Benzoquinone is used as an organic compound with the molecular formula C6H4O2.Pure p-benzoquinone is a bright yellow crystal with a pungent odor similar to chlorine gas;Impurity samples are often dimmed by the presence of quinone hydroquinone, a 1:1 charge transfer complex formed between p-benzoquinone and hydroquinone.Para-benzoquinone contains the non-aromatic six-membered ring, which is the oxidation product of hydroquinone (hydroquinone).This molecule reflects a variety of reactivity: it exhibits both ketone properties (the formation of oximes), oxidative properties (the reduction products are hydroquinones), and alkene properties (addition reactions can occur, especially those typical of α, β-unsaturated ketones).The p-benzoquinone is unstable in the presence of strong inorganic acid or strong base, and condensation polymerization and decomposition reactions occur.
|Other Name||2,5-Cyclohexadiene-1,4-dione;p-benozquinone;Thiophene,5-dibromo;2,5-dibromo thiophene;cyclohexadiene-1,4-dione;|
|Appearance and properties||Yellow Solid|
|Storage conditions||Stored in normal temperature|
Benzoquinone is used as following:
1. Used for the qualitative determination of carnine, pyridine, azalene, tyrosine and hydroquinone.Determination of amino acids.Dehydrogenation agent.Oxidant.Making dyes.
2. Used as a polymer inhibitor.Used for the manufacture of hydroquinone and dye intermediates, rubber antiaging agents, acrylonitrile and vinyl acetate polymerization initiators and chlorination agents.
3. Used as a polymer inhibitor for styrene, vinyl acetate, methyl methacrylate, unsaturated polyester resin and other monomers. Its polymer resistance and heat resistance are better than hydroquinone.It is also an initiator for polymerization of acrylonitrile and vinyl acetate.Also used as natural rubber, synthetic rubber, food and other organic antioxidant.Also used as leather tanning preparation, photographic developer and manufacturing dyes, pharmaceuticals and cosmetics raw materials.
4. It is a commonly used oxidation or dehydrogenation reagent, because it is easily reduced to hydroquinone by other compounds, which can show oxidative activity.In addition, its oxidation potential determines that 1, 4-benzoquinone can selectively oxidize conjugated primary allyl alcohol in the presence of multiple alcohol compounds. For example, cinnamyl alcohol can be selectively oxidized to cinnamaldehyde in the presence of secondary alcohol and benzyl alcohol.
5. Used as dye intermediate, used for determination of amino acids in the analysis.
Benzoquinone was produced by the followings:
1. The aniline is dissolved in dilute sulfuric acid, oxidized by manganese dioxide, separated and purified by steam distillation, crystallized, dehydrated and dried, and the finished product is obtained.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 used as the raw material to produce p-benzoquinone by oxidation.Rraw material consumption quota: aniline 2000kg/t, sulfuric acid (93%)8500kg/t, pyrolusite powder (containing manganese 60-65%)9500kg/t.
2. The 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.
3. Electrochemical oxidation synthesis using triethyl benzylammonium chloride (BNET3NCl) as phase transfer catalyst, benzene as raw material,H2SO
4. As a supporting electrolyte, p-benzoquinone was synthesized by electrochemical oxidation of Na2SO4 on lead dioxide anode.The optimized process conditions are as follows: BNet3NCl content of 0.1%, benzene of 16% or 4%,Na2SO42%, temperature of 40℃, current density of 2.5A/dm2, current efficiency of more than 38%, maximum yield of 63%.