Glucose - C6H12O6

What is Glucose?

Glucose is a simple sugar with six carbon atoms and one aldehyde group. This monosaccharide has a chemical formula C₆H₁₂O₆.

It is also known as dextrose. It is referred to as aldohexose as it contains 6 carbon atoms and an aldehyde group. It exists in two forms, open-chain or ring structure. It is synthesized in the liver and kidneys of animals. In plants, it is found in fruits and in different parts of plants. D- glucose is the naturally occurring form of glucose. It can occur either in solid or liquid form. It is water-soluble and is also soluble in acetic acid. It is odourless and sweet to taste. In the year 1747, Andreas Marggraf, a German chemist, isolated glucose from raisins. In the year 1838, Jean Baptiste Dumas coined the word glucose.

Table of Content

• • Structure of Glucose
  • Properties of Glucose
  • Preparation of Glucose
  • Uses of Glucose
  • FAQs

Structure of Glucose – C₆H₁₂O₆

Properties of Glucose – C₆H₁₂O₆

Glucose can be called as aldohexose as well as dextrose. It is a monomer of many larger compounds such as carbohydrates, starch, and cellulose. On earth, this is the most abundant organic compound. On the basis of the following evidence, it was assigned the structure illustrated above:

1. It has a molecular formula of C₆H₁₂O₆
2. When HI is heated for a long time, n-hexane is formed which indicates that all the six carbon atoms are linked in a straight chain.
3. The oxime is formed when glucose reacts with hydroxylamine and cyanohydrins on the addition of hydrogen cyanide to it. This reaction can confirm the presence of the carbonyl group in glucose.
4. On the reaction of glucose with a mild oxidizing agent like bromine water, the glucose gets oxidized to a carboxylic acid that contains six carbon atoms. This indicates that the carbonyl group is present as an aldehyde group.
5. The presence of -OH group is confirmed after the acetylation of glucose with acetic acid, which gives glucose pentaacetate.
6. Glucose as well as gluconic acid both yields dicarboxylic acid and saccharic acid on oxidation with nitric acid. The presence of primary alcohol is indicated by this.

Preparation Of Glucose (C₆H₁₂O₆)

Sucrose (cane sugar) and starch are the two major sources of Glucose.

Preparation from sucrose or cane sugar:

  Sucrose is a disaccharide with the formula C₁₂H₂₂O₁₁. On boiling an aqueous solution of sucrose with dilute HCl or dilute H₂SO₄, Glucose and Fructose are formed in equimolar proportions.

                              C₁₂H₂₂O₁₁  +  H2O  →  C₆H₁₂O₆   +  C₆H₁₂O₆

                                  Sucrose                         Glucose         Fructose

Preparation from starch: 

It is a polysaccharide that when boiled with dilute H₂SO₄ at 393 K under 2 to 3 atmosphere pressure, gives glucose.

                                   ( C₆H₁₂O5)n   +   n H2O   →    nC₆H₁₂O₆  

                                          Starch                                   Glucose

Uses Of Glucose (C₆H₁₂O₆)

• It is used in the treatment of hypoglycemia (low blood sugar)
• It is given to patients who are very sick and cannot eat as it provides carbohydrate calories
• It is used in the treatment of increased potassium levels in the blood (hyperkalemia)
• It is used as a precursor for the synthesis of substances.

Also, Read:

Learn more about the isomerism, L-glucose, D- glucose and the structure of C₆H₁₂O₆ from the expert faculties at BYJU’S.