Benzyl alcohol is one of the simplest aromatic alcohols and can be considered as phenyl substituted methanol. Most of them are found in essential oils in essential oils, such as jasmine oil, hyacinth oil, and Peruvian balsam.
Application of benzyl alcohol
Benzyl alcohol is a very useful fixative. It is an indispensable spice in the blending of jasmine, scented scent, and ylang. For the preparation of soap; daily makeup fragrance. However, benzyl alcohol can be naturally oxidized slowly, and a part of it produces benzaldehyde and benzyl ether, so that the commercially available products often have an almond flavor, so it is not suitable for long-term storage. Benzyl alcohol is widely used in the production of industrial chemicals. Used as coating solvent; photographic developer; polyvinyl chloride stabilizer; medicine; synthetic resin solvent; a solvent of vitamin b injection; preservative of ointment or liquid. It can be used as nylon yarn; desiccant of fiber and plastic film, dye; cellulose ester; a solvent of casein, intermediate for preparing benzyl ester or ether. At the same time, it is widely used in pen making (ball pen oil); paint solvent and so on. Benzyl alcohol is a limited preservative in the cosmetic component, and the maximum amount is 1%.
Benzyl alcohol is a flavoring that is now temporarily allowed. It can also be used as a deodorant or a grease solvent. As a spice, it is mainly used to prepare flavors such as berries and nuts. Used in the preparation of floral oils and pharmaceuticals, etc., also as a solvent and a fixative for perfumes; as a solvent, plasticizer, preservative, and in the manufacture of perfumes, soaps, pharmaceuticals, dyes, and the like.
Method for producing benzyl alcohol
Benzyl chloride hydrolysis
It is obtained by heating and hydrolyzing benzyl chloride as a raw material under the catalysis of alkali. Specification of perfume grade benzyl alcohol (QB792-81): relative density of 1.041-1.046, refractive index of 1.538-1.541, boiling range of 203-206 °C distillate of more than 95%, solubility of all dissolved in 30 times of volume of distilled water, including The amount of alcohol is ≥98%, and the chlorine test (NF) is a side reaction. Raw material consumption quota: 1600kg/t benzyl chloride; 1000kg/t soda ash.
Under the action of a basic catalyst, toluene is oxidized to prepare benzyl alcohol. Considering that benzyl alcohol is difficult to separate from the reaction products acetic acid, benzyl acetate, and water, it is under the action of a specific catalyst iodized styrene-divinylbenzene. , cyclic reaction; and benzyl acetate, methanol can also be transesterified, after separation and purification, can obtain high purity benzyl alcohol.
Synthesis of benzyl alcohol from benzene and formaldehyde
Using β-cyclodextrin as the precursor, first reacting with maleic anhydride to synthesize bis(6-oxo-butenedioic acid monoester) β-cyclodextrin (abbreviated E1), and then modifying E1 with chloroacetic acid to obtain double [ 6-Oxo-(3-deoxycitrate monoester)] β-cyclodextrin (abbreviated as E2), which is then used to catalyze the reaction of benzene with formaldehyde to form benzyl alcohol using E1 or E2 as a catalyst.
Preparation of benzyl alcohol by hydrolysis of benzyl ester
The benzyl alcohol is prepared by liquid phase hydrolysis at a temperature of 150-320 ° C using benzyl formate, benzyl propionate, benzyl acetate or benzyl benzoate as raw materials. After the hydrolysis, the reaction mixture is cooled at a temperature of 80-180 ° C, layered, and the organic phase is separated to obtain benzyl alcohol having a purity of more than 98%, and the conversion rate is more than 98%.