Cinnamic acid is an organic compound with a pleasant aroma. It is found in cinnamon and has various applications in the fragrance, flavor, and pharmaceutical industries.
| IUPAC Name | (2E)-3-phenylprop-2-enoic acid |
| Molecular Formula | C9H8O2 |
| CAS Number | 621-82-9 |
| Synonyms | (E)-3-Phenylprop-2-enoic acid, trans-Cinnamic acid, 3-Phenylacrylic acid |
| InChI | InChI=1S/C9H8O2/c10-9(11)7-6-8-4-2-1-3-5-8/h1-7H,(H,10,11) |
Cinnamic Acid Properties
Cinnamic Acid Formula
The formula of 3-phenylacrylic acid is C9H8O2. It consists of nine carbon atoms, eight hydrogen atoms, and two oxygen atoms. The molecular formula represents the types and numbers of atoms present in a molecule.
Cinnamic Acid Molar Mass
The molar mass of 3-phenylacrylic acid is calculated by adding up the atomic masses of its constituent elements. With a formula of C9H8O2, its molar mass is approximately 148.16 grams per mole. Molar mass is essential in determining the amount of a substance in a given quantity.
Cinnamic Acid Boiling Point
3-Phenylacrylic acid has a boiling point of around 300 to 310 degrees Celsius. Boiling point is the temperature at which a substance changes from a liquid to a gas phase. The boiling point of 3-phenylacrylic acid influences its applications and behavior during various processes.
Cinnamic Acid Melting Point
The melting point of 3-phenylacrylic acid ranges from 133 to 136 degrees Celsius. Melting point is the temperature at which a substance changes from a solid to a liquid state. The melting point of 3-phenylacrylic acid is useful for its identification and characterization.
Cinnamic Acid Density g/mL
3-Phenylacrylic acid has a density of approximately 1.247 grams per milliliter. Density represents the mass of a substance per unit volume. The density of 3-phenylacrylic acid helps determine its behavior in different solvents and its suitability for specific applications.
Cinnamic Acid Molecular Weight
The molecular weight of 3-phenylacrylic acid is around 148.16 grams per mole. Molecular weight is the sum of the atomic weights of all the atoms in a molecule. It is important for various calculations and conversions in chemistry.
Cinnamic Acid Structure
3-Phenylacrylic acid has a structure characterized by a phenyl group attached to an acrylic acid moiety. It exists as a trans-isomer and is represented by the chemical formula (2E)-3-phenylprop-2-enoic acid. The structure of 3-phenylacrylic acid influences its reactivity and properties.
Cinnamic Acid Solubility
3-Phenylacrylic acid is sparingly soluble in water but dissolves readily in organic solvents such as ethanol and acetone. Solubility refers to the ability of a substance to dissolve in a solvent. The solubility of 3-phenylacrylic acid affects its applications and formulation in different industries.
| Appearance | White crystalline powder |
| Specific Gravity | 1.247 g/mL |
| Color | Colorless to pale yellow |
| Odor | Sweet, honey-like |
| Molar Mass | 148.16 g/mol |
| Density | 1.247 g/mL |
| Melting Point | 133-136 °C |
| Boiling Point | 300-310 °C |
| Flash Point | 161 °C |
| Water Solubility | Slightly soluble |
| Solubility | Soluble in organic solvents such as ethanol and acetone |
| Vapour Pressure | 0.0002 mmHg |
| Vapour Density | 5.08 (air = 1) |
| pKa | 4.44 |
| pH | 3.8-4.4 |
Cinnamic Acid Safety and Hazards
3-Phenylacrylic acid poses low safety hazards, but it is still important to handle it with caution. It may cause eye and skin irritation upon direct contact. Avoid inhaling dust or vapors, as they can irritate the respiratory system. In case of accidental ingestion, seek medical attention immediately. It is advisable to wear protective gloves and goggles when working with 3-phenylacrylic acid. Store it in a cool, dry place away from incompatible substances. While it is generally safe, always follow proper handling procedures, including good ventilation and personal protective equipment, to minimize potential risks and ensure a safe working environment.
| Hazard Symbols | None |
| Safety Description | – Avoid direct contact with eyes and skin\n- Use protective gloves and goggles\n- Ensure good ventilation\n- Store away from incompatible substances |
| UN IDs | Not applicable |
| HS Code | 29163900 |
| Hazard Class | Not classified as hazardous |
| Packing Group | Not applicable |
| Toxicity | Low toxicity |
Cinnamic Acid Synthesis Methods
There are various methods for synthesizing 3-phenylacrylic acid.
One common approach is the Perkin reaction, which involves the condensation of benzaldehyde with acetic anhydride in the presence of a base catalyst, such as sodium acetate. This reaction produces 3-phenylacrylic acid as the desired product.
Another method is the Knoevenagel condensation, where benzaldehyde reacts with malonic acid or its ester in the presence of a base, such as sodium ethoxide. This process leads to the formation of 3-phenylacrylic acid derivatives.
Oxidizing agents such as potassium permanganate or potassium dichromate in an acidic medium can oxidize cinnamaldehyde to obtain 3-phenylacrylic acid. This reaction converts the aldehyde group of cinnamaldehyde into a carboxylic acid group, resulting in the formation of 3-phenylacrylic acid.
Furthermore, enzymatic methods, using enzymes like phenylalanine ammonia-lyase, have been explored for the synthesis of 3-phenylacrylic acid from phenylalanine. These biocatalytic approaches offer greener and more sustainable alternatives.
Cinnamic Acid Uses
3-Phenylacrylic acid finds various applications in different industries due to its versatile properties. Here are some key uses of 3-phenylacrylic acid:
- Flavor and Fragrance Industry: The flavor and fragrance industry uses 3-phenylacrylic acid as a flavoring agent and fragrance enhancer in the production of food, beverages, and cosmetics, imparting a sweet, aromatic, and pleasant scent to these products.
- Pharmaceutical Industry: The pharmaceutical industry utilizes 3-phenylacrylic acid as an important intermediate in synthesizing pharmaceutical compounds. It serves as a starting material for producing drugs such as antihistamines, anti-inflammatory agents, and antifungal medications.
- UV Absorbers: Sunscreen lotions and cosmetic products employ 3-phenylacrylic acid derivatives, such as ethyl cinnamate and methyl cinnamate, as UV absorbers to protect the skin from harmful ultraviolet radiation.
- Antimicrobial Properties: 3-Phenylacrylic acid exhibits antimicrobial activity against specific bacteria and fungi, making it a valuable ingredient in antimicrobial agents and preservatives for food and cosmetic products.
- Agricultural Applications: 3-Phenylacrylic acid and its derivatives are under investigation for their potential use as plant growth regulators and natural pesticides. They can stimulate plant growth and function as defense compounds against pests and pathogens.
- Research and Chemical Synthesis: 3-Phenylacrylic acid serves as a reagent in various chemical reactions and as a starting material for synthesizing other compounds in research and industrial laboratories.
- Photostabilizers: The production of polymers, coatings, and plastics incorporates 3-phenylacrylic acid derivatives as photostabilizers to protect these materials from degradation caused by sunlight exposure.
- Food Preservatives: 3-Phenylacrylic acid derivatives, such as sodium cinnamate and calcium cinnamate, act as food preservatives, extending the shelf life of products and inhibiting the growth of microorganisms.
Questions:
Q: How many possible stereoisomers are possible for the bromination of trans-cinnamic acid?
A: Two possible stereoisomers are formed during the bromination of trans-cinnamic acid.
Q: What is the purpose of CH2Cl2 in the bromination of cinnamic acid?
A: CH2Cl2 (dichloromethane) is used as a solvent in the bromination of 3-phenylacrylic acid to dissolve the reactants and facilitate the reaction.
Q: Is cinnamic acid a mixed inhibitor?
A: No, 3-phenylacrylic acid is not classified as a mixed inhibitor.
Q: What is cinnamic acid?
A: 3-Phenylacrylic acid is an organic compound with a chemical formula of C9H8O2. It is a white crystalline solid with a characteristic aromatic odor.
Q: What is cinnamic acid used for?
A: 3-Phenylacrylic acid is used in various industries, including flavor and fragrance, pharmaceuticals, UV absorbers, agriculture, and as a research reagent.
Q: Is cinnamic acid soluble in water?
A: 3-Phenylacrylic acid is sparingly soluble in water.
Q: What is cinnamic acid not soluble in?
A: 3-Phenylacrylic acid is not soluble in non-polar solvents like hexane.
Q: How can cinnamic acid be removed?
A: 3-Phenylacrylic acid can be removed through techniques such as solvent extraction, recrystallization, or chromatography.
Q: What ratio of alcohol to acid is used to form ethyl cinnamate?
A: The ratio of alcohol to acid for the formation of ethyl cinnamate is 1:1.
Q: How many grams are in a mole of cinnamic acid?
A: The molar mass of 3-phenylacrylic acid is approximately 148.16 grams per mole.
Q: How can cinnamic acid be synthesized from benzaldehyde?
A: 3-Phenylacrylic acid can be synthesized from benzaldehyde through the Perkin reaction or the Knoevenagel condensation.
Q: What is the conversion of benzaldehyde to cinnamic acid known as?
A: The conversion of benzaldehyde to 3-phenylacrylic acid is known as an aldol condensation reaction.
Q: What is the product called when pyridinium tribromide reacts with trans-cinnamic acid?
A: The product formed from the reaction of pyridinium tribromide with trans-3-phenylacrylic acid is brominated 3-phenylacrylic acid.
Q: How can cinnamic acid be removed?
A: 3-Phenylacrylic acid can be removed through techniques such as solvent extraction, recrystallization, or chromatography.