Ingredient Dictionary

TBHQ

2-tert-butylhydroquinone is a member of the class of hydroquinones in which one of the ring hydrogens of hydroquinone is replaced by a tert-butyl group.

How much products actually contain

No product states its amount yet.

Of the products containing it, 0 list it before the 1% line and 10 after it (usually 1% or less).

Products using this ingredient

10 of 10 confirmed · likeliest to carry enough first

Definition

2-tert-butylhydroquinone is a member of the class of hydroquinones in which one of the ring hydrogens of hydroquinone is replaced by a tert-butyl group. It has a role as a food antioxidant.

Source: PubChem

US FDA substance register · UNII C12674942B · registered name TERT-BUTYLHYDROQUINONE · single chemical substance

Source: US FDA Unique Ingredient Identifier (UNII)

Cosmetic roles

Listed as a fragrance-composition material (not a claim that it adds scent)FRAGRANCESlows spoilage by oxygenANTIOXIDANTGives the product a scentPERFUMING

Safety & regulatory references

Canada

Conditions of Use by product type : (a) Hair waving and straightening products
Maximum Concentration Permitted : 0.1%

Source: MFDS (Korea) cosmetic regulatory information

Not classified under Korea’s toxic-substance GHS list · existing chemical substance

Source: Korea toxic substances GHS register (NIER)

Other restriction: ban substances that deplete the ozone layer

Source: EU CosIng ingredient list

Reviewed by CIR: Annual Review of Cosmetic Ingredient Safety Assessments: 2007-2010

Source: US Cosmetic Ingredient Review (CIR)

More data — names, identifiers, properties, test records, literature

Official labels & definitions

JCIA labelling name ＴＢＨＱ: 本品は、次の化学式で表される環式化合物である。

Source: JCIA labelling names (Japan)

Names & identifiers

TBHQINCI티비에이치큐Korean label name (MFDS standard)1,4-Benzenediol, 2-(1,1-dimethylethyl)-Synonym

CAS No.chemical registry number: 1948-33-0
EC No.EU chemical inventory number: 217-752-2
DTXSIDUS EPA chemical ID: DTXSID6020220
DTXCIDUS EPA compound ID: DTXCID60220

IUPAC: 2-tert-Butylbenzene-1,4-diol
Molecular formula: C10H14O2
Molecular weight: 166.22 g/mol

Measured properties

Appearance: Tert-butylhydroquinone appears as white to light tan crystalline powder or a fine beige powder. Very slight aromatic odor. (NTP, 1992) · Dry Powder, Liquid, Wet Solid, Other Solid
Odour: Very slight aromatic odor · Characteristic odor
Boiling point: 563 °F at 760 mmHg (NTP, 1992) · 295 °C
Melting point: 261 to 264 °F (NTP, 1992) · 126.5-128.5 °C
Solubility: less than 1 mg/mL at 66 °F (NTP, 1992) · Practically insoluble in water, soluble in ethanol
Density: 1.05 (NTP, 1992) - Denser than water, will sink · 1.05
Stability: Stable under recommended storage conditions.
pH: pH = 4.56 at 25 °C of a 1% solution of 2-tert-butylhydroquinone
Dissociation constant: pKa = 10.7 at 22 °C
Melting/freezing point: 125~129 ℃
Initial boiling point and range: 295 ℃
Flash point: 171 ℃((c.c))
Vapour pressure: 0.000217 ㎜Hg (at 25C(est.))
Water solubility: 748 ㎎/ℓ (at 25C(est.))
n-Octanol/water partition coefficient (Kow): 2.94 ((est.))
Molecular weight: 166.22

Values measured on the substance itself. The KOSHA data are a reference for writing and reviewing safety data sheets, not a specification for a commercial raw material.

Source: PubChem · KOSHA safety data sheets (Korea)

What products actually use it for

What the 15 products reported to the US EPA with this ingredient use it for. Products outside cosmetics are included, so the top few rows are its main uses.

Antioxidant6
Fragrance4
Deodorizer2
Processing aids not otherwise specified1
Catalyst1
Monomers1

Source: US EPA CompTox dashboard

Irritation and sensitisation studies

9 skin studies and 3 eye studies are on record.

Classed as highly irritating1Classed as low2

The studies disagree (the most common conclusion covers 33%), so they do not establish that this ingredient is irritating. These tests are on the raw material itself; irritation at the amount in a finished product is a different question.

See all 12 studies

Category 6.5B (Category 1)
Skin Sensitization · Read Across
Category 6.3A (Category 2)
Skin Irritation · Read Across
Not likely to be sensitizing
skin sensitisation · Screening · according to other guideline:
Severe Irritation
skin irritation: in vivo · Screening · other guideline: according to
SkinIrr2
Skin Irritation · QSAR Predicted
SkinSens1
Skin Sensitization · QSAR Predicted
Category 1
Skin Sensitization · Screening
Classification not possible
Skin Irritation · Screening
Not likely to be sensitizing
skin sensitisation: in vivo (non-LLNA) · Screening · according to other guideline:
Category 6.4A (Category 2A)
Eye Irritation · Read Across
Classification not possible
Eye Irritation · Screening
Severe Irritation
eye irritation: in vivo · Screening · other guideline: according to