Adipic acid is a chemical compound used in the production of nylon and other polymers. It is also used as a food additive and has a tart taste.
| IUPAC Name | Hexanedioic acid |
| Molecular Formula | C6H10O4 |
| CAS Number | 124-04-9 |
| Synonyms | Adipinic acid, Hexane-1,6-dioic acid, 1,4-Butanedicarboxylic acid |
| InChI | InChI=1S/C6H10O4/c7-5(8)3-1-2-4-6(9)10/h1-4H2 |
Adipic Acid Properties
Adipic Acid Formula
The formula of adipic acid is C6H10O4. It consists of six carbon atoms, ten hydrogen atoms, and four oxygen atoms. This chemical formula represents the arrangement and composition of atoms in a molecule of adipic acid.
Adipic Acid Molar Mass
The molar mass of adipinic acid is approximately 146.14 grams per mole. Molar mass is the mass of one mole of a substance, and in the case of adipinic acid, it is determined by adding the atomic masses of its constituent elements.
Adipic Acid Boiling Point
Adipinic acid has a boiling point of around 337 degrees Celsius. The boiling point is the temperature at which a substance changes its phase from a liquid to a gas. Adipinic acid reaches this temperature when sufficient energy is supplied.
Adipic Acid Melting Point
The melting point of adipinic acid is approximately 152 degrees Celsius. This is the temperature at which solid adipinic acid changes into a liquid state. As heat is applied, the intermolecular forces holding the solid together are overcome, resulting in melting.
Adipic Acid Density g/mL
Adipinic acid has a density of about 1.36 grams per milliliter. Density is a measure of how tightly packed the molecules are within a substance. In the case of adipinic acid, it indicates the mass of the acid per unit volume.
Adipic Acid Molecular Weight
The molecular weight of adipinic acid is 146.14 grams per mole. It is calculated by summing up the atomic weights of all the atoms present in the molecular formula of adipinic acid. Molecular weight provides information about the mass of a molecule.
Adipic Acid Structure
The structure of adipinic acid consists of a chain of six carbon atoms with two carboxyl (-COOH) functional groups attached to the ends. It has a linear arrangement and is known as a dicarboxylic acid due to the presence of two carboxyl groups.
Adipic Acid Solubility
Adipinic acid is moderately soluble in water. It forms hydrogen bonds with water molecules, allowing it to dissolve to some extent. The solubility of adipinic acid is influenced by factors such as temperature, pH, and the presence of other substances in the solution.
| Appearance | White crystalline powder |
| Specific Gravity | 1.36 g/mL |
| Color | Colorless |
| Odor | Odorless |
| Molar Mass | 146.14 g/mol |
| Density | 1.36 g/mL |
| Melting Point | 152 °C |
| Boiling Point | 337 °C |
| Flash Point | 196 °C |
| Water Solubility | 1.95 g/100 mL at 25 °C |
| Solubility | Soluble in solvents such as alcohol and ether |
| Vapor Pressure | 0.002 mmHg at 25 °C |
| Vapor Density | 5.1 (Air = 1) |
| pKa | pKa1: 4.41, pKa2: 5.41 |
| pH | 2.5 – 3.5 |
Adipic Acid Safety and Hazards
Adipinic acid poses minimal hazards to human health and the environment when handled and used properly. However, like any chemical, it is important to follow safety precautions. Direct contact with adipinic acid may cause mild irritation to the skin and eyes. Ingestion or inhalation in large amounts can lead to gastrointestinal disturbances or respiratory irritation. It is advisable to use protective equipment such as gloves and goggles when working with adipinic acid. In case of accidental exposure, promptly wash affected areas with water and seek medical attention if necessary. Proper storage and disposal practices should be followed to prevent environmental contamination.
| Hazard Symbols | None |
| Safety Description | – Avoid direct contact with skin and eyes. – Use protective equipment (gloves, goggles) when handling. – Store in a cool, dry place away from incompatible substances. – Follow proper handling and disposal procedures. |
| UN IDs | Not Applicable |
| HS Code | 291712 |
| Hazard Class | Not Classified |
| Packing Group | Not Applicable |
| Toxicity | Low toxicity when used and handled correctly. |
Adipic Acid Synthesis Methods
Adipinic acid can be synthesized through different methods. One common method for synthesizing adipinic acid involves reacting cyclohexanone with nitric acid in the presence of a catalyst, such as vanadium pentoxide. This reaction oxidizes cyclohexanone and converts it into adipinic acid.
Another method utilized on an industrial scale is the oxidation of cyclohexanol using air or oxygen. First, cyclohexanol undergoes dehydrogenation to form cyclohexanone. Then, cyclohexanone is further oxidized to produce adipinic acid.
An alternative approach is the carbonylation of 1,3-butadiene. In this process, 1,3-butadiene undergoes a carbonylation reaction using carbon monoxide and water in the presence of a catalyst, such as a palladium complex. The reaction yields adipinic acid.
Furthermore, bio-based routes have been explored for adipinic acid synthesis. This includes the fermentation of glucose or other sugars by microorganisms, which convert the sugars into adipinic acid. These bio-based methods offer potential for a more sustainable and environmentally friendly production process.
The choice of synthesis method depends on factors such as cost, efficiency, and environmental considerations.
Adipic Acid Uses
Adipinic acid finds various applications across different industries due to its versatile properties. Here are some common uses:
- Adipinic acid plays a crucial role in the production of nylon 6,6, a widely used synthetic fiber, by reacting with hexamethylenediamine to form nylon polymers. These polymers find applications in textiles, carpets, and engineering plastics.
- The polymer and resin industry utilizes adipinic acid as a building block for synthesizing polyurethane, polyesters, and polyamides, which have diverse applications in coatings, adhesives, and automotive components.
- Adipinic acid serves as a food additive in certain beverages and food products to provide a sour taste. It acts as an acidulant and flavor enhancer in gelatin desserts, fruit-flavored beverages, and carbonated drinks.
- The pharmaceutical industry employs adipinic acid in the production of various medications. It acts as an excipient in tablets and capsules, contributing to the controlled release and stability of active pharmaceutical ingredients.
- Adipinic acid acts as an intermediate in the synthesis of various dyes and pigments used in textiles, paints, and inks, enabling the production of vibrant colorants.
- Adipinic acid finds application in the manufacturing of esters used as lubricant additives. These esters improve the viscosity and lubricity of oils, thereby enhancing the performance and longevity of machinery.
- Adipinic acid derivatives function as plasticizers in the plastics industry, enhancing flexibility, durability, and resistance to temperature changes when incorporated into polymers.
Adipinic acid’s diverse range of applications makes it an important compound in industries such as textiles, plastics, food, pharmaceuticals, and chemicals.
Questions:
Q: What is adipic acid?
A: Adipinic acid is a chemical compound with the molecular formula C6H10O4. It is a white crystalline solid and belongs to the class of dicarboxylic acids.
Q: Which of the following will give a crosslinked polymer when condensed with adipic acid?
A: Hexamethylenediamine, when condensed with adipinic acid, will form a crosslinked polymer known as nylon 6,6.
Q: How many grams of oxygen would be needed to make 40.0 moles of adipic acid by this reaction?
A: For each mole of adipinic acid, three moles of oxygen are required. Therefore, 40.0 moles of adipic acid would require 120.0 moles (or 1920 grams) of oxygen.
Q: How many moles in 146.14 g/mol adipic acid?
A: There is 1 mole of adipinic acid in 146.14 g/mol.
Q: What product will be formed when adipic acid is heated?
A: When adipinic acid is heated, it undergoes thermal decomposition to produce water, carbon dioxide, and cyclopentanone.
Q: What product is formed when hexamethylenediamine reacts with adipic acid?
A: Hexamethylenediamine reacts with adipinic acid to form a polymer known as nylon 6,6.
Q: What is the empirical formula of adipic acid if it contains 49.32% C, 43.84% O, and 6.85% H by mass?
A: The empirical formula of adipinic acid is C3H6O4.
Q: Could you substitute adipoyl chloride with adipic acid in this reaction? Explain why or why not.
A: No, adipinic acid cannot be directly substituted for adipoyl chloride in certain reactions because adipoyl chloride provides a reactive acyl chloride group, which reacts differently than the carboxylic acid group in adipinic acid.
Q: Is adipic acid polar or nonpolar?
A: Adipinic acid is a polar compound due to the presence of carboxylic acid functional groups, which exhibit polarity.
Q: How is adipic acid used in food?
A: Adipinic acid is used as a food additive to provide a tart or sour taste in certain beverages and food products, such as carbonated drinks and gelatin desserts.
Q: During the synthesis of adipic acid from cyclohexanone, what is the spot test for?
A: During the synthesis of adipinic acid from cyclohexanone, a spot test can be performed to detect the presence of adipic acid. The test involves the reaction of the sample with a reagent such as bromine water, which would form a white precipitate of adipinic acid.