D-Glucurolactone

Molecular formula: C6H8O6

Molecular weight: 176.13

This product is D-glucuronic acid-γ-lactone. Calculated by dry product, containing C6H8O6 should be 98.5 ~ 102.0%

【Properties】    This product is white crystal or crystalline powder; odorless, slightly bitter in taste; when exposed to light, the color gradually becomes darker; after dissolving in water, a part of the lactone becomes glucuronic acid, reaching a balanced state and showing an acidic reaction.

This product is easily soluble in water, slightly soluble in methanol and slightly soluble in ethanol.

【Melting point】    The melting point of this product (Appendix VI C) is 170~176℃, and it decomposes at the same time when melting.

【Specific rotation】    Take this product, accurately weigh it, add water to dissolve and quantitatively dilute it into a solution containing about 0.1g per 1ml, and measure it according to the law (Appendix VI E). The specific rotation is +18.0° to +20.0 at 25°C.

【Identification】    Take about 0.5g of this product, add 5ml of water to dissolve it, and test it according to the following method.

(1)    Take 1ml of solution, add 3,5-dihydroxytoluene solution (take 0.1g of 3,5-dihydroxytoluene and 5 drops of 10% ferric chloride solution, add hydrochloric acid to 100ml, shake up, and get final product) 4ml, heat in a water bath for a few minutes, the solution should be dark green, add 1ml of n-amyl alcohol after cooling, shake, and the green color is transferred to the n-amyl alcohol layer.

(2)    Take 1ml of the solution, add 4 drops of 15% ethanol solution of a-tea phenol, shake well, slowly add it along the tube wall into the test tube filled with concentrated sulfuric acid to form two liquid layers, the interface is green, and the upper layer is green. The water layer showed a violet color, and the color became darker after being placed.

【Check】    The clarity and color of the solution    Take 1.0g of this product, add 10ml of water to dissolve, the solution should be clear and colorless.

【loss on drying】    Get this product, dry to constant weight at 80 ℃, lose weight not more than 0.5%. (Appendix VIII L)

【Residue on ignition】    shall not more than 0.1%. (Appendix VIII N)

heavy metal    Take 1.0g of this product and inspect it according to the law (Appendix VIII H, the first method). The heavy metal content should not more than 10ppm.

【Determination of content】    Get about 0.5g of this product, accurately weigh it, add 50ml of freshly boiled and cooled water below 20°C to dissolve, below 20°C, accurately add 50ml of sodium hydroxide titration solution (0.1mol/L), Mix well, add 3 drops of phenolphthalein indicator solution, and immediately titrate with hydrochloric acid titration solution (0.1mol/L) until the red color completely disappears, and correct the titration result with a blank test. Every 1ml of sodium hydroxide titration solution (0. 1mol/L) is equivalent to 17. 61mg of C6H8O6.