The ancients used to classify substances according to certain properties, and tried to trace their origin and the laws of their changes. In the 4th century BC or earlier, China proposed the theory of the five elements of yin and yang, which holds that all things are composed of five basic substances: metal, wood, water, fire, and earth, and that the five elements are formed by the interaction of yin and yang. This statement is a naïve materialist view of nature, which uses the concept of "yin and yang" to explain the two opposing and mutually dissipating material forces in nature, and believes that the interaction between the two is the root cause of all natural phenomena and changes. This is one of the theoretical foundations of Chinese alchemy.

In the 4th century B.C., Greece also put forward the theory of the four elements of fire, wind, earth, and water, as well as the ancient atomic theory, similar to the Five Elements Theory. These naïve ideas of the elements are the germ of the theory of the structure of matter and its change. Later, alchemy appeared in China, and in the Qin and Han dynasties in the 2nd century BC, alchemy was quite popular, and it was spread to Arab countries in the 7th century AD, and merged with ancient Greek philosophy to form Arab alchemy, which was introduced to Europe in the Middle Ages to form European alchemy, and then gradually evolved into modern chemistry.

The guiding ideology of alchemy is to believe that matter can be transformed, and try to artificially synthesize gold and silver or cultivate the elixir of immortality in the alchemy furnace. They purposefully smelted all kinds of substances and conducted experiments. For this purpose, various utensils for the study of material changes are involved, such as sublimators, distillers, mortars, etc., and various experimental methods have also been created, such as grinding, mixing, dissolving, cleaning, burning, melting, sublimating, sealing, etc.

At the same time, the properties of various substances were further classified and studied, especially the properties of mutual reactions. All these laid the foundation for the emergence of modern chemistry, and many of the instruments and methods are still used in today's chemical experiments after being improved. In the course of their experiments, alchemists invented gunpowder, discovered certain elements, made certain alloys, and made and purified many compounds, which we still use today.

The ZTE of Chemistry

Beginning in the 16th century, the boom of industrial production in Europe promoted the establishment and development of medicinal chemistry and metallurgical chemistry, turning alchemy to life and practical application, and then paying more attention to the study of the chemical changes of matter itself. After the establishment of the scientific concept of elements, through the precise experimental study of combustion phenomena, the scientific oxidation theory and the law of conservation of mass were established, and then the law of fixed ratio, the law of multiple ratio and the law of chemical synthesis were established, which laid the foundation for the further scientific development of chemistry.

At the beginning of the 19th century, the modern atomism was established, which prominently emphasized the mass of the atoms of various elements as its most basic feature, and the introduction of the concept of quantity was a major difference from the ancient atomism. Modern atomic theory has provided a rational explanation of the chemical knowledge and theories of the time, and has become a unified theory for explaining chemical phenomena. The molecular hypothesis was proposed, and the atomic and molecular theory was established, which laid the foundation for the study of the structure of matter. After Mendeleev discovered the periodic law, he not only initially formed a system of inorganic chemistry, but also formed a chemical theory system together with the theory of atoms and molecules.

Through the analysis of minerals, many new elements have been discovered, and the experimental verification of atomic and molecular theories has led to the establishment of a system of classical chemical analysis. The synthesis of oxalic acid and urea, the generation of the concept of atomic valence, the establishment of the theory of hexacyclic structure of benzene and the tetrahedron of carbon valence bonds, the splitting of tartaric acid into optical isomers, and the discovery of molecular asymmetry have led to the establishment of organic chemical structure theory, which has deepened people's understanding of the nature of molecules and laid the foundation of organic chemistry.

In the second half of the 19th century, physical theories such as thermodynamics were introduced into chemistry, which not only clarified the concepts of chemical equilibrium and reaction rate, but also quantitatively judged the direction and conditions of material transformation in chemical reactions. The theoretical foundations of solution theory, ionization theory, electrochemistry and chemical kinetics were established successively. The birth of physical chemistry has raised chemistry from theory to a new level.

When it comes to sulfuric acid, many people think that it is a modern chemical product, but it has actually been produced in ancient times.

The alchemy anthology "Yellow Emperor Jiuding Shendan Sutra" compiled by the Tang Dynasty in China includes the "gold mining method" of the alchemist Hu Gangzi (also known as Hu Gangzi) in the last years of the Eastern Han Dynasty (AD 25~220), which includes the "method of refining stone gall to extract the essence". The so-called "stone gall" refers to the pentahydrate crystal of copper sulfate (CuSO4.5H2O), which is still called "gall alum" in China, because it is blue, the same as gall. The "refining stone gallbladder extraction method" is to distill bile alum to produce sulfuric acid. Because the pentahydrate crystals of copper sulfate are decomposed by heat to form copper oxide (CuO), sulfur trioxide (SO3) and water. Sulfur trioxide is dissolved in water to form sulfuric acid, which is expressed by modern chemical equations:

CuSO4.5H2O→CuO+SO3+5H2O

SO3+H2O→H2SO4

The original text of this passage is as follows: "Make two square-headed furnaces with clay bases, two feet apart, and make a hole in the side of each side of the fine mud, and also mud on the surface and inside, so that the fine is fumigated, and the dry is made, and the copper plate in the furnace is opened, and the mud is fixed, that is, the dense mud; In a furnace, the charcoal burns stone gall to make smoke, and the essence of it is all into the copper plate. But the fire in the furnace is cold, and it is open and appointed. into ten thousand medicines, all medicines are gods". The "earth" here is "adobe"; "Fine mud in between" is to seal the gap with fine clay; "Seifu" is slowly heated; "Smoke" refers to the mist gas produced by the combination of sulfur trioxide and water vapor; The use of "copper discs" is obviously to prevent the corrosion of dilute sulfuric acid on the receiver.

That is to say, around the 2nd century AD, China has created the "earth chamber method" to produce sulfuric acid. But this method has not been promoted in our country.

In the 13th century, Albertus Magnus (1193~1280), a German Catholic priest in Europe, mentioned in his writings that the distillation of alum to produce sulfuric acid. Alum is a heptahydrate crystal of ferrous sulfate (FeSO4.7H2O), named for its green color. The chemical process of distilling green alum to produce sulfuric acid is the same as that of distilling bile alum. Therefore, the Europeans called sulfuric acid alum oil in the Middle Ages.

According to the works of the 10th-century Persian alchemist al-Rhazes (al-Rhazes 845~930), translated by Europeans, it is also mentioned that the distillation of green alum is used to produce sulfuric acid.

In the late Middle Ages, European capitalist production relations gradually grew on the basis of the development of productive forces within the feudal system, and in the 18th century, European manual workshops transitioned to large-scale machine production, and production promoted the need for sulfuric acid in all aspects of society.

In 1736, the Englishman Ward (Joshua (1685~1761) established the "Great Vitriol Works" in Twickenham-on-Thames, England, and began to produce sulfuric acid on a large scale.

Wade was a charlatan, convicted of attempting to enter the British Parliament in 1717, fled to France, and returned to England in 1733 after being pardoned, where he practiced medicine in the manufacture of saltpeter and porcelain in Twickenham. He thought Glauber's Salts had extraordinary benefits in medicine and wanted to make it. Glauber salt, which refers to sodium sulfate, was discovered in 1625 by the German chemist Glauber (Johann Rudolph (1604-1670) in mineral water near Austria*. He distilled mineral water to obtain its decahydrate crystals (Na2SO4.10H2O), first used it as a laxative, and realized that it could be prepared by the action of table salt and sulfuric acid, and was a by-product of the preparation of hydrochloric acid.

In order to make Glauber salt, Walder made sulfuric acid. He used a mixture of burning sulfur and saltpeter to make sulfuric acid, a method first created by the Dutch inventor Drebbel (Cornelius 1572~1633). The French pharmacist Lemery (Nicolas 1645~1715) mentioned this method in his work published in 1675~1690, in which a mixture of sulfur and saltpeter was burned in a large inverted funnel. Therefore, this method is also called the bell method. Wade may have learned this method while living in St. Grermain, near Paris, while on the run from crime to France.

Wade's equipment for manufacturing sulphuric acid is spherical wide-mouth glass bottles with a capacity of 40-50 gallons (UK volume unit, 1 gallon = 4.546L). During the operation, a small amount of water is placed in the bottle, and a small stoneware jar is placed, an iron plate is placed on the tank, a mixture of sulfur and saltpeter is placed in it, the mixture is ignited with a small red hot shovel, the bottle mouth is corked tightly, and the device is repeated after a period of time until the desired concentration of sulfuric acid is reached.

Due to the harmful fumes produced in the production and the pollution of the environment, Wade's sulphuric acid manufacturing workshop was opposed by the local population, and in 1740 it moved to Richmond in the north of England, and in 1749 it was patented in England. In order to keep his manufacturing secret, Wald hired Welsh workers who did not speak English. Still, he told the secret to his friend Page, John, and it was made public after his death in 1763. But how glassblowers made such large-capacity glassware at the time was a mystery.

About 100 spherical wide-mouth glass bottles were used in Wade's sulphuric acid factory, which brought the price of sulphuric acid down to 2 shillings and 6p per pound (British currency). This is equivalent to the previous price per ounce, where 1 pound equals 16 ounces, which means that the price of sulphuric acid has dropped to 1/16 of the original price.

However, Wade's equipment and methods of operating for the production of sulphuric acid were soon replaced by the lead chamber method created by another Englishman, Roebuck (John 1718-1794).

Robock was a physician and physician who was elected a Fellow of the Royal Society in 1764. In the 1840s, he lived in the English industrial city of Birmingham, where he practiced medicine privately, founded an ironworks, and recycled gold and silver from jewellery scrap. In 1746, he and his collaborator Garbett (Samuel 1717~1805) needed sulfuric acid to dissolve impurities in the recovery of gold and silver, and learned from chemistry textbooks that lead can resist the corrosion of sulfuric acid, so they made a frame of wood and used lead plates as walls to create a cubic lead chamber of 6 feet (British length unit, 1 foot = 0.3048m) on each side. During the operation, sulfur and saltpeter are placed in an iron spoon, ignited and put into an iron plate in the lead chamber, so that the sulfur oxide gas produced is absorbed by the water sprayed on the wall of the lead chamber in advance to form sulfuric acid, and sulfur and saltpeter are continuously added, and the acid is taken out about once every 4 weeks, and then put into a glass container for heating and concentration.

By 1749, Robock had founded the "Prestonpans Vitriol Co." in Prestonpans, Scotland, where he built larger and more lead chambers, employing 50 workers and working day and night shifts, so that the production of sulphuric acid from pounds to tons was not only for British use, but also exported to continental Europe.

In order to keep the production technology secret, Robuk built a high wall around his workshop and required every worker to swear an oath of secrecy. But under the temptation of money, the walls were broken and the oath was abandoned. Skey Samuel, a wealthy chemical manufacturer in Bewdley, bought off a worker to learn about the construction and operation of the lead chamber, and built a 10-foot cube on each side to make sulfuric acid. Subsequently, lead chambers were built in London and elsewhere, as well as in some parts of France. Lead chambers were built larger and more numerous. In 1805, a sulphuric acid manufacturing site on Burnt Island, England, had 360 lead chambers, each measuring 192 cubic feet. Chaptal (Jean Antoine Claude (1756~1832), a professor of chemistry at the University of Montpellier in France and a wealthy industrialist, proposed that the largest lead chamber should be 25 feet on each side and 15 feet high, but he built a large lead chamber 80 feet long, 40 feet wide and 50 feet high, which collapsed after 18 months of use.

In order to reduce the cost of sulfuric acid production, some manufacturers are gradually replacing sulfur with pyrite or chalcopyrite and other sulfur-containing minerals. Some manufacturers are also making improvements in their production equipment, such as spraying water vapor into the lead chamber instead of spraying water into the lead chamber wall, and placing a furnace that burns sulphur or other sulfur-containing minerals instead of burning in the lead chamber. In this way, the production of sulfuric acid gradually shifts from intermittent to continuous, so that the output of sulfuric acid increases greatly. By 1878, annual production of sulfuric acid in Europe had reached millions of tons.

For a time, sulphuric acid manufacturers believed that the purpose of adding saltpeter to the combustion of sulphur in the sulphuric acid manufacturing process was to produce oxygen, and to oxidize sulphur dioxide to sulphur trioxide, so they no longer supplied air to the lead chamber. In 1806, two chemists, Desormes (Charles Bernard (1777~1862) and Clement Nicolas (1779~1841), observed that the mixed gas of sulfur dioxide and nitrogen dioxide was passed into the lead chamber to form white crystals, and the white crystals were treated with water to form sulfuric acid and re-release nitric oxide gas, so it was determined that the sulfur dioxide was not directly oxidized by oxygen in the lead chamber. Rather, it forms an intermediate product with nitrogen oxides, and the whole process of forming sulfuric acid is a cyclic process. This has led to the research of many chemists, and it has been determined by many people that sulfur dioxide and nitric oxide, oxygen and water in the lead chamber form nitroso sulfuric acid (ONOSO2H), and nitroso sulfuric acid reacts with water to form sulfuric acid and release nitrogen oxides, which can be expressed by the following chemical equations:

2NO+O2→2NO2

2SO2+3NO2+H2O→2ONOSO2OH+NO

2ONOSO2OH+H2O→2H2SO4+NO+NO2

In other words, nitrogen oxide is actually a catalyst for oxygen to oxidize SO2 to SO3.

As a result, the amount of expensive saltpeter used in the lead chamber method of sulfuric acid is reduced, and the amount of air supplied is increased, so that the cost is reduced again. By the beginning of the 20th century, saltpeter was basically no longer used, and ammonia was used, because ammonia, in the presence of a catalyst such as platinum, could react with oxygen in the air to form nitrogen oxides. This reaction is:

4NH3+5O2→4NO+6H2O

Since nitrogen oxides can be reused, the question arises as to how to recover these nitrogen oxides. In 1827, the famous French chemist Gay-Lussac (Joseph Louis 1778~1850) proposed to set up a tower behind the lead chamber, which was filled with coke, and the gas released in the lead chamber was passed from the bottom of the tower. However, nitrogen oxides cannot be completely absorbed, because nitric oxide is not easily soluble in sulfuric acid and does not react chemically, while nitrogen dioxide is not easily soluble in concentrated sulfuric acid and only soluble in dilute sulfuric acid. In order to re-release the nitrogen oxides so that they can be re-utilized in the lead chamber, it is not economical to initially dilute the acid of the nitrogen absorbing oxides with water, which will dilute the resulting sulfuric acid and reconcentrate it. As a result, the tower designed by Gelusak was not put into practical use for a long time. This tower was later named the Gelysak Tower.

In 1859, a British plumber Glover (John 1817~1902) proposed to set up a tower between the furnace and the lead chamber where the sulfur was burned, so that the high-temperature sulfur dioxide gas could flow upward, and meet the nitrogenous sulfuric acid sent from the Gelusak tower at the top of the tower, so that the nitrogen oxides in it would be released by heat and enter the lead chamber. This not only fully recovers the nitrogen oxides, but also releases the nitrogen oxides that were absorbed in the Gelusak tower. The tower, which was later named the Glover Tower, was soon used in practical production, where an ordinary worker perfected the design of a famous chemist, and became famous in the manufacture of sulfuric acid.

Since then, sulfuric acid manufacturers have made a series of improvements to the lead chamber.

The lead chamber is no longer cubic, because the cube will form corners, the material may be stagnant in these corners, the flow speed of the air flow is very slow, and the repeated contact between the gas phase and the liquid phase of the tiny droplets is very poor, so it is gradually transformed into a cylindrical or truncated conical shape, so that the shape becomes a tower shape.

The lead chamber is no longer empty, but filled with porcelain beads. This increases the surface of the reactants.

The frame is no longer wood, but steel, and even the lead plates have been replaced by iron and steel, which are just as resistant to sulfuric acid corrosion as lead, and the lining is made of acid-resistant bricks or orthoclase, which strengthens the corrosion resistance.

In this way, the lead chamber method becomes the tower method, but the chemical principle of sulfuric acid manufacturing is still the same.

The chemistry of the contact method for the production of sulfuric acid is different. The contact method, also known as the catalyst method or catalytic method, began in 1831. In that year, Phillips, peregrine, a vinegar merchant in Bristol, a port city in southwestern England, England, submitted a patent application to the government for a project to "save the cost of saltpeter and alum lead chambers", which used platinum powder as a catalyst to oxidize sulfur dioxide directly by oxygen to sulfur trioxide, and then dissolved sulfur trioxide in water to form sulfuric acid. However, this method was not immediately put into actual production because the platinum powder quickly became ineffective due to the impurities entrained in the sulfur dioxide. It was not until 1875 that a chemist born in Germany and living in the United Kingdom for a long time, Messel (Rudolph (1848-1920), proposed to first purify sulfur dioxide and oxygen, which can make platinum powder effective for a certain period of time, so that sulfur dioxide and oxygen can be made into SO3 catalyzed by platinum asbestos, and oleum is made by absorption of ordinary sulfuric acid. In 1881, Squires W.S., a British sulfuric acid manufacturer, applied for a patent for this method and built a factory for production. Maicel was involved.

Winkler (Clemens Alexander, 1838~1904), a German chemist who discovered the element germanium, also conducted experiments on the synthesis of SO3 by oxygen in the presence of platinum and oxygen in 1875.

But platinum's high value and poisoning have prompted sulfuric acid makers and chemists to look for cheaper catalysts. By the 20s of this century, vanadium oxides, iron oxides and other catalysts appeared. Vanadium catalysts are almost always used in modern contact sulfuric acid manufacturing.