FIELD: chemistry.SUBSTANCE: invention relates to use of at least one protonic acid selected from inorganic acids and organic carboxylic acids to stabilise diesters of dicarbonic acid against chemical and thermal decomposition, wherein the protonic acids are used in amount of 0.01-100000 ppm with respect to dialkyl esters of dicarbonic acid or mixture thereof. The invention also relates to a mixture for preserving food products, beverages and materials, which contains one or more diesters of dicarbonic acid of general formula (I), in which R1 and R2 independently denote a straight or branched alkyl with 1-8 carbon atoms, and one or more protonic acids selected from inorganic acids and saturated and mono- or multi-unsaturated aliphatic mono-, di- and polycarboxylic acids, as well as hydroxycarboxylic acids, amino acids, aldehyde acids and keto acids, used in amount of 0.01-100000 ppm with respect to dialkyl ester of dicarbonic acid or mixture thereof； to use of said mixture to preserve food products, beverages and materials and to a method for distillation purification of dialkyl esters of dicarbonic acid, in which one or more dialkyl esters of dicarbonic acid of general formula (I), in which R1 and R2 independently denote a straight or branched alkyl with 1-8 carbon atoms, are mixed with one or more protonic acids selected from inorganic acids and organic carboxylic acids, used in amount of 0.01-100000 ppm with respect to dialkyl esters of dicarbonic acid or mixture thereof, and the obtained mixture is distilled.EFFECT: use of acid to stabilise diesters of dicarbonic acid against chemical and thermal decomposition.14 cl, 4 tbl, 2 exИзобретение относится к применению, по меньшей мере, одной протонной кислоты, выбранной из ряда неорганических кислот и органических карбоновых кислот, для стабилизации диэфиров диугольной кислоты против реакций химической и термической деструкции, причем протонные кислоты применяют в количестве от 0,01 до 100000 частей на млн в пересче
