US 12,240,805 B2
Method for producing 1,4-dimethylnaphthalene
Jianpo Ren, Hebei (CN); Lieyi Ji, Hebei (CN); Junsheng Wang, Hebei (CN); and Zhiqiang Jiang, Hebei (CN)
Assigned to Sinochem Hebei Fuheng Co., Ltd, Hebei (CN); and Sato Planning Co., Ltd, Ibaraki (JP)
Appl. No. 17/928,700
Filed by Sinochem Hebei Fuheng Co., LTD, Hebei (CN); and Sato Planning Co., Ltd, Ibaraki (JP)
PCT Filed Aug. 10, 2021, PCT No. PCT/CN2021/111655
§ 371(c)(1), (2) Date Nov. 30, 2022,
PCT Pub. No. WO2022/257260, PCT Pub. Date Dec. 15, 2022.
Claims priority of application No. 202110633219.5 (CN), filed on Jun. 7, 2021.
Prior Publication US 2024/0228406 A1, Jul. 11, 2024
Int. Cl. C07C 5/41 (2006.01); B01J 21/12 (2006.01)
CPC C07C 5/41 (2013.01) [B01J 21/12 (2013.01); C07C 2521/12 (2013.01); C07C 2531/025 (2013.01)] 2 Claims
 
1. A method for producing 1,4-dimethylnaphthalene, comprising: cyclizing 5-phenyl-2-hexene in the presence of an acid catalyst to prepare crude 1,4-dimethyl-1,2,3,4-tetrahydronaphthalene, dehydrogenizing the crude 1,4-dimethyl-1,2,3,4-tetrahydronaphthalene to obtain a crude 1,4-dimethylnaphthalene, and purifying the crude 1,4-dimethylnaphthalene by distillation, wherein in this production method, the acid catalyst is a sulfonic acid or an amorphous silica-alumina catalyst, and the cyclization reaction takes place in a liquid phase at a temperature of 200° C. or lower to make a concentration of 1,3-dimethyl-1,2,3,4-tetrahydronaphthalene in 1,4-dimethyl-1,2,3,4-tetrahydronaphthalene be 1.0% or less with respect to 1,4-dimethyl-1,2,3,4-tetrahydronaphthalene, and
wherein a concentration of 1,3-dimethylnaphthalene in 1,4-dimethylnaphthalene is 1.0% or less with respect to 1,4-dimethylnaphthalene.