Name | 1,4-Benzoquinone |
Synonyms | PBQ pbq2 Quinone p-Chinon P-quinone Benzoquinone p-Benzochinon p-Benzoquinone 1,4-Benzoquine 1,4-Benzochinon 1,4-Benzoquinone 1,4-Cyclohexadienedione quinone(p-benzoquinone) 1,4-Cyclohexadiene dioxide cyclohexa-3,5-diene-1,2-dione cyclohexa-2,5-diene-1,4-dione |
CAS | 106-51-4 |
EINECS | 203-405-2 |
InChI | InChI=1/C6H4O2/c7-5-3-1-2-4-6(5)8/h1-4H |
InChIKey | AZQWKYJCGOJGHM-UHFFFAOYSA-N |
Molecular Formula | C6H4O2 |
Molar Mass | 108.09 |
Density | 1.31 |
Melting Point | 113-115°C(lit.) |
Boling Point | 293°C |
Flash Point | 38°C |
Water Solubility | 10 g/L (25 ºC) |
Solubility | 10g/l |
Vapor Presure | 0.1 mm Hg ( 25 °C) |
Vapor Density | 3.73 (vs air) |
Appearance | Powder |
Color | Yellow to green |
Exposure Limit | TLV-TWA 0.4 mg/m3 (0.1 ppm); STEL 1.2mg/m3 (0.3 ppm) (ACGIH); IDLH 75 ppm(NIOSH). |
Merck | 14,8074 |
BRN | 773967 |
pKa | 7.7 |
PH | 4 (1g/l, H2O, 20℃) |
Storage Condition | room temp |
Stability | Stable, but light sensitive. Incompatible with strong oxidizing agents. Flammable. |
Refractive Index | n20/D 1.453 |
Physical and Chemical Properties | Yellow crystal. Irritating odor. melting point 116 ℃ relative density 1.318 solubility: soluble in ethanol, ether and alkali, slightly soluble in water. |
Use | For the preparation of hydroquinone, used as dyes and pharmaceutical intermediates, rubber antioxidant, polymerization inhibitor, antioxidant, developer, etc |
Risk Codes | R23/25 - Toxic by inhalation and if swallowed. R36/37/38 - Irritating to eyes, respiratory system and skin. R50 - Very Toxic to aquatic organisms R20/21/22 - Harmful by inhalation, in contact with skin and if swallowed. R11 - Highly Flammable |
Safety Description | S26 - In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. S28 - After contact with skin, wash immediately with plenty of soap-suds. S45 - In case of accident or if you feel unwell, seek medical advice immediately (show the label whenever possible.) S61 - Avoid release to the environment. Refer to special instructions / safety data sheets. S28A - S23 - Do not breathe vapour. S16 - Keep away from sources of ignition. |
UN IDs | UN 2587 6.1/PG 2 |
WGK Germany | 3 |
RTECS | DK2625000 |
FLUKA BRAND F CODES | 8 |
TSCA | Yes |
HS Code | 2914 69 80 |
Hazard Class | 6.1 |
Packing Group | II |
Toxicity | LD50 orally in rats: 130 mg/kg (Woodard) |
Raw Materials | Aniline Aniline Sulfuric acid Sulfuric acid Manganese Manganese |
Downstream Products | 2-Chlorohydroquinone etamsylate |
yellow crystals. Has a pungent odor similar to chlorine. No boiling point, sublimation. Its vapor is volatile and partially decomposed. Soluble in hot water, ethanol, ether, alkali. Flammable in case of open flame and high heat. By high thermal sublimation to produce toxic gases. Toxic gases are generated by thermal decomposition. In case of high heat, open flame or contact with oxidant, there is a risk of combustion. By high heat decomposition, emission of irritating smoke.
used as a polymerization inhibitor. For the manufacture of hydroquinone and dye intermediates, rubber antioxidant, acrylonitrile and vinyl acetate polymerization initiator and chlorinating agent.
rat oral LD50: 130mg/kg. There is a strong stimulation. High-concentration exposure irritates mucous membranes, upper respiratory tract, eyes, and skin. Oral administration may be fatal. Be protected. Store in a cool, ventilated warehouse. Keep away from fire and heat source. The packaging is sealed. Should be stored separately from the oxidant, edible chemicals, avoid mixed storage.
aniline is dissolved in dilute sulfuric acid, oxidized by manganese dioxide, separated and purified by steam direct distillation, and then crystallized, dehydrated and dried to obtain the product.
LogP | 0.1-0.3 at 23℃ and pH4.8-5.3 |
(IARC) carcinogen classification | 3 (Vol. 15, Sup 7, 71) 1999 |
NIST chemical information | Information provided by: webbook.nist.gov (external link) |
EPA chemical information | Information provided by: ofmpub.epa.gov (external link) |
Introduction | p-benzoquinone is a quinone organic matter. Pure p-benzoquinone is a bright yellow crystal with a pungent smell similar to chlorine; impure samples are often dimmed due to the presence of quinone hydroquinone (a 1:1 charge transfer complex formed by p-benzoquinone and hydroquinone). P-benzoquinone contains a non-aromatic six-membered ring, which is the oxidation product of hydroquinone (hydroquinone). |
Chemical reaction | The non-aromatic six-membered ring of p-benzoquinone reflects a variety of reactivity: it not only exhibits the properties of ketones (can form oxime), but also exhibits oxidizing properties (the reduction product is hydroquinone), and also exhibits the properties of alkenes (addition reactions can occur, especially typical reactions of α,β-unsaturated ketones. P-benzoquinone is unstable in the presence of strong inorganic acids or strong bases, and reactions such as polycondensation and decomposition occur. |
Application | In organic synthesis, p-benzoquinone is used as a hydrogen recipient (dehydrogenation agent) and oxidant. It can also participate in the Diels-Alder reaction as a dienophile. Derivatives of p-benzoquinone interact with acetic anhydride and sulfuric acid to obtain derivatives of 1,2, 4-phloroglucinol triacetate. This reaction was first described by Thiele in 1898, so it is called Thiele reaction. |
uses | intermediates for dyes and medicines. Manufacture of hydroquinone and rubber antioxidants, acrylonitrile and vinyl acetate polymerization initiators and oxidants. p-benzoquinone can be used to make hydroquinone, as dye and pharmaceutical intermediate, rubber antioxidant, polymerization inhibitor, antioxidant, developer, etc.; in organic synthesis, it is used to Diels-Alder cycloaddition dienophile to form naphthoquinone and 1, 4-phenanthrene dione. It is used for qualitative determination of toxinine, pyridine, azacene, tyrosine and hydroquinone. For the determination of amino acids in the analysis. 99% and 99.5% high purity grades are used for photometric determination of amines. |
production method | aniline is dissolved in dilute sulfuric acid, oxidized by manganese dioxide, separated and purified by steam distillation, crystallized, dehydrated and dried to obtain the finished product. In industrial production, this process is also an intermediate step in the production of hydroquinone. In some occasions, such as reagent production and drug manufacturing, hydroquinone is also oxidized to prepare p-benzoquinone. Raw material consumption quota: aniline 2000kg/t, sulfuric acid (93%)8500kg/t, soft manganese ore powder (manganese 60-65%)9500kg/t. |
category | toxic substances |
toxicity classification | highly toxic |
acute toxicity | oral administration-rat LD50: 130 mg/kg; Oral administration-mouse LDL0: 100 mg/kg |
flammability hazard characteristics | open flame is combustible; heated decomposition; combustion releases stimulating smoke |
storage and transportation characteristics | warehouse ventilation and low temperature drying; Store separately from oxidants and food additives |
fire extinguishing agent | carbon dioxide, foam, sand, mist water. |
occupational standard | TWA 0.4 mg/m3; STEL 1.5 mg/m3 |
auto-ignition temperature | 815 °F |
toxic substance data | information provided by: pubchem.ncbi.nlm.nih.gov (external link) |
immediate life-threatening and health concentration | 100 mg/m3 |