Tetrahydrothiophene S,S-dioxide~Tetramethylene sulphone

What are the main users of tetrahydrothiophene, S, S-dioxide and tetramethylene sulfone? Although these two are not described in detail in "Tiangong Kaiwu", their uses can be investigated today.
Tetrahydrothiophene, its gas is very odorous, and it is often a gas odor additive. The cover gas is colorless and odorless, and the leakage is difficult to detect. In addition, people can feel it by its odor when it leaks, so as to prevent problems before they occur. It is widely used in the field of gas safety.
As for S, S-dioxide and tetramethylene sulfone, they are actually the same thing. Tetramethylene sulfone, also known as cyclobutane sulfone. It is an excellent organic solvent and has many applications in petrochemical industry. It can be used for aromatics extraction, extracting aromatics from petroleum fractions, separating aromatics from non-aromatics, and improving oil quality. And because of its stable chemical properties and good thermal stability, it can be used as a reaction medium in high temperature and high pressure reaction systems to assist in the progress of many chemical reactions. And in the field of organic synthesis, it often provides a stable reaction environment for the synthesis of organic compounds, promoting the smooth occurrence of reactions, so it is very important in the chemical industry.

The physical properties of tin tetrachloride ($SnCl_4 $), sulfur dioxide ($SO_2 $) and tetramethylsilane are as follows:
###Tin tetrachloride
Tin tetrachloride is a colorless fuming liquid that is highly volatile at room temperature and pressure. Its odor is pungent and highly corrosive. The melting point of tin tetrachloride is quite low, about -33 ° C, and the boiling point is about 114 ° C. This substance has a density greater than that of water, about 2.226 g/cm ³, and can be miscible with most organic solvents, such as ethanol, ether, etc. In humid air, tin tetrachloride will hydrolyze violently, generating white tin hydroxide smoke. The chemical equation of the reaction is: $SnCl_4 + 4H_2O = Sn (OH) _4? + 4HCl $. Due to its hydrolytic properties, special attention should be paid to moisture protection when storing.
##Sulfur dioxide
Sulfur dioxide is a colorless and irritating gas with a strong sense of suffocation. Its density is higher than air, about 2.9275 g/L, the melting point is -75.5 ° C, and the boiling point is -10 ° C. Sulfur dioxide is soluble in water. At room temperature and pressure, 1 volume of water can dissolve about 40 volumes of sulfur dioxide. After dissolving in water, it forms a sulfurous acid solution. This reaction is reversible, and the chemical equation is: $SO_2 + H_2O H_2SO_3 $. At the same time, sulfur dioxide is also soluble in organic solvents such as ethanol, ether, and chloroform. In addition, sulfur dioxide is easy to liquefy. It can be liquefied into a colorless liquid by cooling it to -10 ° C at room pressure or pressurizing it to about 405.3 kPa at room temperature.
###tetramethylsilane
tetramethylsilane is a colorless, transparent and volatile liquid under normal conditions, with a weak smell. Its melting point is -99 ° C, and its boiling point is only 26.5 ° C, which is highly volatile. The density is small, about 0.646 g/cm ³, lighter than water. Tetramethylsilane is insoluble in water, but it can be miscible with most organic solvents such as hexane, benzene, ether, etc. It is chemically stable, inert to general oxidizing agents and reducing agents, and only reacts under certain harsh conditions. Because its chemical shift is at a high field in hydrogen nuclear magnetic resonance spectroscopy, it is often used as a standard material for nuclear magnetic resonance analysis.

Tetrahydrofuran, S, S-Dioxide | Tetramethylene Sulfone, this is an organic compound, its chemical properties are quite unique, and it has important uses in many fields. The following is a detailed description of Jun.
Tetrahydrofuran, S, S-Dioxide, is a colorless to light yellow transparent liquid at room temperature and pressure, with a weak ether odor. Its chemical properties are stable, but under specific conditions, it can also show a variety of reaction characteristics.
In terms of nucleophilic substitution, the oxygen atom connected to the sulfur atom in its molecular structure has an electron-absorbing effect, which reduces the electron cloud density around the sulfur atom, so it can be used as an electrophilic reagent to react with nucleophilic reagents. For example, when encountering nucleophilic reagents with active hydrogen, such as alcohols and amines, nucleophilic substitution can occur to generate corresponding substitution products. The reaction mechanism is that the nucleophilic reagent attacks the sulfur atom, causing the sulfur-oxygen bond to break and realizing the substitution process.
When it comes to redox properties, although relatively stable, when encountering strong oxidants, such as potassium permanganate, the sulfur atoms in the molecule can be further oxidized to increase their oxidation state and generate higher valence sulfur-containing oxides; when encountering strong reducing agents, a reduction reaction may also occur, changing the oxidation state and structure of the molecule.
In terms of acidity and alkalinity, tetrahydrofuran, S, S-dioxide are weakly basic substances. Due to the presence of lone pairs of electrons in sulfur atoms, protons can be accepted, and when interacted with strong acids, corresponding salts can be formed.
Its physical properties also affect chemical properties, such as good solubility, which can dissolve many organic compounds. This property makes it often used as a solvent in organic synthesis reactions, providing a homogeneous reaction environment for various chemical reactions and promoting the smooth progress of the reaction. From this perspective, the chemical properties of tetrahydrofuran, S, S-dioxide are rich and diverse, and they play an indispensable role in the fields of organic synthesis and materials science, providing an important basis for the realization of many chemical reactions.

In "Tiangong Kaiwu", the preparation method of tetrahydrothiophene, disulfide and tetraformyl urea is described as follows:
tetrahydrothiophene, the preparation method is quite complicated. In ancient times, craftsmen often took sulfur-containing organic raw materials, such as some specific thiols, and compounds with active hydrogen atoms to interact under specific reaction conditions. This reaction needs to be catalyzed in a sealed container at a moderate temperature. The catalysts commonly used are mostly metal salts with specific activities, such as copper salts or zinc salts. Under the action of the catalyst, the raw material molecules undergo rearrangement and cyclization reactions, and after many complex intermediate steps, they finally polymerize into tetrahydrothiophene. When reacting, it is necessary to strictly control the temperature and reaction time. If the temperature is too high, the product will easily decompose, and if the temperature is too low, the reaction rate will be slow, making it difficult to achieve the ideal yield.
The preparation of disulfides often uses sulfur-containing elemental substances or low-cost sulfides as starting materials. For example, sulfur is selected to react with specific organic halides in an alkaline environment. Alkali can promote the nucleophilic substitution of halides, and sulfur ions act as nucleophilic agents to attack the carbon atoms attached to halogen atoms to form sulfur-containing intermediates. This intermediate further reacts with sulfur elemental substances, and the two sulfur-containing groups are connected to each other to form a disulfide structure. In this process, the concentration of the base and the proportion of the reactants are all key factors. A slight error will affect the purity and yield of the product.
The preparation of tetraformylurea usually uses urea and formylation reagents as raw materials. Formalylation reagents are mostly formic acid or its derivatives. In suitable reaction media, such as some polar organic solvents, the amino group of urea and the formylation reagent undergo nucleophilic addition reaction. This reaction requires control of the pH and temperature of the reaction system. Too much acidity or alkalinity is not conducive to the progress of the reaction, and the temperature needs to be maintained within a certain range in order to make the reaction occur smoothly, so that the amino group of urea is gradually replaced by a formyl group, and the final tetraformylurea is obtained. During preparation, the fine regulation of reaction conditions is crucial to the quality and yield of the product.

In the process of using tetraammonium nickel (ⅱ) S, S-dioxide and tetratert-butyl ether, when discussed in the classical Chinese format of "Tiangong Kaiwu", there are indeed many points to be paid attention to.
First of all, tetraammonium nickel (ⅱ) S, S-dioxide, this is a chemical substance, its activity, when used, the first thing to know its physical properties and chemical properties. This substance is easy to react with other substances, such as strong acid and alkali, or violent changes. When it exists, it must choose a cool and dry place, and it is necessary to avoid coexisting with acid and alkali substances in a room to prevent accidents. And because of its toxicity, when handling, be sure to wear protective gear, such as gloves, masks, etc., to avoid skin contact, mouth and nose inhalation, causing damage to the body.
As for tert-butyl ether, it also has unique properties. This substance is flammable, and it is very easy to explode where there is fire or hot topic. In the place where it is used, there must be no open flames, and electrical equipment must also be explosion-proof to prevent static electricity and sparks from causing disasters. At the same time, its volatility should also be paid attention to. It should be operated in a well-ventilated place to disperse the volatile gas in time, so as not to gather in one place and increase the risk of explosion.
When the two are used together, be more cautious. It is necessary to investigate the reaction mechanism of the two in detail first, and determine the method and order of operation according to their characteristics. Do not mix rashly to prevent sudden violent reactions that endanger the safety of people and property. Every step of operation must be done with caution, in accordance with the established rules, and the operator must be familiar with the physical properties and handling methods of the two, so as to be safe. In short, when using these two things, it is necessary to be cautious, to understand the physical properties, and to abide by the laws, so that the relevant things can be done safely and without danger.