Metabisulfite potassium

Disulfurous acid dipotassium pyrosulfite dipotassium salt E224 kali disulfis potassium pyrosulfite. 

Melting point 190°C although potassium metabisulfite decomposes at temperatures above 150°C. 

Solubility soluble 1 in 2.2 of water practically insoluble in ethanol (95%). 

Potassium metabisulfite should be stored in a cool, dark place. When stored at a maximum temperature of 25°C and maximum relative humidity of 45%, the shelf-life is 6 months. Potassium metabisulfite decomposes at temperatures above 150°C. In the air, it oxidizes to the sulfate, more readily in the presence of moisture. 

In aqueous solution, potassium metabisulfite forms potassium bisulfite (KHSO3) which exerts a strong reducing effect. 

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Dipping solution Dissolve 3 g 1-naphthol in 150 ml methanol and add 1350 ml water. Dissolve 0.5 g potassium disulfite (potassium metabisulfite) in this solution, add 20 ml glacial acetic acid and dissolve 0.5 g iron(II) sulfate THiO followed by 2.2 g N -ethyl-N -(2-methanesulfonamidoethyl)-2-methyl-l,4-phenylenediamine (sesquisulfate, monohydrate) (color developer 3, Merck). Care should be taken at each step that the solution has clarified before adding further components. 

BHT, potassium metabisulfite, PMSF and DTT are added just before homogenization, as these reagents readily inactivate. 

Sulfites, a group of six compounds that have been on the GRAS list since 1959, include sulfur dioxide (S02), sodium sulfite (Na2S03), sodium metabisulfite (NaS205), potassium metabisulfite (KS205), sodium bisulfite (NaHS03), and... 

Anonymous. Final report on the safety assessment of sodium sulfite, potassium sulfite, ammonium sulfite, sodium bisulfite, ammonium bisulfite, sodium metabisulfite and potassium metabisulfite. Int J Toxicol 2003 22(suppl 2) 63. 

The sodium and potassium salts of S02 are simpler and more pleasant to use as they do not have the odor of the pure liquid or the 5% water solution. They are rapidly soluble in must where they react with a small portion of the natural acid present to liberate S02. There are two sodium salts of S02 available, Na2S03 (neutral sodium sulfite) and NaHS03 (sodium acid sulfite). The latter compound introduces less sodium into the wine and removes less acid from the wine for an equivalent amount of S02 liberated. Potassium acid sulfite and potassium pyrosulfite (potassium metabisulfite) are the two salts of potassium with S02 that are readily available, soluble in grape juice, and capable of yielding S02 upon reaction with the acid of the juice. Potassium salt is recommended when it is desired to keep the wine low in sodium ion content for diet reasons. The salts should be edible or food product grade, that is, free of heavy metals and other toxic impurities. They must be stored in tightly closed containers or they will react with the water vapor and... 

To prepare the necessary potassium sulfite Dissolve 44g of potassium metabisulfite m a solution of lOOg of potassium hydroxide in one liter of water, add 5 drops of phenol-phthalem indicator and then more of the 10% potash solution until a pink color just forms. Add the latter solution drop by drop from a separatory funnel KHSO f KOH ------- KaSOs + H 0]... 

Dissolve 1 g of potassium metabisulfite (K2S205) in 5 ml of distilled water. 

The second approach to the preparation of 1-telluracyclohexane involves the reaction of 1,5-diiodopentane with elemental tellurium under heating (45JCS11). Initially formed (in 63% yield) 1,1-diiodo-l-telluracyclohexane 6 (X = I) is readily reduced to 1 by potassium metabisulfite in almost quantitative yield. 

Photosensitization. Bon (Bll) proposed the following method. Press the wet strip against silver bromide paper, expose for a short period to light, develop with a hard developing bath, and fix immediately with concentrated potassium metabisulfite. Protein at 1 (xg/mm3 gave a distinct spot on the photographic paper. 

Potassium metabisulfite will sometimes be encountered in formulas. For photographic purposes, there is no practical difference between potassium and sodium metabisulfite except that the potassium salt is more expensive. They can be exchanged weight for weight in most formulas. 

Other chemicals that can be used to make stop baths are boric acid, citric acid, and sodium bisulfite. Chemicals that should not be used are chrome alum and potassium salts, such as potassium metabisulfite or potassium sulfite, either of which can cause green stains on some enlarging papers. In addition, the introduction of potassium salts into a fixing bath can convert the bath to potassium thiosulfate, which is nearly inactive as a fixing agent.1... 

Cautiom Powerful oxidizing agent its stain can be removed with a solution of potassium metabisulfite or sodium bisulfite. 

Water at 125F/52C, 750.0ml Metol, 0.8 g Sodium sulfite, 45.Og Hydroquinone, 1.2 g Sodium carbonate, monohydrate, 8.0g Potassium metabisulfite, 4.0g Potassium bromide, 1.5 g Water to make 1.0 liter... 

Although it is usually acceptable to substitute sodium metabisulfite for potassium metabisulfite, it is not recommended in this formula. 

The formula as originally published calls for 10.0 grams of potassium metabisulfite, crystalline. Develop film for 12 to 13 minutes at 68F/20C. 

Water at room temperature, 300.0ml Potassium metabisulfite, 1.5 g Sodium sulfite, 30.0g... 

The sparkling wine in the receiving tank is cloudy, contains no sugar, and requires clarification, sweetening, and treatment before final bottling. After analysis, the S02 level of the wine is adjusted by adding potassium metabisulfite. Erythorbic acid is added also. These are for antimicrobial and antioxidation purposes. 

Identification Transfer 1 g of sample and 1 g of potassium metabisulfite to a 100-mL volumetric flask, dissolve in about 50 mL of pH 3.0 Citrate-Citric Acid Buffer (see Assay, below), and dilute to volume with the same buffer. The red color caused by anthocyanins is bleached. 

Potassium Metabisulfite occurs as white or colorless, free-flowing crystals, crystalline powder, or granules. It gradually... 

The most widely used of these sulfites is potassium metabisulfite. In practice, a value of 50 percent of active S02 is used. When sulfur dioxide is dissolved in water, the following ions are formed ... 

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