Introduction and functions of solvents

A solvent is a liquid (gas, or solid) that can dissolve a solid, liquid or gas solute (both solvent and solute are Can be solid, liquid, gas), and then become a solution. The most common solvent in daily life is water. The so-called organic solvents are organic compounds containing carbon atoms. Solvents usually have relatively low boiling points and are easy to evaporate. Or it can be removed by distillation, leaving the dissolved material behind. Therefore, the solvent cannot react chemically with the solute. They must be inert. Solvents extract soluble compounds from mixtures, the most common example of which is brewing coffee or tea with hot water. Solvents are usually clear, colorless liquids, and most of them have a distinctive odor.

1. Introduction

The concentration of the solution depends on the dissolution The amount of substance in the solvent. Solubility is the maximum amount of substance that a solvent can dissolve at a specific temperature. Organic solvents are mainly used for dry cleaning (such as tetrachlorethylene), as paint thinners (such as toluene, turpentine), as nail polish remover or glue removal (such as acetone, methyl acetate, ethyl acetate), and for rust removal (such as hexane). ), used as detergent (lemon essence), perfume (alcohol) and chemical synthesis (Chemical synthesis).

It is customary to call gases and solids solutes, and liquids called solvents.

2. Solution Concentration

Solvents and solutes can be roughly divided into polar groups (hydrophilic) and non-polar groups (hydrophobic). Polarity can be determined by measuring the dielectric constant or dipole moment of a substance.

3. Function

Introduction

<p style="text-align: starKetones, aromatic hydrocarbons, hydrogenated hydrocarbons, terpene hydrocarbons, halogenated hydrocarbons, heterocyclic compounds, nitrogen-containing compounds and sulfur-containing compounds, etc., most of which have certain toxicity to the human body.

It is found in coatings, adhesives, lacquers and cleaners. Organic solvents such as styrene, perchlorethylene, trichlorethylene, ethylene glycol ether and triethanolamine are often used.

Organic solvents are a type of organic compounds that can dissolve some water-insoluble substances (such as grease, wax, resin, rubber, dyes, etc.). They are characterized by being soluble at normal temperatures and pressures. Liquid state, with greater volatility. During the dissolution process, the properties of the solute and solvent do not change.

Type

Type of organic solvent: organic solvent There are many types, which can be divided into 10 categories according to their chemical structures: ① Aromatic hydrocarbons: benzene, toluene, xylene, etc.; ② Aliphatic hydrocarbons: pentane, hexane, octane, etc.; ③ Alicyclic hydrocarbons: cycloaliphatic hydrocarbons: Hexane, cyclohexanone, toluene cyclohexanone, etc.; ④ Halogenated hydrocarbons: chlorobenzene, dichlorobenzene, dichloromethane, etc.; ⑤ Alcohols: methanol, ethanol, isopropanol, etc.; ⑥ Ethers: ether, cyclohexanone, etc. Oxygen propane, etc.; ⑦ Esters: methyl acetate, ethyl acetate, propyl acetate, etc.; ⑧ Ketones: acetone, methyl butanone, methyl isobutyl ketone, etc.; ⑨ Diol derivatives: ethylene glycol monomethyl Ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, etc.; ⑩ Others: acetonitrile, pyridine, phenol, etc.

(1)Acidic Solvent: This type of solvent has a stronger ability to donate protons than to accept protons, such as formic acid, sulfuric acid, etc.

(2) Alkaline solvent: A solvent with a strong ability to accept protons, such as ethylenediamine (NH2CH2CH2NH2), etc.

(3) Amphoteric solvents: solvents that have equal proton-giving and proton-accepting capabilities, such as water, methanol, ethanol, etc.

(4) Inert solvent: a solvent that can neither donate nor accept protons, such as benzene, chloroform, etc.

; text-align: left;”>