Method for preparing 1,3,4,6-hexamethyl-1,2,4-tetrahydronaphthalene by continuous reaction under catalysis of ionic liquid
A technology of hexamethylnaphthalene and ionic liquid, applied in the field of continuous reaction preparation of hexamethyltetralin under ionic liquid catalysis, can solve the problems of low total yield, long synthesis route, harsh reaction conditions, etc., and achieves improved automation, The effect of stable product quality and excellent regeneration performance
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Embodiment 1
[0024] Under the protection of nitrogen, mix 175.5kg of chloro-n-butane and 147.6kg of N-methylimidazole into the autoclave, reflux for 48 hours at 85℃~105℃, cool and stand for stratification; pour to remove the upper layer Unreacted chloro-n-butane was extracted 3 times with 500L ethyl acetate; then 100L equal volume of acetonitrile-ethyl acetate mixture was added, shaken, frozen at -20°C for 12 hours, and the upper layer liquid was poured to obtain white The crystalline product (crude product), the crude product was vacuum dried at 90°C for 6 hours to obtain 298.9 kg of chloro-1-alkyl-3-methylimidazole ([C 4 H 9 min]Cl).
[0025] Under the protection of nitrogen, 179.8kg of anhydrous aluminum trichloride accurately measured is slowly added to 117.7kg of chloro-1-alkyl-3-methylimidazole ([C 4 H 9 min]Cl) and stirring, the reaction releases a lot of heat. To prevent the temperature of the reaction system from being too high, the preparation process needs to be carried out in a coo...
Embodiment 2
[0027] Under the protection of nitrogen, mix 185kg of bromo-n-butane and 147.6kg of N-methylimidazole into the reactor, replace with nitrogen three times and seal it, keep it at 85℃~105℃ for 30 hours, and obtain a colorless after cooling Alkyl bromide; precipitated with ethyl acetate, recrystallized with suction, washed with ethyl acetate, and dried in vacuo to obtain 287 kg of bromo-1-alkyl-3-methylimidazole ([C 4 H 9 min]Br).
[0028] Under the protection of nitrogen, 183kg of anhydrous iron trichloride accurately measured is slowly added to 120.5kg of bromo-1-alkyl-3-methylimidazole ([C 4 H 9 min]Br), and stirring, the reaction emits a lot of heat. In order to prevent the temperature of the reaction system from being too high, the preparation process needs to be carried out in a cooling kettle with a refrigerant. After the two substances are mixed and become transparent, the invention is obtained. Ionic liquid catalyst used.
[0029] 2. Preparation of hexamethyltetralin
Embodiment 3
[0031] Using the ionic liquid prepared in Example 1 as the catalyst, cyclohexane as the solvent, p-cymene and 3,3-dimethyl-1-butene as raw materials, the alkane was carried out in the presence of the hydrogen transfer reagent tert-butyl bromide. Alkylation reaction; the reaction temperature of the alkylation reaction is -30°C, and the reaction pressure is 1.0×10 3 Pa, the mass ratio of cumene to 3,3-dimethyl-1-butene is 1:1, the mass ratio of cumene to cyclohexane is 1:1, the hydrogen transfer reagent tert-butyl bromide The mass ratio to 3,3-dimethyl-1-butene is 0.5:1.
[0032] The specific process is: using a metering pump, pour p-cymene, cyclohexane, 3,3-dimethyl-1-butene, tert-butyl bromide and the preparation in Example 1 into the static mixer according to the proportions. The ionic liquid catalyst, in which the static mixer has a total length of 3000mm, an inner diameter of 60mm, and contains 50 units of Kenics spirals (left and right rotation alternately, twisted 180°), and...
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