An object of the present invention is to provide a method for manufacturing methionine capable of achieving an improvement in ammonia removal efficiency. The manufacturing method of the present invention comprises a removal step of supplying a liquid containing a methionine salt, which is obtained by reacting 3-methylmercaptopropionaldehyde and hydrocyanic acid, or a compound obtained by reacting 3-methylmercaptopropionaldehyde and hydrocyanic acid, with carbon dioxide and ammonia to obtain a liquid containing 5-(2-methylmercaptoethyl)hydantoin and then hydrolyzing the 5-(2-methylmercaptoethyl)hydantoin, to a diffusion tower from an upper portion thereof while supplying a stripping gas to the diffusion tower from a lower portion thereof to remove ammonia contained in the liquid through stripping, and the stripping gas contains a process gas generated in a process of manufacturing methionine.

An object of the present invention is to provide a method for manufacturing methionine capable of achieving an improvement in ammonia removal efficiency. The manufacturing method of the present invention comprises a removal step of supplying a liquid containing a methionine salt, which is obtained by reacting 3-methylmercaptopropionaldehyde and hydrocyanic acid, or a compound obtained by reacting 3-methylmercaptopropionaldehyde and hydrocyanic acid, with carbon dioxide and ammonia to obtain a liquid containing 5-(2-methylmercaptoethyl)hydantoin and then hydrolyzing the 5-(2-methylmercaptoethyl)hydantoin, to a diffusion tower from an upper portion thereof while supplying a stripping gas to the diffusion tower from a lower portion thereof to remove ammonia contained in the liquid through stripping, and the stripping gas contains a process gas generated in a process of manufacturing methionine.

An object of the present invention is to provide a method for manufacturing methionine capable of achieving an improvement in ammonia removal efficiency. The manufacturing method of the present invention comprises a removal step of supplying a liquid containing a methionine salt, which is obtained by reacting 3-methylmercaptopropionaldehyde and hydrocyanic acid, or a compound obtained by reacting 3-methylmercaptopropionaldehyde and hydrocyanic acid, with carbon dioxide and ammonia to obtain a liquid containing 5-(2-methylmercaptoethyl)hydantoin and then hydrolyzing the 5-(2-methylmercaptoethyl)hydantoin, to a diffusion tower from an upper portion thereof while supplying a stripping gas to the diffusion tower from a lower portion thereof to remove ammonia contained in the liquid through stripping, and the stripping gas contains a process gas generated in a process of manufacturing methionine.

The following invention regards a process of demethylating a methyl ester of methionine or its hydroxy analog and producing methane thiol as a side-product. The methionine and its hydroxy analog are suitable as an animal feed additive and as a food additive. The methane thiol may be consumed in a hydrothiolation step such as in a step of preparing the methyl ester of methionine or its hydroxy analog from methyl vinyl glycolate.

The following invention regards a process of demethylating a methyl ester of methionine or its hydroxy analog and producing methane thiol as a side-product. The methionine and its hydroxy analog are suitable as an animal feed additive and as a food additive. The methane thiol may be consumed in a hydrothiolation step such as in a step of preparing the methyl ester of methionine or its hydroxy analog from methyl vinyl glycolate.

The following invention regards a process of demethylating a methyl ester of methionine or its hydroxy analog and producing methane thiol as a side-product. The methionine and its hydroxy analog are suitable as an animal feed additive and as a food additive. The methane thiol may be consumed in a hydrothiolation step such as in a step of preparing the methyl ester of methionine or its hydroxy analog from methyl vinyl glycolate.

Provided is a carbon quantum dot having a graphite core and a surface including components, such as compounds derived from formula (I) and halogens, and having a positive charge for antibacterial purposes. Also provided are methods for preparing a carbon quantum dot and a composition containing the same.

Provided is a carbon quantum dot having a graphite core and a surface including components, such as compounds derived from formula (I) and halogens, and having a positive charge for antibacterial purposes. Also provided are methods for preparing a carbon quantum dot and a composition containing the same.

A process produces a mono vinyl thioether by reacting acetylene with a compound containing one thiol group and one hydroxy group, referred to as a thiol-hydroxy compound, where the reaction is performed at a pressure below 2 bars.

A process produces a mono vinyl thioether by reacting acetylene with a compound containing one thiol group and one hydroxy group, referred to as a thiol-hydroxy compound, where the reaction is performed at a pressure below 2 bars.