- Hexamethyltetralin Preparations Effect of Methyltrioctylammonium Chloride on Solvent/Olefin Interdependency
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The use of quaternary ammonium salts as co-catalysts in the AlCl3 catalyzed cyclialkylation of p-cymene, 2-chloro-2methylpropane, and 3, 3-dimethylbutene-1 is reported.The addition of co-catalyst, in solvents which normally give low yields of 1,1,3,4,4,6-hexamethyl-1,2,3,4-tetrahydronaphthalene with 3,3-dimethylbutene-1, improves product yields, comparable with the best published 3,3-dimethylbutene-1 methodology.Addition of co-catalyst permits the use of more environmentally acceptable solvent systems than those in existing syntheses of the desired tetralin.The yield improvement is rationalized on the basis of improved reaction homogeneity, facile cleavage of Al2Cl6 by Cl- ion, and increased effective solvent polarity, promoted by addition of the quaternary ammonium salt co-catalysts.Addition of quat co-catalysts to 3,3-dimethylbutene-1 based cyclialkylation systems did not increase rate, catalyst homogeneity or yield relative to a control (dichloromethane solvent).This suggests that the chlorinated hydrocarbon solvents normally used in this technology provide functions similar to that of quats in 2,3-dimethylbutene-1 based technology.These functions include the abilities to enhance AlCl3 solubility, increase the polarity of the reaction medium, and provide facile scission of Al2Cl6 to a more active catalytic species.In reactions where 2,3-dimethylbutene-1 is substituted for 3,3-dimethylbutene-1, addition of co-catalyst improves reaction rate, catalyst homogeneity, and yield reproducibility in non-polar solvents when compared to the best published, 2,3-dimethylbutene-1 methodology.
- Frank, Walter C.,Miller, Donna M.
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- Method for continuously producing 6-acetyl-1,1,2,4,4,7-hexamethyltetralin intermediate HMT by micro-reactor system
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The invention discloses a method for continuously producing a 6-acetyl-1,1,2,4,4,7-hexamethyltetralin intermediate HMT by a micro-reactor system, which comprises the following steps: uniformly mixinga catalyst with a weak polar solvent and a strong polar solvent to obtain a catalyst phase; then mixing 2, 3-dimethyl-1-butene, tert-butyl chloride and p-cymene to obtain a mixture which is used as araw material phase; pre-cooling the two strands of materials, introducing the pre-cooled materials and nitrogen into a cross-shaped micro-mixer for mixing, and enabling the mixture to enter a reactionsection for reaction; introducing the reaction product and an ice hydrochloric acid solution into a T-shaped micro-channel for quenching; and finally, carrying out layering, rectification, recrystallization and drying to obtain the 6-acetyl-1,1,2,4,4,7-hexamethyltetralin intermediate HMT. According to the method, by means of efficient heat transfer capacity of gas-liquid two-phase flow and gas-liquid-liquid three-phase flow in the micro-reactor, a large amount of heat generated in the reaction and quenching processes is rapidly removed, and the problems of low product yield and high risk caused by large temperature rise of the reaction are avoided. Besides, the adopted continuous process can greatly improve the productivity, effectively solves the defects in the existing HMT production process, and realizes green and safe production.
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Paragraph 0009; 0021-0051
(2020/09/12)
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- Synthesis method of 1, 1, 3, 5-tetramethyl-3-isopropyl hydrindene
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The invention relates to a synthetic method of 1, 1, 3, 5-tetramethyl-3-isopropyl hydrindene. The synthetic method specifically comprises the following steps: S1, uniformly mixing p-cymene, chlorotert-butane and 2, 3-dimethyl-1-butene, dropwise adding an obtained mixed solution into a reaction kettle filled with cyclohexane and aluminum trichloride, stirring for reaction, washing with water and alkali for elution, and rectifying to remove p-cymene, so as to obtain a 1, 1, 3, 4, 4, 6-hexamethyltetrahydronaphthalene crude product; S2, transferring the 1, 1, 3, 4, 4, 6-hexamethyl tetrahydronaphthalene crude product obtained in the step S1 into an isomerization kettle, then adding dichloroethane and aluminum trichloride, and carrying out stirring, heating and reflux reaction; S3, washing a product obtained after the isomerization reaction with water and alkali until the product is neutral, desolventizing to remove dichloroethane, transferring an obtained desolventized 1, 1, 3, 5-tetramethyl-3-isopropyl hydrindene crude product into a crystallization kettle, adding a crystallization solvent, and recrystallizing for multiple times to obtain the 1, 1, 3, 5-tetramethyl-3-isopropyl hydrindene. According to the synthetic method of the 1, 1, 3, 5-tetramethyl-3-isopropyl hydrindene, provided by the invention, the yield of a target product is improved, and the purification difficulty is reduced.
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Paragraph 0022-0024; 0027-0028; 0031-0032
(2020/02/14)
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- Method for synthesizing 1,1,3,4,4,6-hexamethyl tetrahydronaphthalene
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The invention provides a method for synthesizing 1,1,3,4,4,6-hexamethyl tetrahydronaphthalene. The method comprises a dropping reaction; according to the dropping reaction, cymene, 2,3-dimethyl-1-butene and a hydrogen absorbent are mixed and dropwise added into a mixture of a catalyst and a solvent; the product yield is up to 80% or more than 80%; on the premise of ensuring the yield and improvingthe yield compared with a traditional process, recycling and reuse of the catalyst are realized, and the problems of large discharge of waste water and difficulty in treating the waste water and waste salt caused by use of anhydrous aluminum trichloride in large doses are solved; and the method has the advantages of low dosage, high activity, no pollution, catalyst recovery and reuse and the like.
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Paragraph 0031-0060
(2019/03/30)
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- HMT continuous synthesis apparatus and method
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The present invention provides an HMT continuous synthesis apparatus and method. The method comprises: taking p-cymene, 2,3-dimethyl-1-butylene, tert-butylchloride cyclohexane as raw materials to prepare a liquid mixture; stirring the mixture uniformly and then placing the mixture into a tubular reactor containing aluminium trichloride; obtaining an HMT reaction liquid in the tubular reactor; carrying out heat insulation while stirring in a transfer kettle and then overflowing the liquid into a hydrolysis kettle; after water washing and alkaline washing, obtaining an HMT crude product by rectification; and obtaining HMT with high purity degree by recrystallization. According to the method provided by the present invention, the process safety is good, the reaction conditions are easy to control, and the product quality is stable, so that HMT continuous large-scale production can be achieved.
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Paragraph 0035; 0036
(2016/10/10)
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- Preparation of 1,1,3,4,4,6-hexamethyl-1,2,3,4-tetra-hydronaphthalene
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A process for preparing 1,1,3,4,4,6-hexamethyl-1,2,3,4-tetrahydronaphthalene of the formula I STR1 comprises reacting p-cymene of the formula II STR2 with a hexene of the formula IIIa, IIIb and/or IIIc STR3 in the presence of a catalytic amount of aluminum halide and a catalytic amount of a triphenylmethyl compound of the formula IV STR4 wherein R1, R2 and R3 are each, independently of one another, hydrogen, C1 -C4 -alkyl, nitro or halogen and X is hydrogen or halogen.
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- Process for preparing polyalkyl tetrahydronaphthalenes
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A process is disclosed for the production of polyalkyl tetrahydronaphthalenes is disclosed wherein a cyclialkylation reaction between an olefinic compound of the general Formula STR1 wherein R4, R5, and R6 are independently defined and each represents a substituent which does not substantially interfere with a Friedel-Crafts type reaction and where R5 and R6 are other than H, and a substituted benzene compound is carried out in the presence of a hydride abstracting reagent, an alkyl halide or hydrogen halide, a Lewis acid, and, optionally, a phase transfer agent. In some embodiments, the subject process is specifically carried out in the absence of elemental iodine. The subject process produces the desired compounds in a surprisingly high yield, with a surprisingly high selectivity to the desired product, and at a relatively high rate of reaction, using better, more convenient, or less expensive process methodology than many processes known heretofore.
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- Process for preparing polyalkyl tetrahydronaphthalenes
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A process is disclosed for the production of polyalkyl tetrahydronaphthalenes wherein a cyclialkylation reaction between an olefinic compound of the general formula STR1 and a substituted benzene compound is carried out in the presence of a hydride abstracting reagent, a Lewis acid, and, optionally, a phase transfer agent. In some embodiments, the subject process is specifically carried out in the absence of elemental iodine. The subject process, which may be practiced in an unhalogenated hydrocarbon solvent, produces the desired compounds in a surprisingly high yield, with a surprisingly high selectivity to the desired product, and at a relatively high rate of reaction, using better, more convenient or less expensive process methodology than many processes known heretofore.
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- Tetrahydronaphthalene derivatives and their production
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Tetrahydronaphthalene derivatives of the formula: STR1 wherein either one of R1 and R2 is hydrogen, C1 -C4 alkyl or C1 -C4 alkoxy and the other is acetyl and R3 is hydrogen or methyl in a racemic or optically active form, which are useful as perfumes or intermediates for production of perfumes, are prepared from an R4 -benzene and pyrocine through the intermediary compounds of the formula: STR2 wherein R4 is hydrogen, C1 -C4 alkyl or C1 -C4 alkoxy present at either one of 6- and 7-positions and A is hydrogen, carboxyl, C2 -C5 alkoxycarbonyl, halogen, methyl, hydroxymethyl or halomethyl.
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- Process for preparing hexamethyltetrahydronaphthalenes
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1,1,3,4,4,6-Hexamethyl-1,2,3,4-tetrahydronaphthalene (HMT), which is an intermediate for the production of acetyl HMT valuable in the art of perfumery because of its musk-like odor properties, is produced with industrial advantages by reacting p-cymene with 2,3-dimethylbutene using a catalytic amount of an anhydrous aluminum halide in the presence of at least one member selected from secondary alkyl halides, tertiary alkyl halides, propargyl halides and allyl halides; and 7-acetyl HMT is obtained by acetylation of the above-obtained HMT.
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