Abstract: The invention relates to an esterification unit (150) and esterification process for producing crude methyl methacrylate (MMA) from methacrylamide (MAM), which enable particularly to improve the yield, meaning that the organics spent acids are low; and at the same time, providing crude MMA with rather good quality, meaning that MMA concentration in crude MMA is rather high and preferably from 50 wt % to 80 wt %. According to the invention, the esterification unit comprises esterification reactors (1, . . . , 5 (or 6) set up in a serial way so that there is a counter current flow between gaseous phase and liquid phase, the liquid phase flowing from first reactor (1) of the series to last reactor (5 (or 6)), and the gaseous phase flowing from reactor to first reactor (1).

Abstract: The invention relates to a purification unit (200) which is able to separate crude MMA from light and heavy impurities in order to obtain high quality of MMA, suitable to produce optimal grade polymethylmethacrylate (PMMA). The unit (200) comprises two distillation columns (210, 250) in series, fed with mixture to be distilled in their median part, in order to separate each column in two upper (213, 253) and lower (212, 252) parts, the first distillation column (210) being fed with crude prewashed MMA, and the second distillation column (250) being fed with distilled liquid stream containing MMA, separated from light impurities, issued from bottom of first distillation column (210). The upper part (213) of first distillation column (210) is connected to a lateral extraction system (220), able to minimize MMA content in light impurities flowing upward said first column (210).

Abstract: The invention relates to an esterification unit (150) and esterification process for producing crude methyl methacrylate (MMA) from methacrylamide (MAM), which enable particularly to improve the yield, meaning that the organics spent acids are low; and at the same time, providing crude MMA with rather good quality, meaning that MMA concentration in crude MMA is rather high and preferably from 50 wt % to 80 wt %. According to the invention, the esterification unit comprises esterification reactors (1, . . . , 5 (or 6) set up in a serial way so that there is a counter current flow between gaseous phase and liquid phase, the liquid phase flowing from first reactor (1) of the series to last reactor (5 (or 6)), and the gaseous phase flowing from reactor to first reactor (1).

Abstract: The invention relates to an hydrolysis vessel (200) used during amidification step of acetone cyanohydrin (ACH), in the industrial process for production of a methyl methacrylate (MMA) or methacrylic acid (MAA). The hydrolysis vessel (200) is used for hydrolyzing acetone cyanohydrine with sulfuric acid to produce a mixture comprising ?-sulfatoisobutyramide (SIBAM). It comprises at least one cooling system (212; 244) on its internal annular periphery area and it is divided into at least two stages, preferably three, along its vertical wall, each stage (S1 to S3) comprising a ACH feeding inlet (201, 202, 203). Such vessel allows controlling both homogeneity and temperature of the mixture, and thus obtaining a high yield for the hydrolyzing reaction in very safe conditions.

Abstract: The invention relates to an esterification unit (150) and esterification process for producing crude methyl methacrylate (MMA) from methacrylamide (MAM), which enable particularly to improve the yield, meaning that the organics spent acids are low; and at the same time, providing crude MMA with rather good quality, meaning that MMA concentration in crude MMA is rather high and preferably from 50 wt % to 80 wt %. According to the invention, the esterification unit comprises esterification reactors (1, . . . , 5 (or 6) set up in a serial way so that there is a counter current flow between gaseous phase and liquid phase, the liquid phase flowing from first reactor (1) of the series to last reactor (5 (or 6)), and the gaseous phase flowing from reactor to first reactor (1).

Abstract: The invention relates to an esterification unit (150) and esterification process for producing crude methyl methacrylate (MMA) from methacrylamide (MAM), which enable particularly to improve the yield, meaning that the organics spent acids are low; and at the same time, providing crude MMA with rather good quality, meaning that MMA concentration in crude MMA is rather high and preferably from 50 wt % to 80 wt %. According to the invention, the esterification unit comprises esterification reactors (1, . . . , 5 (or 6) set up in a serial way so that there is a counter current flow between gaseous phase and liquid phase, the liquid phase flowing from first reactor (1) of the series to last reactor (5 (or 6)), and the gaseous phase flowing from reactor to first reactor (1).

Abstract: The invention relates to an hydrolysis vessel (200) used during amidification step of acetone cyanohydrin (ACH), in the industrial process for production of a methyl methacrylate (MMA) or methacrylic acid (MAA). The hydrolysis vessel (200) is used for hydrolyzing acetone cyanohydrine with sulfuric acid to produce a mixture comprising ?-sulfatoisobutyramide (SIBAM). It comprises at least one cooling system (212; 244) on its internal annular periphery area and it is divided into at least two stages, preferably three, along its vertical wall, each stage (S1 to S3) comprising a ACH feeding inlet (201, 202, 203). Such vessel allows controlling both homogeneity and temperature of the mixture, and thus obtaining a high yield for the hydrolyzing reaction in very safe conditions.