Purification methods and systems for working up a crude vinyl acetate stream containing vinyl acetate monomer, acetic acid, water, ethyl acetate, and other impurities. Crude vinyl acetate streams are purified with an azeotropic distillation tower using a side draw to remove ethyl acetate and water, and a bottom stream to remove acetic acid from the crude vinyl acetate. The methods and systems move the side draw to a location on the azeotropic distillation tower that maintains a constant water concentration in the bottom product of about 4 to about 15 wt. % and forms a vapor side product. A second distillation tower is used to further purify the vapor side product to obtain water, VAM, ethyl acetate and AA. The system provides easier disposal of ethyl acetate, and cleaner water that can be recycled in the reactor or purification sections of a VAM plant and full recovery of AA.

Purification methods and systems for working up a crude vinyl acetate stream containing vinyl acetate monomer, acetic acid, water, ethyl acetate, and other impurities. Crude vinyl acetate streams are purified with an azeotropic distillation tower using a side draw to remove ethyl acetate and water, and a bottom stream to remove acetic acid from the crude vinyl acetate. The methods and systems move the side draw to a location on the azeotropic distillation tower that maintains a constant water concentration in the bottom product of about 4 to about 15 wt. % and forms a vapor side product. A second distillation tower is used to further purify the vapor side product to obtain water, VAM, ethyl acetate and AA. The system provides easier disposal of ethyl acetate, and cleaner water that can be recycled in the reactor or purification sections of a VAM plant and full recovery of AA.

Methods and systems for producing vinyl acetate may use flammability limit (FL) formulas with improved efficiencies at more than one location in the vinyl acetate production process. Herein, FLs can be used at one or more of four portions of the vinyl acetate production process: the reactor, the process-to-process heat exchangers, the carbon dioxide removal system, and the ethylene recovery system. Such FLs are functions of operating conditions and include at least one interaction term that represents the interrelation of two or more of the operating conditions (e.g., temperature, pressure, and component concentration) on the FL.

Methods and systems for producing vinyl acetate may use flammability limit (FL) formulas with improved efficiencies at more than one location in the vinyl acetate production process. Herein, FLs can be used at one or more of four portions of the vinyl acetate production process: the reactor, the process-to-process heat exchangers, the carbon dioxide removal system, and the ethylene recovery system. Such FLs are functions of operating conditions and include at least one interaction term that represents the interrelation of two or more of the operating conditions (e.g., temperature, pressure, and component concentration) on the FL.

Methods and systems for producing vinyl acetate may use flammability limit (FL) formulas with improved efficiencies at more than one location in the vinyl acetate production process. Herein, FLs can be used at one or more of four portions of the vinyl acetate production process: the reactor, the process-to-process heat exchangers, the carbon dioxide removal system, and the ethylene recovery system. Such FLs are functions of operating conditions and include at least one interaction term that represents the interrelation of two or more of the operating conditions (e.g., temperature, pressure, and component concentration) on the FL.

[Problem to be solved] To provide a traceable vinyl acetate, a polymer containing the vinyl acetate, and a vinyl alcohol polymer which is a saponified product of the polymer.

[Solution] Vinyl acetate having a ratio of carbon-14 to total carbon of 1.0×10.sup.−4 or more, a vinyl acetate polymer containing the vinyl acetate as a monomer unit and a vinyl alcohol polymer obtained by saponifying the vinyl acetate polymer.

[Problem to be solved] To provide a traceable vinyl acetate, a polymer containing the vinyl acetate, and a vinyl alcohol polymer which is a saponified product of the polymer.

[Solution] Vinyl acetate having a ratio of carbon-14 to total carbon of 1.0×10.sup.−4 or more, a vinyl acetate polymer containing the vinyl acetate as a monomer unit and a vinyl alcohol polymer obtained by saponifying the vinyl acetate polymer.

Provided are: a gas barrier resin composition having sufficient long-run workability and superior gas barrier properties which compare favorably to those of fossil fuel-derived resins, while containing a biomass-derived raw material; a multilayer structure in which the gas barrier resin is used; and a method for producing such a gas barrier resin composition. The gas barrier resin composition contains at least one type of saponified ethylene-vinyl ester copolymer, wherein of ethylene and a vinyl ester, which are raw materials of the at least one type of saponified ethylene-vinyl ester copolymer, a part is derived from biomass, and a remainder is derived from a fossil fuel.

Provided are: a gas barrier resin composition having sufficient long-run workability and superior gas barrier properties which compare favorably to those of fossil fuel-derived resins, while containing a biomass-derived raw material; a multilayer structure in which the gas barrier resin is used; and a method for producing such a gas barrier resin composition. The gas barrier resin composition contains at least one type of saponified ethylene-vinyl ester copolymer, wherein of ethylene and a vinyl ester, which are raw materials of the at least one type of saponified ethylene-vinyl ester copolymer, a part is derived from biomass, and a remainder is derived from a fossil fuel.

Methods and systems for producing vinyl acetate may use flammability limit (FL) formulas with improved efficiencies at more than one location in the vinyl acetate production process. Herein, FLs can be used at one or more of four portions of the vinyl acetate production process: the reactor, the process-to-process heat exchangers, the carbon dioxide removal system, and the ethylene recovery system. Such FLs are functions of operating conditions and include at least one interaction term that represents the interrelation of two or more of the operating conditions (e.g., temperature, pressure, and component concentration) on the FL.