Preparation method of lilial

Abstract

The invention relates to a preparation method of lilial. The preparation method of lilial comprises the following steps that p-tert.-butyl-benzaldehyde, methanol and caustic soda flake solutions having different concentrations are added into a reactor; n-propanal is dropwisely added into the reactor at a certain temperature and undergoes a condensation reaction and after addition of n-propanal isfinished, the condensation reaction lasts for 0.5 to 2 hours under the condition of heat preservation; acidic materials are added into the reaction system to adjust a pH value and to stop the condensation reaction; after the condensation reaction is finished, methanol is recovered by distillation and a condensation product p-tert.-butyl-alpha-methyl phenyl acrolein is obtained by film evaporator distillation; methanol, p-tert.-butyl-alpha-methyl phenyl acrolein and a hydrogenation catalyst are added into a hydrogenation reactor; hydrogen is fed into the hydrogenation reactor and the mixture in the hydrogenation reactor undergoes a hydrogen reaction; and after the hydrogen reaction is finished, the reaction products are subjected to filter pressing, solvent removal and rectification so that a finished product lilial is obtained. Lilial obtained by the preparation method is a colorless and transparent liquid, and has a refractive index (nd20) of 1.504 to 1.506, the specific gravity (25 DEG C, mg / mL) of 0.942 to 0.946, an acid value (mgKOH / g) of 2.0(max.), the GC content (determined by an area normalization method) of m-LLY less than 2.0%, p-LLY great than or equal to 97.0% and m-LLY+p-LLY great than or equal to 98.0%, and the moisture content less than or equal to 0.25%.

Description

technical field [0001] The invention relates to a method for preparing an organic intermediate, in particular to a method for preparing lyral, and belongs to the technical field of fragrance and essence chemical industry. Background technique [0002] Lilial (p-tert.-butyl-α-methylhydrocinamic aldehyde, referred to as: lilial) is one of the varieties with the largest output in synthetic spices. It is liquid under normal conditions and has a boiling point of 279 ° C. The fragrance of flowers such as eargrass is pure, soft and elegant, and is very popular among perfumers. Widely used in medium and high-end cosmetic essences and soap essences, usually used to blend lily of the valley, frangipani, oriental and floral essences. This kind of spices plays an important role in the deployment of new fragrance flavors. At present, there are no less than 2000 kinds of commonly used varieties. [0003] Industrial production of lyral began in the late 1960s, and the main manufacturer i...

AI Technical Summary

Problems solved by technology

However, these methods do not describe the source of p-tert-butyl-α-methylphenylacrolein or its condensation preparation process. In fact, the condensation reaction is sensitive to temperature. If the control is not good, the by-products will affect the subsequent selection. Adverse effects of sexual hydrogenation

[0005] At present, the lylial used in the domestic fragrance industry is still mainly imported. The process pollution of the domestically produced lylial is heavy, the product quality is poor, and the aroma and purity are difficult to meet the standards of foreign imports.