Solubility: Soluble in water, aniline, azobenzene, ethyl acetate and the mixture of alcohol and water. Insoluble in gasoline, petroleum, anhydrous alcohol, CHCL3 and CCL4.
Solubility in water: 2. 1 g sucrose can be dissolved per gram of water, that is, the solubility is 2 10g(25℃). This is a sugar with high solubility.
Melting point: 186℃
Energy density: 17 kj/m3
Be careful not to have silver mirror reaction. Reason: Sucrose (which has no hemiacetal (ketone) structure) is irreversible.
Sweeteners: tea, coffee, potions, pills, etc.
Chemical properties of sucrose
Sucrose and sucrose solution will produce various chemical reactions under the action of heat, acid, alkali and yeast. The result of the reaction not only directly causes the loss of sucrose, but also produces some substances harmful to sugar production.
1. Pyrolysis
Crystallized sucrose is heated to 65438 060℃, melted into viscous transparent liquid, and recrystallized after cooling. When the heating time is prolonged, sucrose is decomposed into glucose and dehydrated fructose. At the higher temperature of 190-220℃, sucrose was dehydrated and concentrated into caramel. When caramel is further heated, products such as carbon dioxide, carbon monoxide, acetic acid and acetone will be produced. Under humid conditions, sucrose decomposes at 100℃, releasing water and turning black.
After the sucrose solution is heated and boiled for a long time under normal pressure, the dissolved sucrose will slowly decompose into the same amount of glucose and fructose, that is, it will be transformed. When sucrose solution is heated above 108℃, it will hydrolyze rapidly, and the greater the concentration of sugar solution, the more obvious the hydrolysis effect will be. The metal materials used in the boiling vessel also have an effect on the conversion rate of sucrose. For example, the transformation of sucrose solution in bronzes is much greater than that in silverware, and glass containers have little effect.
2. The role of acid
When the sucrose solution is acidic, the sucrose conversion is faster. Concentrated acid has a greater decomposition effect on sugar solution. For example, concentrated sulfuric acid can quickly dehydrate solid sucrose and coke it into black products. In pure sucrose solution, as long as there is a small amount of free acid, the conversion of sucrose can be carried out quickly. However, this is not the case with sucrose in pressed sugarcane juice. Because the neutral salt of weak acid in sugarcane juice will inhibit the conversion of sucrose.
3. The role of alkali
Dilute alkali solutions, such as calcium hydroxide, potassium hydroxide and sodium solution, will not decompose sucrose even if boiled. When concentrated alkali solution is heated in sugar solution, sucrose is decomposed into furfural, acetone, lactic acid, acetic acid, formic acid, carbon dioxide and other products. The decomposition degree and product type depend on the concentration and temperature of hydroxyl ions. Sucrose can be combined with moderate concentration of alkali to form basic sucrose salt.
4. The role of salt
When sucrose and salt exist in water at the same time, their solubility will change, and the degree of change depends on the concentration of both sides and the nature of salt.
5. Oxidation
The combustion or biological oxidation of sucrose produces carbon dioxide and water. Potassium permanganate can oxidize sucrose into carbon dioxide, formic acid, acetic acid and oxalic acid in neutral or acidic solution, but it can only be partially oxidized into oxalic acid and carbon dioxide under alkaline conditions.
6. Effects of microorganisms on sucrose
The dilute solution of sucrose is easily infected by microorganisms, but with the increase of sugar juice concentration, the probability of infection decreases. In addition, it is also related to the temperature and pH value of sugar juice. Generally speaking, the optimum temperature for microbial reproduction is between 30-45℃, but when heated to 80℃, most microorganisms can be inhibited or killed.
Use:
Soda, candy, biscuits, cakes, bacon, seasonings, commodities, daily necessities and futures.
The combination of sucrose and L- arabinose can not only enjoy the sweetness of eating sugar, but also cause obesity, hypertension and hyperglycemia.