Synthesis Method of Acetylacetic Acid Methacrylate Ethylene Glycol Ester

The synthesis methods of acetoacetic acid methyl methacrylate ethylene glycol ester (AAEM) mainly include ester exchange method and ester addition method, as follows:

Ester exchange method: Using hydroxyethyl methacrylate (HEMA) and ethyl acetoacetate (AAA) as raw materials, ester exchange reaction occurs under the action of catalyst to generate AAEM. The reaction equation is: HEMA+AAA → AAEM+ethanol. The specific operation is to mix hydroxyethyl methacrylate and ethyl acetoacetate, add a catalyst (such as lithium doped magnesia zirconia solid superbase catalyst) and a polymerization inhibitor (such as methylhydroquinone), and fully react at 118-125 ℃. During the reaction process, distill the byproduct ethanol while reacting. After the reaction is complete, the catalyst is separated and the resulting liquid product is distilled to remove excess ethyl acetoacetate, which yields AAEM. This method has low cost and minimal environmental pollution, but the reaction temperature is high and there are relatively many side reactions.

Ester addition method: AAEM is synthesized by ester addition reaction using hydroxyethyl methacrylate and divinone as raw materials. This method has high conversion rate, good selectivity, and few by-products, but the raw material diketone is highly toxic and poses certain safety risks and environmental issues. The specific reaction conditions and operating procedures vary depending on the specific process, and usually require controlling a certain temperature and reaction time in the presence of suitable solvents and catalysts for the reaction.

In addition, there is a two-step synthesis process. The first step is to mix the inhibitor, catalyst, solvent, and ethylene glycol, and then add compound A such as methacryloyl chloride dropwise. After heating the reaction, hydroxyethyl methacrylate is obtained by distillation. The second step is to mix the catalyst, polymerization inhibitor, solvent, and hydroxyethyl methacrylate, add compound B such as methyl acetoacetate, heat the reaction, and then distill to obtain ethyl acetoacetate methacrylate (AAEM). This method has good reaction selectivity, high product yield, and no toxic gases are generated during the reaction, making it more environmentally friendly.