4-Hydroxybenzoic acid
CAS No.: 99-96-7 Formula: C7H6O3 Molecular Weight: 138.12100
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4-Hydroxybenzoic acid

CAS No.: 99-96-7 Formula: C7H6O3 Molecular Weight: 138.12100
Suppliers: All (256) China Suppliers (168) Price Available (45) Contractor (6)


4-Hydroxybenzoic acid, also known as p-hydroxybenzoic acid (PHBA), is a monohydroxybenzoic acid, a phenolic derivative of benzoic acid. It is a white crystalline solid that is slightly soluble in water and chloroform but more soluble in polar organic solvents such as alcohols and acetone. 4-Hydroxybenzoic acid is primarily known as the basis for the preparation of its esters, known as parabens, which are used as preservatives in cosmetics and some ophthalmic solutions. It is isomeric with 2-hydroxybenzoic acid, known as salicylic acid, a precursor to aspirin.

Numbering system

EINECS number 202-804-9
MDL number MFCD00002547


Appearance & Physical State White to beige crystalline powder
Density 1.46 g/cm3
Boiling Point 336.2ºC at 760 mmHg
Melting Point 214-217ºC
Flash Point 199ºC
Refractive Index 1.53
Water Solubility 5 g/L (20 ºC)
Stability Stable under normal temperatures and pressures.
Storage Condition Store in a cool, dry place. Keep container closed when not in use.

Safety Info

RTECS DH1925000
Safety Statements S26-S37/39
HS Code 2916399090
WGK Germany 1
Risk Statements R36/37/38
Hazard Codes Xi
SDS 1.0 Expand

SDS 1.0

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According to Globally Harmonized System of Classification and Labelling of Chemicals (GHS) - Sixth revised edition

Version: 1.0

Creation Date: Aug 12, 2017

Revision Date: Aug 12, 2017


1.1 GHS Product identifier

Product name 4-Hydroxybenzoic acid

1.2 Other means of identification

Product number -
Other names Benzoic acid,4-hydroxy-

1.3 Recommended use of the chemical and restrictions on use

Identified uses For industry use only. Food additives -> Flavoring Agents
Uses advised against no data available

1.4 Supplier's details

Company MOLBASE (Shanghai) Biotechnology Co., Ltd.
Address Floor 4 & 5, Building 12, No. 1001 North Qinzhou Road,
Xuhui District, Shanghai, China
Telephone +86(21)64956998
Fax +86(21)54365166

1.5 Emergency phone number

Emergency phone number +86-400-6021-666
Service hours Monday to Friday, 9am-5pm (Standard time zone: UTC/GMT +8 hours).

2.Hazard identification

2.1 Classification of the substance or mixture

Serious eye damage, Category 1

Specific target organ toxicity – single exposure, Category 3

Specific target organ toxicity – single exposure, Category 3

2.2 GHS label elements, including precautionary statements

Signal word


Hazard statement(s)

H318 Causes serious eye damage

H335 May cause respiratory irritation

H335 May cause respiratory irritation

Precautionary statement(s)

P280 Wear protective gloves/protective clothing/eye protection/face protection.

P261 Avoid breathing dust/fume/gas/mist/vapours/spray.

P271 Use only outdoors or in a well-ventilated area.


P305+P351+P338 IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.

P310 Immediately call a POISON CENTER/doctor/…

P304+P340 IF INHALED: Remove person to fresh air and keep comfortable for breathing.

P312 Call a POISON CENTER/doctor/…if you feel unwell.


P403+P233 Store in a well-ventilated place. Keep container tightly closed.

P405 Store locked up.


P501 Dispose of contents/container to ...

2.3 Other hazards which do not result in classification


3.Composition/information on ingredients

3.1 Substances

Chemical name Common names and synonyms CAS number EC number Concentration
4-Hydroxybenzoic acid 4-Hydroxybenzoic acid 99-96-7 none 100%

4.First-aid measures

4.1 Description of necessary first-aid measures

General advice

Consult a physician. Show this safety data sheet to the doctor in attendance.

If inhaled

If breathed in, move person into fresh air. If not breathing, give artificial respiration. Consult a physician.

In case of skin contact

Wash off with soap and plenty of water. Consult a physician.

In case of eye contact

Rinse thoroughly with plenty of water for at least 15 minutes and consult a physician.

If swallowed

Never give anything by mouth to an unconscious person. Rinse mouth with water. Consult a physician.

4.2 Most important symptoms/effects, acute and delayed

no data available

4.3 Indication of immediate medical attention and special treatment needed, if necessary

Absorption, Distribution and Excretion

...Groups of 4-8 rabbits were given 4-hydroxybenzoic acid at a dose of 100, 250, 500, 1000, or 1500 mg/kg bw by gavage every 3-7 days. Urine was collected continuously and analysed for metabolites. The total urinary recovery of the test material ranged from 84% to 104%. Glucuronic acid and sulfate conjugates were also detected in the urine, at 10-35% and 4-7%, respectively. The concentrations of all the metabolites returned to background values within 24 hr after dosing.

5.Fire-fighting measures

5.1 Extinguishing media

Suitable extinguishing media

Use water spray, alcohol-resistant foam, dry chemical or carbon dioxide.

5.2 Specific hazards arising from the chemical

no data available

5.3 Special protective actions for fire-fighters

Wear self-contained breathing apparatus for firefighting if necessary.

6.Accidental release measures

6.1 Personal precautions, protective equipment and emergency procedures

Use personal protective equipment. Avoid dust formation. Avoid breathing vapours, mist or gas. Ensure adequate ventilation. Evacuate personnel to safe areas. Avoid breathing dust. For personal protection see section 8.

6.2 Environmental precautions

Prevent further leakage or spillage if safe to do so. Do not let product enter drains. Discharge into the environment must be avoided.

6.3 Methods and materials for containment and cleaning up

Pick up and arrange disposal. Sweep up and shovel. Keep in suitable, closed containers for disposal.

7.Handling and storage

7.1 Precautions for safe handling

Avoid contact with skin and eyes. Avoid formation of dust and aerosols. Avoid exposure - obtain special instructions before use.Provide appropriate exhaust ventilation at places where dust is formed. For precautions see section 2.2.

7.2 Conditions for safe storage, including any incompatibilities

Store in cool place. Keep container tightly closed in a dry and well-ventilated place.

8.Exposure controls/personal protection

8.1 Control parameters

Occupational Exposure limit values

no data available

Biological limit values

no data available

8.2 Appropriate engineering controls

Handle in accordance with good industrial hygiene and safety practice. Wash hands before breaks and at the end of workday.

8.3 Individual protection measures, such as personal protective equipment (PPE)

Eye/face protection

Safety glasses with side-shields conforming to EN166. Use equipment for eye protection tested and approved under appropriate government standards such as NIOSH (US) or EN 166(EU).

Skin protection

Wear impervious clothing. The type of protective equipment must be selected according to the concentration and amount of the dangerous substance at the specific workplace. Handle with gloves. 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. The selected protective gloves have to satisfy the specifications of EU Directive 89/686/EEC and the standard EN 374 derived from it.

Respiratory protection

Wear dust mask when handling large quantities.

Thermal hazards

no data available

9.Physical and chemical properties

Physical state White to beige crystalline powder
Colour White granular crystalline powder consisting of monoclinic prisms
Odour no data available
Melting point/ freezing point 320°C(dec.)(lit.)
Boiling point or initial boiling point and boiling range 214°C(lit.)
Flammability no data available
Lower and upper explosion limit / flammability limit no data available
Flash point 88°C(lit.)
Auto-ignition temperature no data available
Decomposition temperature no data available
pH no data available
Kinematic viscosity no data available
Solubility In water:5 g/L (20 ºC)
Partition coefficient n-octanol/water (log value) log Kow=1.58
Vapour pressure 1.9X10-7 mm Hg at 25°C /Extrapolated/
Density and/or relative density 1.46 g/cm3
Relative vapour density no data available
Particle characteristics no data available

10.Stability and reactivity

10.1 Reactivity

no data available

10.2 Chemical stability

Stable under recommended storage conditions.

10.3 Possibility of hazardous reactions

no data available

10.4 Conditions to avoid

no data available

10.5 Incompatible materials

no data available

10.6 Hazardous decomposition products

When heated to decomposition it emits acrid smoke and irritating fumes.

11.Toxicological information

Acute toxicity

  • Oral: LD50 Mouse oral 2200 mg/kg
  • Inhalation: no data available
  • Dermal: no data available

Skin corrosion/irritation

no data available

Serious eye damage/irritation

no data available

Respiratory or skin sensitization

no data available

Germ cell mutagenicity

no data available


no data available

Reproductive toxicity

no data available

STOT-single exposure

no data available

STOT-repeated exposure

no data available

Aspiration hazard

no data available

12.Ecological information

12.1 Toxicity

  • Toxicity to fish: LC50 Oncorhynchus mykiss (Rainbow trout) >99 mg/L/96 hr /Conditions of bioassay not specified in source examined
  • Toxicity to daphnia and other aquatic invertebrates: EC50 Daphnia magna (intoxication, immobilization) 181 mg/L/24 hr (95% confidence interval: 167-198 mg/L); 173 mg/L/48 hr; static
  • Toxicity to algae: no data available
  • Toxicity to microorganisms: no data available

12.2 Persistence and degradability

AEROBIC: In a 1% soil suspension screening test, 4-hydroxybenzoic acid at 25 ppm was completely degraded within 1 day, as measured by loss of UV absorbancy(1). 4-Hydroxybenzoic acid was readily biodegraded in several aerobic activated sludge screening tests including the Zahn-Wellens test (100% removal in 1 day), Japanese MITI test (98% theoretical BOD reached in 14 days), Sturm CO2 evolution test (61% theoretical CO2 produced in 28 days), OECD Screening test (95% DOC removal in 19 days), and the Closed bottle test (93% theoretical BOD reached in 30 days)(2). In an OECD coupled units biological treatment simulation test, 99% DOC removal of 4-hydroxybenzoic acid, initially present at 12 ppm C, was reported after an acclimation period of 7 days(2). 4-Hydroxybenzoic acid was mineralized 44 to 54% in 14 days in an assay where aquifer sediments from outside the coal-tar contaminated plume were added to the compound in distilled water at 20°C(3). When aquifer sediment collected from within the plume were used, from 50 to over 80% of the added 4-hydroxybenzoic acid was generally mineralized within 14 days(3). Under microaerophilic conditions, mineralization of 4-hydroxybenzoic acid ranged from 13 to 54% in 6 days; sediment collected from within the plume was used as an inoculum(3). Under aerobic conditions, using the same sediment, from 34 to 70% mineralization was reported over the same time(3). The percent 4-hydroxybenzoic acid mineralization in 20 days ranged from 35 to 55, 35 to 55, and 0 to 35 in microcosms using sediment upgradient of a coal-tar contaminated plume, downgradient of the plume, and in pristine sediment, respectively(4). Mineralization of 4-hydroxybenzoic acid in aquifer sediment microcosms from uncontaminated and contaminated boreholes in an urban coal-tar waste site was reported as 43 to 51% and 46 to 52%, respectively, in 14 days(5).

12.3 Bioaccumulative potential

An estimated BCF of 9 was calculated for 4-hydroxybenzoic acid(SRC), using a log Kow of 1.58(1) and a regression-derived equation(2). According to a classification scheme(3), this BCF suggests the potential for bioconcentration in aquatic organisms is low(SRC), provided the compound is not altered physically or chemically once released into the environment.

12.4 Mobility in soil

Koc values of 142, 20, and 14 were measured according to a modified version of OECD guideline 106 for 4-hydroxybenzoic acid in a podzol (pH=2.8, C organic=4.85%, sand:silt:clay=89.2:8.2:2.6%), alfisol (pH=6.7, C organic=1.25%, sand:silt:clay=69.7:14.4:15.9%), and a sediment (pH=7.1, C organic=1.58%, sand:silt:clay=5.5:58.8:35.7%), respectively(1). According to a classification scheme(2), these Koc values suggest that 4-hydroxybenzoic acid is expected to have high to very high mobility in soil. The pKa of 4-hydroxybenzoic acid is 4.54(3), indicating that this compound will primarily exist in anion form in the environment and anions generally do not adsorb more strongly to organic carbon and clay than their neutral counterparts(4).

12.5 Other adverse effects

no data available

13.Disposal considerations

13.1 Disposal methods


The material can be disposed of by removal to a licensed chemical destruction plant or by controlled incineration with flue gas scrubbing. Do not contaminate water, foodstuffs, feed or seed by storage or disposal. Do not discharge to sewer systems.

Contaminated packaging

Containers can be triply rinsed (or equivalent) and offered for recycling or reconditioning. Alternatively, the packaging can be punctured to make it unusable for other purposes and then be disposed of in a sanitary landfill. Controlled incineration with flue gas scrubbing is possible for combustible packaging materials.

14.Transport information

14.1 UN Number

ADR/RID: UN2735 IMDG: UN2735 IATA: UN2735

14.2 UN Proper Shipping Name


14.3 Transport hazard class(es)


14.4 Packing group, if applicable


14.5 Environmental hazards

ADR/RID: no IMDG: no IATA: no

14.6 Special precautions for user

no data available

14.7 Transport in bulk according to Annex II of MARPOL 73/78 and the IBC Code

no data available

15.Regulatory information

15.1 Safety, health and environmental regulations specific for the product in question

Chemical name Common names and synonyms CAS number EC number
4-Hydroxybenzoic acid 4-Hydroxybenzoic acid 99-96-7 none
European Inventory of Existing Commercial Chemical Substances (EINECS) Listed.
EC Inventory Listed.
United States Toxic Substances Control Act (TSCA) Inventory Listed.
China Catalog of Hazardous chemicals 2015 Not Listed.
New Zealand Inventory of Chemicals (NZIoC) Listed.
Philippines Inventory of Chemicals and Chemical Substances (PICCS) Listed.
Vietnam National Chemical Inventory Listed.
Chinese Chemical Inventory of Existing Chemical Substances (China IECSC) Listed.

16.Other information

Information on revision

Creation Date Aug 12, 2017
Revision Date Aug 12, 2017

Abbreviations and acronyms

  • CAS: Chemical Abstracts Service
  • ADR: European Agreement concerning the International Carriage of Dangerous Goods by Road
  • RID: Regulation concerning the International Carriage of Dangerous Goods by Rail
  • IMDG: International Maritime Dangerous Goods
  • IATA: International Air Transportation Association
  • TWA: Time Weighted Average
  • STEL: Short term exposure limit
  • LC50: Lethal Concentration 50%
  • LD50: Lethal Dose 50%
  • EC50: Effective Concentration 50%


  • IPCS - The International Chemical Safety Cards (ICSC), website: http://www.ilo.org/dyn/icsc/showcard.home
  • HSDB - Hazardous Substances Data Bank, website: https://toxnet.nlm.nih.gov/newtoxnet/hsdb.htm
  • IARC - International Agency for Research on Cancer, website: http://www.iarc.fr/
  • eChemPortal - The Global Portal to Information on Chemical Substances by OECD, website: http://www.echemportal.org/echemportal/index?pageID=0&request_locale=en
  • CAMEO Chemicals, website: http://cameochemicals.noaa.gov/search/simple
  • ChemIDplus, website: http://chem.sis.nlm.nih.gov/chemidplus/chemidlite.jsp
  • ERG - Emergency Response Guidebook by U.S. Department of Transportation, website: http://www.phmsa.dot.gov/hazmat/library/erg
  • Germany GESTIS-database on hazard substance, website: http://www.dguv.de/ifa/gestis/gestis-stoffdatenbank/index-2.jsp
  • ECHA - European Chemicals Agency, website: https://echa.europa.eu/

Disclaimer: The above information is believed to be correct but does not purport to be all inclusive and shall be used only as a guide. The information in this document is based on the present state of our knowledge and is applicable to the product with regard to appropriate safety precautions. It does not represent any guarantee of the properties of the product. We as supplier shall not be held liable for any damage resulting from handling or from contact with the above product.
MSDS Expand
1H NMR : 90 MHz in DMSO-d6Expand

NMR Spectrum 1H NMR : 90 MHz in DMSO-d6


C7 H6 O3 0.047 g : 0.5 ml DMSO-d6
p-hydroxybenzoic acid

Assign. Shift(ppm)
A *1 12.4
B *1 10.2
C 7.80
D 6.84

IR : KBr discExpand
Mass Expand
Raman : 4880 A,200 M,powderExpand

GC Analysis

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Capillary HP-5 MS - 1558. temperature ramp
Capillary HP-5 MS - 1558. temperature ramp
Capillary HP-5 MS - 1558. temperature ramp
Capillary HP-5MS - 1577. custom temperature program
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