Sulfur dioxide additions

A. Disodium Nitrosodisulfonate. In a 1-1. resin kettle, equipped with a mechanical stirrer, a thermometer, a gas-inlet tube suspended about 0.5 cm. above the bottom of the vessel, and an ice-cooling bath, are placed 15.0 g. (0.217 mole) of sodium nitrite (Note 1), 16.8 g. (0.200 mole) of sodium bicarbonate (Note 1), and 400 g. of ice. Sulfur dioxide (25.6 g. or 0.40 mole, Note 2) is passed into the cold, initially hetero-gcmcous mixture with stirring over a period of 40 minutes. Near the end of the sulfur dioxide addition, the light brown color of the reaction mixture fades almost completely. The resulting colorless to pale yellow solution of disodium hydroxyl-aminedisulfonato (Note 3), which has an approximate pH of 4,... 

Furthermore, the amphoteric behavior of the aluminum ion can be shown in sulfur dioxide as readily as in water. Just as AI(OH), is insoluble in water but dissolves readily in either a strong acid or basic solution, AMS03)3 is insoluble in liquid sulfur dioxide. Addition of either base (SO2-) or acid (SO2 ) causes the aluminum sulfite to dissolve, and it may be reprecipitated upon neutralization. 

Process reliability Sulfur dioxide addition for dechlorination purposes is reasonably reliable from a mechanical standpoint. The greatest problems are experienced with analytical control which may lower the process reliability. 

Cycloaddition reactions of sulfur dioxide. Addition of cyclooctatetraene to SbFs (1 eq.) in liquid SO2 at -70° leads to formation of (1) and (2) the former sulfone is rapidly isomerized to (2), which has been isolated. Formation of (1) represents an unusual 1,5-cycloaddition. The trivial name for (1) is... 

Four hundred milliliters of petroleum ether (dried-over sodium) is poured into a dry three-necked flask fitted with an inlet tube, a mechanical stirrer, and a barium oxide drying tube. The flask is cooled by an ice-salt mixture. Then 46 g. of gaseous amine is slowly added. Next 50 g. of dry sulfur dioxide is added, with continuous stirring and at such a rate that the temperature of the reaction mixture remains at about 0°. The solid sulfur dioxide addition compound is filtered quickly in a Buchner funnel. The product is then left in vacuo over phosphorus (V) oxide for several hours. Yield 90 to 96 g. (94 to 100 per cent). Anal. Calcd. for (CH3)3 N SO2 N, 11.4. Found N, 11.4 11.5. 

The oxidant is apart of liquid electrolyte in the cells of the lithium-thionyl chloride and lithium-sulfuryl chloride systems. In the first case, such oxidant electrolyte is the lithium tetrachloroaluminate (LiAlC ) solution in pure thionyl chloride or in thionyl chloride with a sulfur dioxide additive in the second case, it is the solution of the same salt in sulfuryl chloride. 

The sequence of functionalising the side-chain corresponds to the already described reaction pathway. Renewed sulfur dioxide addition is followed by... 

Lysozyme s application is directed primarily toward white wines for the control of LAB. Unlike compounds previously discussed, lysozyme exhibits activity toward all species and strains of LAB studied. At its suggested use level of 250-500 mg/L, the enzyme preparation may be added before alcoholic fermentation to prevent MLF, at some time during MLF, or upon completion to prevent subsequent activity of unwanted LAB. Its activity is not affected by ethanol, although upon reaction with tannin and pigment complexes, activity decreases (Villa, 1996). Similarly, bentonite dramatically decreases activity. In white juice, this ranged from 37% reduction after bentonite additions of 0.25 g/L to complete inactivation with additions of 1 g/L. In white wines, the impact of bentonite was less, ranging from 10% reduction with 0.25 g/L to 75% reduction at 1.0 g/L. The effect of sulfur dioxide additions in white wine was also investigated. In this case. Villa reports that SO2 at 80 mg/L had an indirect effect on lysozyme activity... 

Most winemakers prefer limiting air contact with crushed grapes and white juice as much as possible. An adapted sulfur dioxide addition to juice blocks the enzymatic oxidation of phenolic compounds. This philosophy is based on empirical observation juices of many grape varieties must conserve a green color dming the pre-fermentation phase to be transformed into fruity white wines. Oxidation phenomena must consequently be avoided as much as possible. 

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