P-methoxy cinnamic acid ester preparation method

Abstract

The invention discloses a p-methoxy cinnamic acid ester preparation method and belongs to the field of organic synthesis. The p-methoxy cinnamic acid ester preparation method comprises the steps that 1, p-methoxyaniline and 60-75 wt % of sulfuric acid solution are evenly mixed, 18-25 wt % of sodium fluoborate solution is dropped into the mixed solution at the temperature from 30 DEG C to 50 DEG C; 2, acrylic ester, surfactant and catalysts are added in the solution, and the solution is evenly stirred; 18-21 wt% of sodium nitrite solution is dropped into the solution during the stirring process, all the sodium nitrite solution is dropped in the solution for 30-60 minutes, the inner temperature is controlled within the range from 30 DEG C to 45 DEG C during the dropping process, and the temperature is kept and the reaction continues for 30 to 40 minutes after the dropping is finished; 4, the temperature is increased to 50 DEG C to 60 DEG C, and the reaction is conducted for 1-1.5 hours and then the reaction is over. According to the p-methoxy cinnamic acid ester preparation method, raw materials and the catalysts are low in cost and high in using efficiency, the operation is simple and pollution is little. In addition, an ordinary diazotization reaction needs to be controlled at low temperature, and the temperature for the p-methoxy cinnamic acid ester preparation method during the dizotization process is milder, the corresponding cooling cost is saved, and the p-methoxy cinnamic acid ester preparation method has wider industrialized application prospects.

Description

technical field [0001] The invention belongs to the field of organic synthesis, and in particular relates to a method for preparing p-methoxycinnamate. Background technique [0002] p-Methoxycinnamate is currently the most commonly used sunscreen agent in the world. It has excellent ultraviolet light absorption range, high absorption rate, little skin irritation, good safety, and good solubility to oily raw materials , is a very ideal sunscreen agent, and has good applications in the fields of daily chemicals, plastics, rubber and coatings. There are mainly two existing industrial production processes for p-methoxycinnamate, namely the Perkin process and the Knoevenagel process. The above two processes all use p-methoxybenzaldehyde as the initial raw material, and p-methoxybenzaldehyde belongs to the famous and precious spices, and the price is relatively expensive, which will directly lead to excessively high process costs. At the same time, these processes also have prob...

AI Technical Summary

Problems solved by technology

Both of the above two processes use p-methoxybenzaldehyde as the initial raw material, and p-methoxybenzaldehyde is a rare spice with a high price, which will directly lead to high process costs

At the same time, these processes also have problems such as low total yield, complicated process, and serious wastes; after years of research, scholars from various countries have found relatively cheap raw material p-methoxyaniline, such as US5300675 and EP0553668A2, which are based on p-methoxyaniline p-Methoxycinnamate was successfully prepared using phenylaniline as raw material

However, the precious metal palladium is used as a catalyst in its technical solutions, and its cost is extremely high. Therefore, the problem of catalyst regeneration must be solved in industrial production, so as to improve the recycling rate of the catalyst and reduce the cost of catalyst use, so that it can be industrialized. prospect

Images