Colorless gas with faint aromatic odor, easy to liquefy. Soluble in alcohol and ether, and also soluble in acetone, benzene, dichloroethane, amyl acetate, furfural, and copper ammonia acetate solution. Insoluble in water.

1) Diels-Alder reaction occurs with electron-deficient dienophilic compounds to produce anthraquinone, whose derivatives are important dye intermediates, fungicides and insecticides. (2) React with maleic anhydride (referred to as maleic anhydride) and then condense to produce tetrahydrophthalic anhydride, which can be used as a curing agent and plasticizer for polyester resin and epoxy resin. Tetrahydrophthalic anhydride is then oxidized with nitric acid to obtain butane tetracarboxylic acid, which is a raw material for making water-soluble paint. Similarly, tetrahydrophthalic anhydride is hydrogenated to produce hexahydrophthalic anhydride, which can be used as a curing agent for epoxy resin. (3) It reacts with sulfur dioxide to generate cyclobutene Chemicalbook sulfone, which is then prepared into an aqueous solution and hydrogenated in the presence of a skeleton nickel catalyst to produce cyclobutene sulfolane, which is a selective solvent for aromatic hydrocarbon extraction. A mixture of sulfolane and diisopropanolamine can be used as a decarbonation gas. (4) The linear telomerization reaction of butadiene is very useful in industry. After linear dimerization, an eight-carbon straight-chain olefin is obtained, which is then hydroformylated and hydrogenated to obtain nonanol, which has important uses in the synthesis of fragrances, surfactants, and lubricant additives. Using cobalt complex as a catalyst, its dimerization, trimerization and tetramerization are all raw materials for synthesizing higher alcohols and macrocyclic musk.