Preparation Of Esters Meta-Carboxy Benzoyllactate And Investigation Of Their Initiating Polymerization Of Acrylics

Free-radical initiator is a key research in the field of polymer science, and it is the most widely used in the synthetic polymer materials. A new kind of initiators with easter structure as following: have been developed in our laboratory, one of them, ethyl benzoyllactate can initiate ethyl acrylate polymerization, but there are some disadvantages such as low initiating efficiency and just useful for the solution polymrziaiton using organic diluents. In order to develop an environmentally friendly initiator,-COOH group was introduced into the structure of ethyl benzoyllactate, and two new compounds, ethyl3-carboxybenzoyl lactate and3-carboxybenzoyl lactic acid were synthesized and characterized by1H-NMR, IR and MS.To test their initiating ability, polymerizations with and with the compounds were carried out. The yield of the polymers was calculated by weighting method, Number-average molecular weight (Mn) and molecular weight distribution (MWD) of the polymers was estimated by GPC. At different temperature,1,4-Dioxane as the solvent, polymerization of ethyl acrylate was carried out, no polymer was obtained in the presence or absenece of ethyl3-carboxybenzoyl lactate below60℃. At temperature ranged from60℃to66℃, the polymerization was negligible without ethyl3-carboxybenzoyl lactate, however good yield was obtained in the presence of ethyl3-carboxybenzoyl lactate. Above66℃, thermal polymerization was observed, but much higher yield was in the presence of ethyl3-carboxybenzoyl lactate. The results indicated that ethyl3-carboxybenzoyl lactate certainly initiated the polymerization of ethyl acrylate. The same results were obtained with ethyl3-carboxybenzoyl lactate sodium salt and3-carboxybenzoyl lactic acid sodium salt in the aqueous solution polymerization of acryl acid. Anyhow, no polymer was obtained in the presence or absenece of ethyl3-carboxybenzoyl lactate sodium salt, and little polymer was gained in the blank group only at much higher temperature. At temperature ranged from60℃to80℃.3-carboxybenzoyl lactic acid sodium salt ignited the polymerization, and good yield was gotten. However, no polymerization occurred in the absence of3-carboxybenzoyl lactic acid sodium salt. So this paper finally proved that ethyl3-carboxybenzoyl lactate was a good oil-soluble initiator, but its sodium salt had no initiating ability or extremely low initiating activity in the aqueous solution polymerization; 3-carboxybenzoyl lactic acid sodium salt was a good water-soluble intiator with well-initiating.The effects of temperature, time, monomer concentration and initiator concentration on the polymerization were also investigated. The experiment results showed that with the increase of temperature, time, monomer concentration and initiator concentration, polymerization yield did increase; and Mn decreased with increasing temperature and initiator concentration, but increased with the increase of monomer concentration, however Mn remained unchanged with polymerization time. The polymerization phenomenon showed the chain polymerization characteristics.