The story of the invention of aniline violet, humanity’s first synthetic dye
Humans have discovered and applied natural minerals and plant dyes for at least 4,000 to 5,000 years, and have cultivated and used plant indigo. Dyes have been around for more than 2,000 years. Later, scientists analyzed the chemical structure of plant indigo and artificially synthesized chemical indigo. The first chemical dye synthesized in human history was aniline violet, which was more than 20 years earlier than chemical indigo. Of course, this invention was originally an accident. The scientists did not intend to make dyes, but to synthesize an anti-malarial drug.
In 1856, in the laboratory of Dean Hoffman, the famous organic chemist of the Royal College of Chemistry, 18-year-old graduate student W.H. Perkin was synthesizing cinchona (quinine), a specific anti-malarial drug. To work, at that time the drug had to be extracted from the bark of a cinchona tree where the South American Indians lived, so the price of the drug was very expensive in Europe. Since the theoretical and experimental foundations of medicinal chemistry were not yet complete at that time, people were still unable to know the exact molecular structure of cinchona. Perkin could only continue to explore through a large number of experiments. One day, he added the strong oxidizing agent potassium dichromate to the sulfate of aniline. As a result, a pitch-like black residue appeared in the flask. Perkin knew that he had failed again! He had to clean the flask in order to continue the experiment. Considering that this charred substance must be an organic substance that is probably difficult to dissolve in water, Perkin used alcohol to clean the flask. When the alcohol was added to the flask, Perkin suddenly opened his tired eyes: the black substance was dissolved by the alcohol into a beautiful and eye-catching purple! As an experienced graduate student in chemistry, he immediately recognized that this unexpected phenomenon would lead to an important invention. Considering that people's clothes at that time were dyed with natural plant dyes that were difficult to preserve and had poor color fastness. Neither the brightness of the colors nor the completeness of the color spectrum was satisfactory, Perkin thought of trying to dye it with this purple substance. Cloth, but unfortunately his experiment was not successful. The dyed cotton almost fell off as soon as it was washed with water! He was not discouraged, and experimented with wool and silk. He found that this substance, which could not be dyed on cotton, could be dyed on silk and wool very easily, and the color was brighter than various plant dyes at the time. It doesn't fade even when washed in soapy water. This is the world's first synthetic chemical dye, aniline violet. Although Perkin did not create quinine, he obtained a patent for the invention of synthetic aniline violet. The gorgeous colors of synthetic dyes attracted the favor of Queen Victoria at the time. The unexpected success greatly encouraged his entrepreneurial impulse. In 1857, Perkin established the world's first synthetic dye factory to produce aniline violet in Harrow. As a result, he became the world's richest man.