Physical and chemical properties of fructose

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Fructose, a monosaccharide, is an isomer of glucose with a chemical formula of C6H12O6. It exists in large quantities in fruit juice and honey in a free state. Fructose can also combine with glucose to form sucrose.

physical properties

Density: 1.694g/cm3

Boiling point: 551.7°C

Flash point: 301.5°C

Refractive index: 1.574

Appearance: Pure product is colorless crystal, aqueous solution is viscous liquid

chemical properties

Glucose and fructose are isomers of each other. Glucose is a polyhydroxy aldehyde (aldose), and fructose is a polyhydroxy ketone (ketose). There is no aldehyde group in the fructose molecule. It seems that silver cannot occur Mirror reaction, but in fact it is not, the main reason is that fructose can undergo two reactions in alkaline solution: one is to become aldose through enolization. The second is cracking to produce organic compounds containing aldehyde groups. Due to the influence of multiple hydroxyl groups on the ketone group in the fructose molecule, the fructose can also undergo a silver mirror reaction and be oxidized by the newly prepared Cu(OH)2. It can be seen that the fructose solution always contains aldose and aldehyde-containing organic matter, which can undergo a silver mirror reaction with the alkaline silver-ammonia solution. Therefore, both fructose and glucose are reducing sugars. The effect of silver mirror reaction with fructose is similar to that of glucose, the reaction conditions are slightly higher than glucose, 60-100 ℃, the mass fraction of fructose solute can be 1%, the mass fraction of silver nitrate solution and ammonia solute can be 2%-4%. Under these conditions, high-quality silver mirrors can be obtained.

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