2,5-Di-tert-butylhydroquinone
[CAS# 88-58-4]

Identification

• Classification: Chemical reagent >> Organic reagent >> Phenols
• Name: 2,5-Di-tert-butylhydroquinone
• Synonyms: Dibutylhydroquinone; BHQ; 2,5-Ditertiary butyl hydroquinone; Antioxidant DTBHQ
• Molecular Formula: C₁₄H₂₂O₂
• Molecular Weight: 222.33
• CAS Registry Number: 88-58-4
• EC Number: 201-841-8
• SMILES: CC(C)(C)C1=CC(=C(C=C1O)C(C)(C)C)O

Properties

• Solubility: Soluble 100 mM (DMSO)
• Density: 1.0±0.1 g/cm³, Calc.^*, 1.07 g/mL
• Melting point: 216-218 °C
• Index of Refraction: 1.520, Calc.^*
• Boiling Point: 334.4±37.0 °C (760 mmHg), Calc.^*, 321 °C
• Flash Point: 151.5±21.1 °C, Calc.^*, 216 °C

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software.

Safety Data

• Hazard Symbols: GHS06;GHS07;GHS08;GHS09 Danger
• Risk Statements: H301-H302-H315-H317-H319-H335-H373-H400-H410-H413
• Safety Statements: P260-P261-P264-P264+P265-P270-P271-P272-P273-P280-P301+P316-P301+P317-P302+P352-P304+P340-P305+P351+P338-P319-P321-P330-P332+P317-P333+P317-P337+P317-P362+P364-P391-P403+P233-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Specific target organ toxicity - single exposure	STOT SE	3	H335
Acute toxicity	Acute Tox.	4	H302
Eye irritation	Eye Irrit.	2	H319
Skin irritation	Skin Irrit.	2	H315
Chronic hazardous to the aquatic environment	Aquatic Chronic	1	H410
Acute hazardous to the aquatic environment	Aquatic Acute	1	H400
Acute toxicity	Acute Tox.	3	H301
Skin sensitization	Skin Sens.	1B	H317
Specific target organ toxicity - repeated exposure	STOT RE	2	H373
Chronic hazardous to the aquatic environment	Aquatic Chronic	4	H413
Skin sensitization	Skin Sens.	1A	H317
Chronic hazardous to the aquatic environment	Aquatic Chronic	2	H411
Specific target organ toxicity - single exposure	STOT SE	2	H371

Discovery and Applications

2,5-Di-tert-butylhydroquinone (DBHQ) is an organic compound known for its significant role as an antioxidant in various industrial applications. This compound is classified as a phenolic antioxidant and is characterized by the presence of two bulky tert-butyl groups at the 2 and 5 positions of the hydroquinone structure. The discovery of DBHQ can be traced back to the mid-20th century when researchers were exploring new compounds to enhance the stability and shelf life of materials prone to oxidative degradation.

The synthesis of DBHQ was motivated by the growing need for effective antioxidants that could protect polymers, rubber, and other materials from oxidative stress caused by environmental factors such as heat, light, and oxygen. Its unique structure allows DBHQ to effectively scavenge free radicals, which are the primary agents responsible for the oxidative degradation of materials. By donating hydrogen atoms to these radicals, DBHQ disrupts the chain reaction of oxidation, thereby preserving the integrity of the materials to which it is added.

DBHQ has found extensive applications in the plastics and rubber industries. In these sectors, it is used as a stabilizer to enhance the thermal and oxidative stability of polymer products. The addition of DBHQ to polymers not only prolongs their lifespan but also maintains their mechanical and physical properties, which is crucial for ensuring product performance. This is particularly important in applications where materials are subjected to high temperatures or harsh environmental conditions.

Another significant application of DBHQ is in the food industry, where it acts as a food preservative. Its antioxidant properties help prevent the rancidity of fats and oils, thus extending the shelf life of food products. By inhibiting oxidative reactions, DBHQ contributes to maintaining the flavor, color, and nutritional quality of food items, making it a valuable ingredient in food formulations.

DBHQ is also utilized in the formulation of cosmetics and personal care products, where it serves to protect sensitive ingredients from oxidative damage. The compound's ability to stabilize emulsions and prevent discoloration enhances the overall quality and efficacy of cosmetic formulations. This has made DBHQ a popular choice among manufacturers aiming to improve the stability and shelf life of their products.

Research continues to explore the broader implications of DBHQ, particularly regarding its safety and environmental impact. While DBHQ is generally regarded as safe for use in various applications, ongoing studies aim to assess its long-term effects and potential alternatives that may be more environmentally friendly.

In conclusion, the discovery of 2,5-Di-tert-butylhydroquinone has led to significant advancements in the fields of materials science, food preservation, and cosmetics. Its effectiveness as an antioxidant and stabilizer has made it a valuable compound across various industries, contributing to the enhancement of product quality and longevity. The ongoing research into its applications underscores the importance of chemical innovation in addressing the challenges posed by oxidation in everyday products.

References

2015. A Facile and Selective Procedure for Oxidation of Hydroquinones using Silica Gel Supported Catalytic Cerium(IV) Ammonium Nitrate. Synthesis, 47(14).
DOI: 10.1055/s-0034-1380439

1987. 2,5-Di(tert-butyl)-1,4-benzohydroquinone — a novel inhibitor of liver microsomal Ca2+ sequestration. FEBS Letters, 226(1).
DOI: 10.1016/0014-5793(87)80479-9

2022. Tert-butylhydroquinone: structural elucidation of a new polymorphic form. Journal of Thermal Analysis and Calorimetry, 148(20).
DOI: 10.1007/s10973-022-11627-7