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.

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.

The present invention relates to a process for preparing alpha-hydroxycarboxylic esters proceeding from hydrogen cyanide, wherein the ammonia formed in the step of alcoholysis of the corresponding alpha-hydroxycarboxamide is recycled into a hydrogen cyanide preparation process after a purification step.

The present invention relates to a process for preparing alpha-hydroxycarboxylic esters proceeding from hydrogen cyanide, wherein the ammonia formed in the step of alcoholysis of the corresponding alpha-hydroxycarboxamide is recycled into a hydrogen cyanide preparation process after a purification step.

The present invention relates to a process for preparing alpha-hydroxycarboxylic esters proceeding from hydrogen cyanide, wherein the ammonia formed in the step of alcoholysis of the corresponding alpha-hydroxycarboxamide is recycled into a hydrogen cyanide preparation process after a purification step.

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).

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).

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).

Present invention relates to a process and an installation (100) for the preparation of hydrogen cyanide by the Andrussow process, and more precisely for improving the conditions of mixing the reactant gases before feeding the Andrussow type reactor (60), in order to improve safety, to avoid any risk of explosion and to produce HCN in safe and efficient manner. The installation is configured in such a manner that oxygen is pre-mixed with air with a ratio comprised between 20.95% and 32.5% by volume, preferably between 25% and 30.5% by volume; methane containing gas and ammonia are simultaneously added in the pre-mixture of oxygen-enriched air in such a manner that the volumic ratio of methane to ammonia is comprised between 1.35 and 1.02 depending on the content of oxygen into air; said obtained reactant gases mixture having a temperature comprised between 80 C. and 120 C., preferably between 95 C. and 115 C. for feeding the Andrussow type reactor (60).

Present invention relates to a process and an installation (100) for the preparation of hydrogen cyanide by the Andrussow process, and more precisely for improving the conditions of mixing the reactant gases before feeding the Andrussow type reactor (60), in order to improve safety, to avoid any risk of explosion and to produce HCN in safe and efficient manner. The installation is configured in such a manner that oxygen is pre-mixed with air with a ratio comprised between 20.95% and 32.5% by volume, preferably between 25% and 30.5% by volume; methane containing gas and ammonia are simultaneously added in the pre-mixture of oxygen-enriched air in such a manner that the volumic ratio of methane to ammonia is comprised between 1.35 and 1.02 depending on the content of oxygen into air; said obtained reactant gases mixture having a temperature comprised between 80 C. and 120 C., preferably between 95 C. and 115 C. for feeding the Andrussow type reactor (60).