Preparation method of lilial intermediate p-tert-butyl-alpha-methylcinnamaldehyde

Abstract

The invention provides a preparation method of a lilial intermediate p-tert-butyl-alpha-methylcinnamaldehyde. The preparation method comprises the steps: charging, dropwise adding of propionaldehyde,heat preservation reaction, crystallization and aftertreatment. A p-tert-butyl-alpha-methylcinnamaldehyde crystal with the purity being larger than or equal to 99% is obtained, the content of p-tert-butyl-alpha-methylcinnamaldehyde at a middle position is lower than 0.1%, high-quality lilial containing larger than or equal to 99% of para-lilial can be obtained if p-tert-butyl-alpha-methylcinnamaldehyde is directly used for a hydrogenation reaction, and a crystallization mother liquid is used for recycling. The process provided by the invention has the advantages such as multiple recycle of a catalyst, simplicity in operation, low energy consumption, environment friendliness and good product quality.

Description

technical field [0001] The invention belongs to the technical field of fragrance chemistry and fine chemicals, and in particular relates to a preparation method of p-tert-butyl-α-methylcinnamaldehyde, a lilial intermediate. Background technique [0002] Lilialdehyde is a colorless to pale yellow liquid with lily of the valley and lily fragrance. The fragrance is soft, fresh, elegant and long-lasting. Widely used in medium and high-grade cosmetic essences and soap essences, it is less irritating to the skin and stable to alkali. [0003] Lilial is a pure synthetic monomer fragrance, which has not been found in nature yet. The industrial production of lylial started in the 1960s, initially by Givaudan. Since the 1960s, large-scale industrial production has started and developed rapidly. In 1992, the world's production of lyral reached 5,000 tons. At present, the main manufacturers of lilial in the world include BASF, Innospec, Givaudan in Switzerland, and BBA in the United ...

AI Technical Summary

Problems solved by technology

[0006] (1) At the end of the reaction, the catalyst needs to be neutralized with acid. On the one hand, a large amount of alkali is wasted, so that the catalyst cannot be recycled. On the other hand, a large amount of three wastes are produced, which increases the cost of post-treatment

[0007] (2) The condensation product p-tert-butyl-a-methylcinnamaldehyde is a light yellow solid with a melting point of 69°C. It is easy to block the pipeline during distillation and material transfer using a thin-film evaporator, and the operation is difficult; on the other hand, the condensation reaction At the end, the solvent methanol needs to be recovered by distillation, and continuous distillation is required to obtain the target product, which consumes a lot of energy

[0008] (3) Propionaldehyde is prone to self-shrinkage reaction under alkaline conditions, resulting in low selectivity of the target product to tert-butyl-α-methylcinnamaldehyde, low purity, and high waste; the reaction crude product removes meta-tert-butyl The base-α-methylcinnamaldehyde is relatively difficult, and the separation energy consumption is high;

[0009] The content of the finished product of lylial obtained after the further hydrogenation of p-tert-butyl-a-methylcinnamaldehyde obtained by the process, m-lilial = 97%. The data in the examples show that, The lowest content of lylial is 0.7%, and the highest content of lylial is ≥98.1%. Among them, lylial has a certain allergenicity, and the quality of lylial is poor

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