Difference between dihexanoic acid and adipic acid

As dicarboxylic acids, dihexanoic acid (chemical formula: HOOC-(CH2)4-COOH) and adipic acid (phthalic acid, chemical formula: HOOC-CH2-C(CH3)2-CH2-COOH) have significant differences in chemical properties and applications due to their structural differences. In this paper, the difference between dihexanoic acid and adipic acid will be analyzed in depth from the basic structure, physical properties, chemical reaction characteristics and industrial application.

1. basic structure difference

The structural difference between dihexanoic acid and adipic acid is mainly reflected in the carbon chain structure of the molecular chain. The molecular formula of two hexanoic acid is C6H10O4, and the molecular structure is two carboxyl groups connected by four carbon chains to form a straight chain structure. The molecular formula of adipic acid is C8H6O4, and the two carboxyl groups in its structure are connected by a branched carbon chain to form a ring-like structure.

This structural difference leads to significant differences in chemical and physical properties. Dihexanoic acid has a symmetrical structure, while adipic acid has a higher stability due to the branched structure.

analysis of physical properties of 2.

The physical properties of dihexanoic acid and adipic acid are mainly manifested in melting point, boiling point and solubility. The melting point of dihexanoic acid is high, about 161°C, and the boiling point is 241°C. It has good solubility and is soluble in water and ethanol. The melting point of adipic acid is slightly lower, about 149 ° C., and the boiling point is 235 ° C., which also has good solubility.

In terms of molecular structure, the symmetrical structure of dihexanoic acid makes it easier to maintain stability at high temperatures, while the branched structure of adipic acid makes it easier to decompose at high temperatures.

3. chemical reaction characteristics

Dihexanoic acid and adipic acid exhibit different properties in chemical reactions. As a dicarboxylic acid, dihexanoic acid has high acidity and a pKa of about 4.2, and is suitable for the preparation of neutral or weakly acidic polyesters. Adipic acid is more acidic, pKa is 2.9, because of its stronger acidity, commonly used in the preparation of acidic polyester.

The strong acidity of adipic acid makes the esters formed when it reacts with alcohols have better dehydration properties, so it is often used in industrial applications to produce plastics. Because of its weak acidity, dihexanoic acid is often used in the production of neutral plastics.

4. industrial application comparison

In industrial applications, dihexanoic acid and adipic acid have their own unique advantages. Dihexanoic acid is widely used in the production of polyester materials, such as denim, synthetic fibers, etc. Its production process usually uses ester exchange process, the process is more mature.

Adipic acid is mainly used in the production of polymer materials, such as polyester and plastic. Its strong acidity makes it more stable and lower energy consumption in plastic production.

5. environmental impact analysis

From the perspective of environmental protection, the production process of dihexanoic acid is relatively mild and has less impact on the environment, while the production process of adipic acid may produce more harmful substances due to its strong acidity, which has a greater impact on the environment.

6. conclusion

As dicarboxylic acids, dihexanoic acid and adipic acid have significant differences in structure, physical properties, chemical reaction characteristics and industrial applications. Dihexanoic acid is widely used in the production of polyester materials because of its symmetrical structure with good stability, while adipic acid is mainly used in the production of polymer materials because of its strong acidity. When choosing dihexanoic acid or adipic acid, the most suitable material should be selected according to specific industrial needs and environmental protection requirements.