested in soft water to determine the relative sensitivity of those various life stages to boron. ...Groups of 25 eggs, 10 alevins, or 10 swim-up fry were exposed to a series of toxicant concentrations that differed by 56% between treatments, and a control. Criteria of death for eggs were the presence of an opaque (whitened) membrane. Alevins were examined under 30x magnification for the absence of a heartbeat, which was the criterion for death. The 24-hr LC50 of Chinook and Coho salmon (fresh or brackish water) was >1000 mg/L. Boron was relatively non-toxic. Young Coho salmon tested in fresh water were less tolerant than older fish tested in brackish water and Chinook salmon tested in either dilution water. The relative sensitivity of various early life stages of Chinook salmon to boron changed significantly as the fish developed. Fry were consistently more sensitive than either the embryos or alevins to boron. The pH in test concentrations and controls were not markedly different, ranging from 6.5 to 8.1. No significant differences in 96-hr LC50 values were found among dilution water qualities, thus indicating that differences in water quality characteristics tested did not modify the toxicity of these chemicals./AQUATIC SPECIES/ /Water flea/ screening test was performed for 48-hours /in which Ceriodaphnia dubia were exposed/ to nominal concentrations of 0, 0.10, 1, 10, 100, and 1000 mg/L /boric acid, purity >99%/. At the end of the test there was 0% survival at 1000 mg/L, 10% survival at 100 mg/L, and 100% survival at all lower concentrations. ...Water quality parameters were within acceptable limits throughout the study. Dissolved oxygen concentrations were always above 7.8 mg/L. During the test, the mean temperature was 24.4 °C, the mean conductivity was 350 umhos/cm, and the pH ranged from 7.1 to 8.3. Hardness ranged from 88 to 100 mg/L in control vessels and from 88 to 108 mg/L in vessels containing 100 mg/L of the test substance. Alkalinity ranged from 16 to 21 mg/L in control vessels and from 16 to 23 mg/L in vessels containing 100 mg/L of the test substance. The percentage of surviving adults was not significantly reduced at any tested concentration, and sublethal effects were not observed at any concentration. The mean number of young per surviving adult was significantly lower than the control at the 3 highest tested concentrations (25, 50, and 100 mg/L). The most sensitive biological endpoint was production of young. The NOEC, LOEC, and MATC were 12.5, 25, and 17.7 mg/L, respectively.For more Ecotoxicity Excerpts (Complete) data for BORIC ACID (12 total), please visit the HSDB record page. |
| Signs and Symptoms | Cough. Sore throat.No acute symptoms expected.Redness. Pain.Nausea. Vomiting. Diarrhoea. Abdominal pain. Skin rash. Headache. Drowsiness. Convulsions. |
| Ongoing Test Status | The following link will take the user to the National Toxicology Program (NTP) Test Agent Search Results page, which tabulates all of the "Standard Toxicology & Carcinogenesis Studies", "Developmental Studies", and "Genetic Toxicity Studies" performed with this chemical. Clicking on the "Testing Status" link will take the user to the status (i.e., in review, in progress, in preparation, on test, completed, etc.) and results of all the studies that the NTP has done on this chemical.[Available from: http://ntp-apps.niehs.nih.gov/ntp_tox/index.cfm?fuseaction=ntpsearch.searchresults&searchterm=10043-35-3] |
| Medical Surveillance | No specific considerations are needed for boric acid or borates except for general health and liver and kidney function. /Boric acid and borates/ |
| State drinking water guidelines | (CA) CALIFORNIA 1000 ug/L /Boron/(NH) NEW HAMPSHIRE 630 ug/L /Boron/(ME) MAINE 1,400 ug/L /Boron/(MN) MINNESOTA 1,000 ug/L /Boron/(WI) WISCONSIN 960 ug/L /Boron/ |
| Federal drinking water guidelines | EPA 600 ug/L /Boron/ |
| F | 3 |
| Water hazard class (WGK) | 2 |
| TSCA inventory status | TSCA listed |
| RTECS number | ED4550000 |
| Customs code | 28100090 |
| Toxicity | LD50 orally in rats: 5.14 g/kg (Smyth). |
| Risk statements (R) | 36/37/38-60-63-62-61 |
| Signal word | Danger |
| GHS pictogram | GHS08 |
| Hazard symbols | Xi,T,Xn |
| Safety statements (S) | 26-36-53-45-37/39-36/37/39-22-24/25-23 |
| Storage class | 6.1C - Combustible acute toxic Cat.3toxic compounds or compounds which causing chronic effects |
| GHS hazard statements | H360FD |
| REACH registrations | Active |
| Hazard class | Repr. 1B |
| GHS precautionary statements | P201-P202-P280-P308+P313-P405-P501 |
| Hazardous substances data | 10043-35-3(Hazardous Substances Data) |
Applications & Uses
Description
Boric acid is a monobasic acid that exhibits extremely weak acidity (Ka = 5.8 × 10⁻¹⁰), similar to silicic acid (K₁ = 2 × 10⁻¹⁰). Upon ionisation in water, it does not donate protons directly but instead forms a complex with hydroxide ions present in the solution:H₃BO₃ + 2H₂O → H₃O⁺ + B(OH)₄⁻This behaviour is related to the electron-deficient nature characteristic of boron compounds. In boric acid, the boron atom acts as an electron pair acceptor by bonding with a hydroxide ion, where the oxygen atom serves as the electron pair donor. Thus, boric acid is considered a typical Lewis acid.When glycerol or mannitol [CH₂(OH)(CHOH)₄CH₂OH] is added to a boric acid solution, its acidity increases. This is because boric acid forms a coordination complex (anion) with glycerol, which facilitates the release of H⁺ ions, thereby enhancing ionisation.In the crystal structure of boric acid, the fundamental unit is the planar triangular BO₃ group. Each boron atom undergoes sp² hybridisation, and each oxygen atom forms a covalent bond with a boron atom, while also interacting with two hydrogen atoms through covalent and hydrogen bonding. These interactions give rise to layered, sheet-like macromolecular structures. Upon heating, the weak hydrogen bonds are disrupted, leading to disintegration of the macromolecular sheets and an increase in solubility.
History
The discovery and utilization of borax dates back to ancient Egypt, where it was used as a flux in glass production. The chemical composition of boric acid remained an enigma until the early 19th century, when it was first employed by alchemists.In 1702, the French physician Homberg first reacted borax (Na₂B₄O₇·10H₂O) with sulfuric acid to produce boric acid, naming it "salsedativum"(sedative salt). This reaction laid the foundation for the early production of boric acid.In 1741, the French chemist Pott further investigated the reaction and discovered that it also produced sodium sulfate, revealing the double displacement nature of borax's reaction with acids.
Uses
Boric acid can be used to study molecular biology, DNA and RNA purification, biological buffers and molecular biology reagents. Boric acid has been used to test the toxic effects of boron on growth and antioxidant system parameters of maize (Zea mays L.) roots. Boric acid has also been used to study the effect of time period after boric acid injection on (10)B absorption in different regions of adult male rat′s brain.
General Description
Boric acid is a weak monobasic acid, it accepts OH- ions, hence is a Lewis acid. In boric acid, B is sp2 hybridized, forming a planar triangle structure. The principal oxide of boron, B2O3, is obtained as a vitreous solid by dehydration of boric acid at red heat.
Preparation & Synthesis
Preparation
Boric acid is produced from borax, colemanite, or other inorganic borates by reaction with sulfuric acid or hydrochloric acid, and cooling the solution to proper temperature:Na2B4O7 10Η2Ο + H2SO4 → 4H3BO3 + Na2SO4 + 5H2OIt also may be prepared by extraction of weak borax brine with a kerosene solution of an aromatic diol, such as 2-ethyl-1,3-hexanediol or 3-chloro- 2-hydroxy-5-(1,1,3,3-tetramethylbutyl)benzyl alcohol. The diol-borate chelate formed separates into a kerosene phase. Treatment with sulfuric acid yields boric acid which partitions into aqueous phase and is purified by recrystallization.