Sebacic acid, identified by the CAS number 111-20-6 and also known as 1,10-decanedioic acid, is a saturated linear dicarboxylic acid with a ten-carbon chain. This molecule, a white crystalline powder, is derived from the processing of castor oil, specifically through the alkaline cleavage of ricinoleic acid. Its chemical structure, HOOC-(CH2)8-COOH, is the key to its remarkable versatility and widespread industrial significance.

The presence of two terminal carboxyl groups makes sebacic acid a highly reactive compound, readily undergoing reactions characteristic of carboxylic acids. Esterification, for instance, is a crucial reaction where sebacic acid reacts with alcohols to form sebacate esters. These esters are vital as plasticizers, improving the flexibility and processing of polymers like PVC, and as synthetic lubricants due to their excellent thermal stability and low-temperature properties.

Another significant reaction is polycondensation, where sebacic acid reacts with diamines or diols to form polymers. Its reaction with hexamethylenediamine yields Nylon 610, a high-performance polyamide prized for its mechanical strength, low moisture absorption, and good chemical resistance. This makes sebacic acid a critical intermediate in the production of advanced engineering plastics and fibers.

Sebacic acid's melting point, typically between 133-137°C, and boiling point of 294.5°C at 100 mmHg, indicate its stability at elevated temperatures, a property that translates directly into the performance of materials derived from it. Furthermore, its natural origin from castor oil positions it as a sustainable and renewable chemical feedstock, aligning with the growing demand for eco-friendly industrial solutions.

Beyond its polymeric applications, sebacic acid functions as an anti-corrosion agent. Its ability to form protective films on metal surfaces makes it a valuable additive in metalworking fluids and automotive coolants. In cosmetics, it acts as an emollient and pH regulator, contributing to skin hydration and product stability.

The fundamental chemistry of sebacic acid—its linear structure, dual reactivity, thermal stability, and renewable sourcing—underscores its importance as a chemical intermediate. Understanding these properties is key to appreciating its pervasive influence across industries, from high-performance polymers and lubricants to everyday personal care products.