There is described a method of reducing polymer tar build-up in the production of methyl methacrylate and/or methacrylic acid by the acetone cyanohydrin process. In the method a stabiliser is contacted with the amide stage reaction medium. The stabiliser includes a hydrocarbon moiety capable of donating a labile hydrogen atom to a methacrylamide derivative capable of reaction with said labile hydrogen atom under the conditions in the said medium. The method herein is especially useful for the continuous production of methyl methacrylate and/or methacrylic acid.

The subject of the present invention is a process for producing a sulfonic acid which is sparingly corrosive, or even non-corrosive, with respect to stainless steels, said process comprising at least the steps of adding at least one nitrite to a sulfonic acid, curing, with stirring, with sparging of the mixture and recovering the low-corrosion sulfonic acid obtained. The invention also relates to the low-corrosion sulfonic acid obtained according to the process of the invention, and also to the use thereof as low-corrosion sulfonic acid.

The subject of the present invention is a process for producing a sulfonic acid which is sparingly corrosive, or even non-corrosive, with respect to stainless steels, said process comprising at least the steps of adding at least one nitrite to a sulfonic acid, curing, with stirring, with sparging of the mixture and recovering the low-corrosion sulfonic acid obtained. The invention also relates to the low-corrosion sulfonic acid obtained according to the process of the invention, and also to the use thereof as low-corrosion sulfonic acid.

The subject of the present invention is a process for producing a sulfonic acid which is sparingly corrosive, or even non-corrosive, with respect to stainless steels, said process comprising at least the steps of adding at least one nitrite to a sulfonic acid, curing, with stirring, with sparging of the mixture and recovering the low-corrosion sulfonic acid obtained. The invention also relates to the low-corrosion sulfonic acid obtained according to the process of the invention, and also to the use thereof as low-corrosion sulfonic acid.

Provided are a novel water-soluble diacetylene monomer, a composition for photolithography including the novel water-soluble diacetylene monomer and a conductive polymer, and a method of forming micropatterns using the composition. The water-soluble diacetylene monomer may not aggregate even when mixed with a water-soluble conductive polymer. Accordingly, a uniform composition for photolithography can be prepared by mixing a water-soluble conductive polymer with the diacetylene monomer, and micropatterns can be formed using the composition. More particularly, when the composition is formed into a thin film and then is irradiated with light, only light-irradiated portions of the diacetylene monomer are selectively crosslinked due to photopolymerization, thereby resulting in insoluble negative-type micropatterns.

Provided are a novel water-soluble diacetylene monomer, a composition for photolithography including the novel water-soluble diacetylene monomer and a conductive polymer, and a method of forming micropatterns using the composition. The water-soluble diacetylene monomer may not aggregate even when mixed with a water-soluble conductive polymer. Accordingly, a uniform composition for photolithography can be prepared by mixing a water-soluble conductive polymer with the diacetylene monomer, and micropatterns can be formed using the composition. More particularly, when the composition is formed into a thin film and then is irradiated with light, only light-irradiated portions of the diacetylene monomer are selectively crosslinked due to photopolymerization, thereby resulting in insoluble negative-type micropatterns.

The subject of the present invention is a weakly corrosive and weakly coloured sulfonic acid, with an APHA colour index of less than 20, comprising chlorides and nitrites in a chloride/sulfonic acid molar ratio of between 1 ppm and 200 ppm, and a nitrite/sulfonic acid molar ratio of between 200 ppm and 6000 ppm, limits inclusive.

The subject of the present invention is a weakly corrosive and weakly coloured sulfonic acid, with an APHA colour index of less than 20, comprising chlorides and nitrites in a chloride/sulfonic acid molar ratio of between 1 ppm and 200 ppm, and a nitrite/sulfonic acid molar ratio of between 200 ppm and 6000 ppm, limits inclusive.

The subject of the present invention is a weakly corrosive and weakly coloured sulfonic acid, with an APHA colour index of less than 20, comprising chlorides and nitrites in a chloride/sulfonic acid molar ratio of between 1 ppm and 200 ppm, and a nitrite/sulfonic acid molar ratio of between 200 ppm and 6000 ppm, limits inclusive.

The present invention relates to a method of carrying out an organic reaction in aqueous solution in the presence of a hydroxyalkyl(alkyl)cellulose or an alkylcellulose.