A process can be used for preparing methyl methacrylate (MMA), by direct oxidative esterification of methacrolein. The MMA and polymers produced therefrom feature a very low yellowness index. A workup of the reactor output from the oxidative esterification of methacrolein allows for particularly discolouring by-products to be removed or degraded without significant MMA losses.

Provided is a method of preparing a diester-based material, more particularly, a method of preparing a diester-based material, which is carried out by a continuous preparation process of a diester-based material including a reaction part in which a total of n reaction units from a first reaction unit to an nth reaction unit are connected in series, the reaction unit including a reactor which esterifies dicarboxylic acid and alcohol, including: esterifying dicarboxylic acid and alcohol in a reactor of the first reaction unit to produce a reaction product, and supplying a lower discharge stream including the reaction product to a reaction unit at a rear end through a lower discharge line; and supplying a liquid material through a liquid supply line connected to a lower discharge line of the reactor of the first reaction unit.

Provided is a method of preparing a diester-based material, more particularly, a method of preparing a diester-based material, which is carried out by a continuous preparation process of a diester-based material including a reaction part in which a total of n reaction units from a first reaction unit to an nth reaction unit are connected in series, the reaction unit including a reactor which esterifies dicarboxylic acid and alcohol, including: esterifying dicarboxylic acid and alcohol in a reactor of the first reaction unit to produce a reaction product, and supplying a lower discharge stream including the reaction product to a reaction unit at a rear end through a lower discharge line; and supplying a liquid material through a liquid supply line connected to a lower discharge line of the reactor of the first reaction unit.

Provided is a method of preparing a diester-based material, more particularly, a method of preparing a diester-based material, which is carried out by a continuous preparation process of a diester-based material including a reaction part in which a total of n reaction units from a first reaction unit to an nth reaction unit are connected in series, the reaction unit including a reactor which esterifies dicarboxylic acid and alcohol, including: esterifying dicarboxylic acid and alcohol in a reactor of the first reaction unit to produce a reaction product, and supplying a lower discharge stream including the reaction product to a reaction unit at a rear end through a lower discharge line; and supplying a liquid material through a liquid supply line connected to a lower discharge line of the reactor of the first reaction unit.

The present invention relates to a method of manufacturing a diester-based compound, and, more particularly, to a method of manufacturing a diester-based compound, which is performed using a continuous process including a reaction part in which a total of n reaction units spanning from a first reaction unit to an nth reaction unit are connected in series, wherein each of the reaction units includes a reactor, and the method includes: supplying a feed stream including a dicarboxylic acid and an alcohol into the first reactor; esterifying the feed stream to prepare a reaction product; and supplying a lower discharge stream including the reaction product into the reactor of the rear reaction unit. In this case, a conversion rate of the esterification reaction in the first reactor is controlled in a range of 50 to 80%.

The present invention relates to a method of manufacturing a diester-based compound, and, more particularly, to a method of manufacturing a diester-based compound, which is performed using a continuous process including a reaction part in which a total of n reaction units spanning from a first reaction unit to an nth reaction unit are connected in series, wherein each of the reaction units includes a reactor, and the method includes: supplying a feed stream including a dicarboxylic acid and an alcohol into the first reactor; esterifying the feed stream to prepare a reaction product; and supplying a lower discharge stream including the reaction product into the reactor of the rear reaction unit. In this case, a conversion rate of the esterification reaction in the first reactor is controlled in a range of 50 to 80%.

The present invention relates to a stripping method capable of recovering, by an environmentally friendly method, a high-purity ester-based compound without concern over the oxidation of an ester-based compound from a mixture containing the ester-based compound. The stripping method has advantages of generating no wastewater, enabling equipment costs to be reduced by simplifying the process, removing concern over the oxidation of an ester-based compound during the process, and enabling the reuse of the components recovered in the process.

The present invention relates to a stripping method capable of recovering, by an environmentally friendly method, a high-purity ester-based compound without concern over the oxidation of an ester-based compound from a mixture containing the ester-based compound. The stripping method has advantages of generating no wastewater, enabling equipment costs to be reduced by simplifying the process, removing concern over the oxidation of an ester-based compound during the process, and enabling the reuse of the components recovered in the process.

The present disclosure addresses the problem of providing a method for purifying an acrylic acid ester compound. This problem can be solved by a method for purifying a compound represented by formula (1)

##STR00001##

(wherein R.sup.1 and R.sup.2 are the same as or different and each represent an alkyl group, a fluoroalkyl group, an aryl group optionally having one or more substituent groups, a halogen atom, or a hydrogen atom, R.sup.3 is an alkyl group, a fluoroalkyl group, or an aryl group optionally having one or more substituent groups, and X is a fluoroalkyl group or a halogen atom), the method including step A of distilling composition A containing (a) the compound represented by formula (1), (b) an alcohol, and (c) a salt so as to obtain a concentrate containing the compound represented by formula (1).

The present disclosure addresses the problem of providing a method for purifying an acrylic acid ester compound. This problem can be solved by a method for purifying a compound represented by formula (1)

##STR00001##

(wherein R.sup.1 and R.sup.2 are the same as or different and each represent an alkyl group, a fluoroalkyl group, an aryl group optionally having one or more substituent groups, a halogen atom, or a hydrogen atom, R.sup.3 is an alkyl group, a fluoroalkyl group, or an aryl group optionally having one or more substituent groups, and X is a fluoroalkyl group or a halogen atom), the method including step A of distilling composition A containing (a) the compound represented by formula (1), (b) an alcohol, and (c) a salt so as to obtain a concentrate containing the compound represented by formula (1).