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Cinnamic Acid Formula

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Carbon is a nonmetallic, tetravalent element that is of great use to humans. Its name is derived from Latin carbo which means charcoal or ember. Even though carbon is only 0.025% of the earth’s crust and 0.03% in the atmosphere it is of great importance to mankind. Carbon’s abundance in the earth’s core and the atmosphere is high.  The ability of carbon to form polymer at normal temperature is the reason it is commonly found in all living forms. The largest source of inorganic carbon is limestones, dolomite, etc.

What is Cinnamic Acid?

Cinnamic acids come under the category of organic compounds. This means it consists of carbon. The molecular formula of cinnamic acid is C9H8O2. It is a white crystalline solid. It is slightly soluble in water, The IUPAC name of cinnamic acid is (E)-3-phenyl prop-2-enoic acid. The molar mass of the following compound is 148 amu. It can be classified as an unsaturated carboxylic acid. It is naturally available in both cis and trans forms though trans isomer is more commonly found in nature. It is present in a number of plants. It is found in fruits and honey.

Preparation of Cinnamic acid

It was first synthesized by the base-catalyzed condensation of acetyl chloride and benzaldehyde and the hydrolysis of the acid chloride product. It can be prepared by the Knoevenagel condensation reaction. This includes the reaction between benzaldehyde and malonic acid in the presence of a weak base followed by acid-catalyzed decarboxylation.

It can be prepared by the oxidation of cinnamaldehyde

oxidation of cinnamaldehyde

 

It can be prepared by the condensation of benzyl chloride and acetic anhydride.

 Condensation of Benzyl Chloride and Acetic Anhydride

 

It can be prepared by Perkin’s reaction. This includes the reaction of Benzaldehyde and acetic anhydride in the presence of sodium acetate.

PERKINS REACTION

 

Structure of Cinnamic Acid

The molecular formula of cinnamic acid is C9H8O2. The IUPAC name of cinnamic acid is (E)-3-phenyl prop-2-enoic acid. The molar mass of the following compound is 148 amu. It can be classified as an unsaturated carboxylic acid.  It is naturally available in both cis and trans forms though trans isomer is more commonly found in nature.

Cinnamic Acid

 

Physical Properties of Cinnamic acid

  • It is a white crystalline solid.
  • It has a honey-like order.
  • The molar mass of cinnamic acid is 148 amu.
  • It is slightly soluble in water.
  • It is highly soluble in all organic solvents.
  • The cinnamic acid is acidic in nature and the pH is 3.21 
  • The density of cinnamic acid is 148 g/mol.

Chemical Properties of Cinnamic acid

  • It is aromatic in nature due to the presence of a benzene ring.
  • The melting point of cinnamic acid is 113°C
  • The boiling point of cinnamic acid is 300°C
  • The molar mass of cinnamic acid is 148 amu.
  • It is optically active in nature.
  • Trans-Cinnamic acid reacts with excess bromine to form 2,3-dibromo-3-phenylpropanoid acid.

     

Bromination of Cinnamic Acid

 

Uses of Cinnamic acid

  • Cinnamic acid is used as flavoring.
  • It is widely used in the manufacturing of synthetic Indigo.
  • It is used in some pharmaceuticals. 
  • One of the major use of mic acid is its use in the production of methyl cinnamate, ethyl cinnamate, and benzyl cinnamate which are mainly used in the perfume industry.
  • Cinnamic acid is used in the production of sweetener aspartame. 
  • Cinnamic acid is used in a lot of sunscreens due to its UV protection properties.

Health Hazards of Cinnamic Acid

  • It is safe when the dosage of cinnamic acid is less but large quantities of cinnamic acid are considered harmful to the body.
  • If the concentration of cinnamic acid in cosmetics is high it may trigger allergic reactions.
  • If the cinnamic acid converts to cinnamaldehyde it is highly toxic to the body.
  • It may lead to irritation in the eyes on contact.
  • If inhaled it may even cause respiratory irritation and a problem with breathing.

FAQs on Cinnamic acid

Question 1: Write a short note on Cinnamic acid.

Answer: 

Cinnamic acids come under the category of organic compounds. This means it consists of carbon. The molecular formula of cinnamic acid is C9H8O2. It is a white crystalline solid. It is slightly soluble in water, the IUPAC name of cinnamic acid is (E)-3-phenyl prop-2-enoic acid. The molar mass of the following compound is 148 amu. It can be classified as an unsaturated carboxylic acid. It is naturally available in both cis and trans forms though trans isomer is more commonly found in nature. It is present in a number of plants.

Question 2: Explain the structure of Cinnamic acid.

Answer:

The molecular formula of cinnamic acid is C9H8O2. The IUPAC name of cinnamic acid is (E)-3-phenyl prop-2-enoic acid. The molar mass of the following compound is 148 amu. It can be classified as an unsaturated carboxylic acid.  It is naturally available in both cis and trans forms though trans isomer is more commonly found in nature.

Question 3: Explain some preparation methods for Cinnamic acid.

Answer:

It was first synthesized by the base-catalyzed condensation of acetyl chloride and benzaldehyde and the hydrolysis of the acid chloride product. It can be prepared by the Knoevenagel condensation reaction. This includes the reaction between benzaldehyde and malonic acid in the presence of a weak base followed by acid-catalyzed decarboxylation. It can be prepared by the oxidation of cinnamaldehyde It can be prepared by the condensation of benzyl chloride and sodium acetate. It can be prepared by Perkin’s Reaction. This includes the reaction of Benzaldehyde and acetic anhydride in the presence of sodium acetate.

Question 4: Write a short note on the uses of cinnamic acid.

Answer: 

Cinnamic acid is used as flavoring. It is widely used in the manufacturing of synthetic Indigo. It is used in some pharmaceuticals. One of the major use of mic acid is its use in the production of methyl cinnamate, ethyl cinnamate, and benzyl cinnamate which are mainly used in the perfume industry. Cinnamic acid is used in the production of sweetener aspartame. 

Question 5: What is the nature of Cinnamic acid?

Answer:

Cinnamic acid is acidic in nature and the pH of cinnamic acid is 3.21. It is an organic acid so it is considered a weak acid. When it is mixed with a weak base then salt and water are produced.

Question 6: List some properties of Cinnamic acid.

Answer:

It is a white crystalline solid. It has a honey-like order. It is aromatic in nature due to the presence of a benzene ring. The melting point of cinnamic acid is 113°C. The boiling point of cinnamic acid is 300°C. The molar mass of cinnamic acid is 148 amu. It is slightly soluble in water. It is highly soluble in all organic solvents. The cinnamic acid is acidic in nature and the pH is 3.21 

Question 7: Is Cinnamic Acid harmful to the body?

Answer: 

It is safe when the dosage of cinnamic acid is less but large quantities of Cinnamic acid is considered harmful to the body. If the concentration of cinnamic acid in cosmetics is high it may trigger allergic reactions. If the cinnamic acid converts to cinnamaldehyde it is highly toxic to the body. It may lead to irritation in the eyes on contact. If inhaled it may even cause respiratory irritation and a problem with breathing.



Last Updated : 19 Dec, 2023
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