1,4-Benzoquinone

IARC Cancer Review: Group 3 IMEMDT IARC Monographs on the Evaluation of Carcinogenic Risk of Chemicals to Man . 7 ,1987,p. 56.(World Health Organization, Internation Agency for Research on Cancer,Lyon, France.: ) (Single copies can be ordered from WHO Publications Centre U.S.A.,49 Sheridan Avenue, Albany, NY 12210) ; Animal Inadequate Evidence IMEMDT    IARC Monographs on the Evaluation of Carcinogenic Risk of Chemicals to Man . 15 ,1977,p. 255.(World Health Organization, Internation Agency for Research on Cancer,Lyon, France.: ) (Single copies can be ordered from WHO Publications Centre U.S.A., 49 Sheridan Avenue, Albany, NY 12210) . Reported in EPA TSCA Inventory. Community Right-To-Know List. EPA Genetic Toxicology Program.

OSHA PEL: TWA 0.1 ppm
ACGIH TLV: TWA 0.1 ppm
DFG MAK: 0.1 ppm (0.45 mg/m³)
DOT Classification:  6.1; Label: Poison

The 1,4-Benzoquinone, with the CAS registry number 106-51-4,is also known as 2,5-Cyclohexadiene-1,4-dione; Quinone; Quinone; p-Benzoquinone 98+ % (dried); 2,5-Cyclohexadiene-1,4-dione. It belongs to the product categories of Charge Transfer Complexes for Organic Metals;Benzoquinones;Functional Materials.This chemical's molecular formula is C₆H₄O₂ and molecular weight is 108.09.Its EINECS number is 203-405-2. What's more,Its systematic name is p-Benzoquinone.It is a yellowish-colored crystalline solid with a pungent, irritating odor. Poisonous by ingestion or inhalation of vapors. May severely damage skin, eyes and mucous membranes. Used to make dyes and as a photographic chemical.

Physical properties about 1,4-Benzoquinone are:
(1)ACD/LogP:  0.394; (2)# of Rule of 5 Violations:  0; (3)ACD/LogD (pH 5.5):  0.39; (4)ACD/LogD (pH 7.4):  0.39; (5)ACD/BCF (pH 5.5):  1.17; (6)ACD/BCF (pH 7.4):  1.17; (7)ACD/KOC (pH 5.5):  39.05; (8)ACD/KOC (pH 7.4):  39.05; (9)#H bond acceptors:  2; (10)#H bond donors:  0; (11)#Freely Rotating Bonds:  0; (12)Index of Refraction:  1.543; (13)Molar Refractivity:  27.139 cm3; (14)Molar Volume:  86.036 cm3; (15)Surface Tension:  47.8059997558594 dyne/cm; (16)Density:  1.256 g/cm3; (17)Flash Point:  59.33 °C; (18)Enthalpy of Vaporization:  41.035 kJ/mol; (19)Boiling Point:  174.004 °C at 760 mmHg; (20)Vapour Pressure:  1.23199999332428 mmHg at 25°C.

Use of 1,4-Benzoquinone:
1,4-Benzoquinone is used as a dye and pharmaceutical intermediate, rubber antioxidant, inhibitor, anti-oxidants, reagent,oxidant. It is also used in organic synthesis such as for the synthesis of hydroquinone.

Preparation of 1,4-Benzoquinone:
1,4-Benzoquinone can be prepared by the oxidation of benzene, aniline, and hydroquinone by a miscellany of oxidizing agents. The oxidation of hydroquinone is rapid and convenient and therefore desirable for the laboratory. 1,4-Benzoquinone can be prepared from hydroquinone via a number of oxidation methods. One such method makes use of hydrogen peroxide as the oxidizer and iodine or an iodine salt as a catalyst for the oxidation occurring in a polar solvent; e.g. isopropyl alcohol.
When heated to its melting point, the product sublimates at atmospheric pressure, and, when prepared from hydroquinone, the substrate boils at a significantly higher temperature than 1,4-benzoquinones melting point, allowing for an effective separation of the two. Impure samples are often dark-colored due to the presence of quinhydrone (1:1 complex of quinone with hydroquinone). When prepared by methods involving iodine (an element with a characteristically intense stain), traces of iodine contamination in the product may also darken its appearance. 1,4-Benzoquinone's high vapour pressure at room temperature means that containers should be well sealed to prevent its gradual sublimation into the atmosphere whilst in storage.

You can still convert the following datas into molecular structure:
(1)SMILES:C1=CC(=O)C=CC1=O;
(2)Std. InChI:InChI=1S/C6H4O2/c7-5-1-2-6(8)4-3-5/h1-4H;
(3)Std. InChIKey:AZQWKYJCGOJGHM-UHFFFAOYSA-N;

Safety Information of 1,4-Benzoquinone:
The 1,4-Benzoquinone is Toxic by inhalation and if swallowed. 
It is irritating to eyes, respiratory system and skin  and Harmful by inhalation, in contact with skin and if swallowed.So after contact with skin, wash immediately with plenty of water (to be specified by the manufacturer).In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. And it is very Toxic to aquatic organisms ,so it should be avoid release to the environment. Refer to special instructions safety data sheet.Do not breathe gas/fumes/vapor/spray (appropriate wording to be specified by the manufacturer) .In case of accident or if you feel unwell, seek medical advice immediately (show label where possible) .This chemical is highly Flammable,keep away from sources of ignition - No smoking.

The toxicity data of 1,4-Benzoquinone as follows: