Provided herein is a method for cleaning a wafer having a fine uneven surface pattern that at least partially contains a silicon element using a wafer cleaning device that includes a vinyl chloride resin as a liquid contacting member, the method including retaining a water-repellent protective film-forming chemical in at least a recessed portion of the uneven pattern to form a water-repellent protective film on a surface of the recessed portion, the water-repellent protective film-forming chemical containing: a monoalkoxysilane represented by the following general formula [1],

(R.sup.1).sub.aSi(H).sub.3-a(OR.sup.2)  [1]; a sulfonic acid represented by the following general formula [2],

R.sup.3—S(═O).sub.2OH  [2]; and a diluting solvent, wherein the diluting solvent contains 80 to 100 mass % of alcohol with respect to the total 100 mass % of the diluting solvent.

Provided herein is a method for cleaning a wafer having a fine uneven surface pattern that at least partially contains a silicon element using a wafer cleaning device that includes a vinyl chloride resin as a liquid contacting member, the method including retaining a water-repellent protective film-forming chemical in at least a recessed portion of the uneven pattern to form a water-repellent protective film on a surface of the recessed portion, the water-repellent protective film-forming chemical containing: a monoalkoxysilane represented by the following general formula [1],

(R.sup.1).sub.aSi(H).sub.3-a(OR.sup.2)  [1]; a sulfonic acid represented by the following general formula [2],

R.sup.3—S(═O).sub.2OH  [2]; and a diluting solvent, wherein the diluting solvent contains 80 to 100 mass % of alcohol with respect to the total 100 mass % of the diluting solvent.

The use of hypophosphorous acid as a corrosion inhibitor for esterification reactions of free fatty acids contained in a fatty substance is described, particularly in the presence of an organosulfonic acid. The invention also relates to a method for the esterification of fatty acids.

The use of hypophosphorous acid as a corrosion inhibitor for esterification reactions of free fatty acids contained in a fatty substance is described, particularly in the presence of an organosulfonic acid. The invention also relates to a method for the esterification of fatty acids.

The present application provides methods for the synthesis of intermediates in the synthesis of Safinamide or a pharmaceutically acceptable salt thereof herein Safinamide Mesylate, that is substantially free of impurities.

The present application provides methods for the synthesis of intermediates in the synthesis of Safinamide or a pharmaceutically acceptable salt thereof herein Safinamide Mesylate, that is substantially free of impurities.

The use of hypophosphorous acid as a corrosion inhibitor for esterification reactions of free fatty acids contained in a fatty substance is described, particularly in the presence of an organosulfonic acid. The invention also relates to a method for the esterification of fatty acids.

The present application provides methods for the synthesis of intermediates in the synthesis of Safinamide or a pharmaceutically acceptable salt thereof herein Safinamide Mesylate, that is substantially free of impurities.

The present application provides methods for the synthesis of intermediates in the synthesis of Safinamide or a pharmaceutically acceptable salt thereof herein Safinamide Mesylate, that is substantially free of impurities.

The present invention relates to methods for the production of alkane sulfonic acids, especially methane sulfonic acid, from alkane, especially methane, in which a carbocation, particularly a carbenium ion, is formed, as well as to the use of carbocations, particularly carbenium ions, for the production of alkane sulfonic acids, especially methane sulfonic acid.