Shulou(Shulou.com)11/24 Report--

This article comes from the official account of Wechat: back to Park (ID:fanpu2019), author: snow

A magical story about drugs, waste, scientists, businessmen, aristocrats, marine life and bird droppings reveals the mysteries of chemistry like a complex compound.

About organic synthesis, we tell an interesting story: man's first synthetic dye, purple (aniline purple mauveine), comes from an unexpected discovery.

Products of coal tar in 1856, William Perkin, an 18-year-old Englishman, tried to synthesize quinine from coal tar in his humble laboratory. Quinine was the only cure for malaria in those days, and the price was ridiculously high because it came from grinding the bark of cinchona trees in the tropics (so it was also called cinchona cream).

Perkin, pictured on the left, is 14 years old. Photo Source: sciencehistory.org on the other hand, coal tar is very cheap. Coal gas lights up Victoria's nightlife, and coal tar is a by-product of gas (cold knowledge: coal tar is a primary carcinogen, but it is also used as a pharmaceutical ingredient). The common practice at that time was to pour the remaining coal tar into the nearby river. August Wilhelm von Hofmann, a German chemist at the Royal College of Chemistry in London, knows a lot about coal tar, which is one of his most famous works. Von Hoffman knows that coal tar contains elements such as carbon, hydrogen and nitrogen, which has great potential for the synthesis of amino compounds. Quinine is an alkaline amine (containing amino groups), which von Hoffman speculated could be formed by combining two naphthylamine molecules with a water molecule, and von Hoffman had already extracted and synthesized a number of amines from coal tar.

As Von Hoffman's assistant, Perkin wanted to impress the teacher, so he wanted to see if he could synthesize quinine. He failed.

In the experiment of trying to synthesize quinine, Perkin oxidized aniline extracted from coal tar with potassium dichromate, leaving a layer of black sticky substance in the flask. Quinine should be colorless. Perkin washed it with alcohol and saw a beautiful purple solution in the flask. He realized that there must have been some kind of chemical reaction, but his goal was still quinine. Later experiments found that the purple solution was easy to dye on clothing fabrics and not easy to clean, and he recorded that the purple was "resistant to the effects of atmosphere, light and soap."

In fact, the key ingredient in the purple solution is aniline violet (Mauveine), the world's first synthetic dye. This is a pure accident discovery, not only the purpose is different, but he later found that aniline has been contaminated with toluidine, the two substances are oxidized together to produce a purple substance.

The original aniline purple dye made in 1906 to celebrate the discovery of purple dye in platinum. ? photo Source: The Board of Trustees of the Science Museum

Shawls dyed with Perkin method exhibited at the International Exhibition in 1862. Photo: blog.sciencemuseum.org.uk

A silk skirt dyed with Perkin's method. Photo: blog.sciencemuseum.org.uk Perkin quickly applied for a patent and immediately asked his father to fund it and set up a factory with his brother to commercialize the dye. This extraordinary business acumen is not born out of thin air. Perkin lives in areas where manufacturing is concentrated, and there is a textile printing and dyeing workshop next to his home. He saw purple clothes in vogue in the 1850s. The lady who loves beauty is obsessed with this beautiful color, and Queen Eugene, the wife of Napoleon III, became a fashion leader because she wore a purple silk dress. Platinum also changed the name of this color to French Mauve, which originally meant purple marshmallow. In May 1857, one of Perkin's business partners wrote to congratulate him, "your color has set off an upsurge among the most powerful women." The advent of fashion also depends on another major feature of aniline purple: cheapness.

More importantly, Perkin's work laid the foundation for the organic chemical industry. This color born with wealth not only came to the family, but also brought human beings into a rich and colorful world. Because the organic chemical industry has developed since then, even though purple is no longer popular, textile dyeing has made great progress. Maybe sometimes chemical products are thought to have some negative meaning, and people prefer natural ones. But medicine, explosives, plastics, chemical fertilizers, and so on, these chemical products are the necessities that really make us leap into modern society. Aniline violet is the first so-called azo dye, and it is one of the earliest chemical products.

Perkin (second from right) and his colleagues from the dye company, second from left, is his brother. At first glance, he looks like a brother. Perkin is actually the seventh at home. (photo Source: blog.sciencemuseum.org.uk/ mauve-mania/ in fact, aniline violet is an extremely complex mixture, two important structures were clearly analyzed by scientists in 1994, and two more important chromophores were discovered in 2008, with a total of 12 compounds.

In order to commemorate Perkin's contribution, the American Chemical Industry Association began to award the Perkin Medal (Perkin Medal) on the 50th anniversary of the discovery of aniline violet in 1906, which is still the highest honor in the chemical field, honoring scientists who have made innovations in the field of applied chemistry and made breakthroughs in business development.

Purple, born noble here also mention why purple is associated with nobility and affluence.

Purple is the color of emperors and royals both at home and abroad. For example, the Imperial Palace in Beijing is called the Forbidden City, and there are also the words "Zitai" (where the emperors live) and "Zizhao" (imperial edicts); while Ziqi comes to the east to say that there are saints coming, which is an auspicious sign. In the West, the rulers of the Byzantine Empire used purple as the royal color, and the empress had children in the purple room (in Chinese mythology, the Emperor of Heaven lived in the Purple Palace), so the word "born in purple" was later extended to indicate birth. The British royal family still uses purple as the etiquette color for special occasions.

The reason is that purple dyes are too rare. The usual colors in this spectrum are difficult to find natural dyes on earth. The earliest use of purple may have been frescoes, and scientists discovered the purple left by humans painting manganese-containing minerals in Neolithic caves. In about 1500-1200 BC, the Phoenicians first found the natural fuchsia dye, called Tyrian purple (π φ φ ρ α porph ú ra), which was extracted and processed from molluscs (bone snails) in the conch. Archaeological evidence in recent years suggests that it may have been first invented by the Minoans of Crete, Greece. But no matter who invented it, it can't change the fact that natural purple dye is difficult to obtain.

Old Pliny, an ancient Roman natural philosopher and naturalist, recorded the production process in his "Natural History". The process is very tedious and will give off a stench (there is also evidence about the stench. There are also bone snails in China's coastal areas. It is recorded in Han Feizi that Duke Huan of Qi likes to wear purple. "I hate the stench of purple." ) and obviously cannot be produced on a large scale-according to some scholars, only 1.4g of dye can be produced from 12000 bone snails, which is only enough to adorn the edges of clothes. Therefore, this color has become a symbol of noble status.

In fact, the color Perkin first discovered for him was called Tyrian purple, which only Roman emperors could wear in the fourth century AD. In the maximum Price Act (Edict on Maximum Prices) of Diocletian in AD 301, a pound of silk dyed with conch sold for as much as 150,000 ancient Roman dinars, which is equivalent to about $3 million in terms of today's purchasing power, according to some scholars.

According to legend, Hercules, the mighty god of ancient Greek mythology, took his dog to woo fairies. As they walked on the beach, the dog bit through a conch (a nautilus rather than a bone snail) and its mouth was dyed purple. Seeing this, the fairy asked to dye a fuchsia robe, which became the source of purple dye. This picture is the work of artist Peter Paul Rubens (Peter Paul Rubens). It was painted around 1636 and is now in the collection of the Prado Museum. ? photo Source: wiki

According to the analysis of modern scholars, the creatures used by the local people are several kinds of bone snails from the Mediterranean region (formerly known as Murex, now belonging to the Muricidae family), such as dye bone snail (Bolinus brandaris), banded bone snail (Hexaplex trunculus), they belong to marine gastropods. The secret of purple comes from the viscous secretion of the dye bone snail, which is oxidized to produce 6pyrine-dibromoindigo, which is a purple ingredient.

6pm-dibromoindigo (photo source: wiki)

Wiki bird dung changed the world over time, smart people around the world found different natural purple raw materials, such as lichen, cochineal, moss, BlackBerry and so on, and developed some synthetic dye technology. By the 1850s, purple was still a fashionable color, although it was no longer so rare, when the source of purple dye in Britain, the textile capital of the world, was Murexide (ammonium Violet urate) to commemorate the fact that the two kinds of bone snails mentioned above were almost extinct in the West after the killing spree of Murex--. The British are extracted from bird droppings, and bird droppings are imported.

In the early 19th century, German scientist and explorer Alexander von Humboldt (Alexander von Humboldt) discovered the fertilizer value of guano (Guano), which is rich in nitrogen, phosphorus and potassium, during his expedition in Peru. The dry natural environment makes the bird dung here the best. He brought the discovery back to Europe, and Europeans soon became aware of the treasure. Business opportunities have also been discovered in Peru, which has been brilliant for a period of time because of bird droppings. If you go a little further, bird droppings had an important impact on capital expansion in the mid-19th century, for which Spain lost the war.

The coast of Peru in the 19th century. Photo: leganerd.com

Poster of seabird manure fertilizer, Photo Source: climateandcapitalism.com as to why people want to extract dyes from bird manure, we have to mention von Hoffman's teacher. Von Hoffmann's teacher, Justus von Liebig, the father of the fertilizer industry, and another German chemist, Friedrich W ö hler (famous for synthetic urea), obtained ammonium violurate (they were not the first to discover the compound) in their study of urea in the 1830s and found that it could dye wool. And their raw material is snake dung, and dye is also a by-product of their research on chemical fertilizer.

In another episode, the Royal College of Chemistry in London (originally proposed by Liebich) is very interested in imported bird droppings, which had received a lot of funding from agriculture in the hope of doing research to increase agricultural production. But the researchers got so little valuable information that they fell into an economic crisis and were incorporated into the Royal Institute of Mining in 1853, now the chemistry department of Imperial College of Technology.

When guano began to be imported into Europe, agriculture, textiles and fashion changed. French manufacturers prepared purple dyes from seabirds, and then Britain and Germany began to dye with ammonium purple urate. However, the dye does not work well in heavily polluted London and is easy to fade after reacting with sulfur. Perkin aniline purple worked better and cheaper, quickly breaking the monopoly. After that, the exploration of color made people wear aniline red (aniine red), aniline blue (aniline blue) and so on. Von Hoffman also produced Hoffman violet (Hofmann's Violet). Their emergence has made purple out of fashion, but the organic chemical industry has changed the world.

references

[1] https://en.wikipedia.org/wiki/William_Henry_Perkin

[2] https://de.wikipedia.org/wiki/August_Wilhelm_von_Hofmann

[3] https://blogs.bl.uk/science/2017/07/william-perkin-and-mauveine.html

[4] https://en.wikipedia.org/wiki/Purple

[5] https://daily.jstor.org/the-accidental-invention-of-the-color-mauve/

[6] https://en.wikipedia.org/wiki/Tyrian_purple

[7] https://www.jstor.org/stable/24877711

[8] https://cuphistory.net/history-of-purple/

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.