Unlike inorganic solvents, most organic solvents can invade the human body through the respiratory tract, skin mucosa, and digestive tract, and have the characteristics of accumulation and fat-soluble penetration. They easily penetrate biological cell membranes. Long-term low-dose exposure can cause organic damage to the nervous system, blood system, liver and kidney metabolic system. It is the core control object of occupational health control, hazardous chemical safety management, and atmospheric VOCs management. The application of pure organic solvents in industrial scenes accounts for a very low proportion, and most of them exist in mixed solvent systems. Therefore, the national standard system specifically defines the mixed solvent judgment standard to provide a quantitative basis for on-site compliance control. Unlike inorganic solvents, the vast majority of organic solvents can invade the human body through the respiratory tract, skin mucosa, and digestive tract, and have the characteristics of accumulation, fat-soluble penetration, easy to penetrate biological cell membranes, and long-term low-dose exposure can cause organic damage to the nervous system, blood system, liver and kidney metabolic system. It is the core control object of occupational health control, hazardous chemical safety management, and atmospheric VOCs management. The application of pure organic solvents in industrial scenes accounts for a very low proportion, and most of them exist in mixed solvent systems. Therefore, the national standard system specifically defines the mixed solvent judgment standard to provide a quantitative basis for on-site compliance control.

Second, the underlying control logic for the classification determination of organic solvent mixtures Second, the underlying control logic for the classification determination of organic solvent mixtures

The national standard system uses the national standard system to 5% by mass and 5% by mass as the critical threshold to divide the mixed organic solvents into three levels. The threshold is not an empirical value, but based on the scientific quantification of occupational exposure risk, vapor diffusion concentration, and explosion risk probability. The core purpose is to solve the industry pain points of mixed solvents "toxic superposition, vague risk, and unfounded control". The three-level division of mixed organic solvents is a critical threshold. The threshold is not an empirical value, but a scientific quantification based on occupational exposure risk, vapor diffusion concentration, and explosion risk probability. The core purpose is to solve the industry pain points of mixed solvents "toxic superposition, vague risk, and unfounded control".

The determination core of the first type of organic solvent mixture is the determination core of the first type of organic solvent mixture is dominant risk of highly toxic substances , as long as the quality of a class of highly toxic solvents in the mixed system exceeds 5%, the whole is controlled according to the high-risk system. The reason is that benzene, carbon tetrachloride, trichloroethylene and other solvents have irreversible carcinogenic, teratogenic and mutagenic properties, and small amounts of long-term exposure can cause serious occupational diseases, and there is no safe exposure threshold., As long as the quality of a class of highly toxic solvents in the mixed system exceeds 5%, the whole is controlled according to the high-risk system. The reason is that benzene, carbon tetrachloride, trichloroethylene and other solvents have irreversible carcinogenic, teratogenic and mutagenic properties, and small amounts of long-term exposure can cause serious occupational diseases, and there is no safe exposure threshold.

The second type of organic solvent mixture is the most mainstream system in industry, and the second type of organic solvent mixture is the most mainstream system in industry. It belongs to the low toxicity superposition risk system low toxicity superposition risk system. It does not contain a type of highly toxic solvent, but the total proportion of the second type of solvent exceeds 5%. This type of system has no strong carcinogenicity, but there are neurotoxicity, mucosal irritation and chronic accumulation damage, which is the most easily ignored source of occupational hazards in conventional production scenarios., does not contain a type of highly toxic solvent, but the total proportion of the second type of solvent exceeds 5%. This type of system has no strong carcinogenicity, but there are neurotoxicity, mucosal irritation and chronic accumulation damage, which is the most easily ignored source of occupational hazards in conventional production scenarios.

The third type of organic solvent mixture belongs to a low-risk petroleum-based system. The components are mainly light hydrocarbon mixtures. The acute toxicity is extremely low, the chronic accumulation risk is weak, and there is only a slight anesthesia and explosion risk. The control focuses on fire prevention and explosion prevention, and does not require strict occupational special control. The three-level grading system realizes the "risk classification, classification policy, and precise control" of industrial solvents, completely avoiding the resource waste and control loopholes of the one-size-fits-all management model. The third type of organic solvent mixture belongs to a low-risk petroleum-based system. The components are mainly light hydrocarbon mixtures. The acute toxicity is extremely low, and the chronic accumulation risk is weak. There is only a slight anesthesia and explosion risk. The control focuses on fire prevention and explosion prevention, and does not require strict occupational special control. The three-level grading system realizes the "risk classification, classification policy, and precise control" of industrial solvents, completely avoiding the resource waste and control loopholes of the one-size-fits-all management model.

III. Deep analysis of the structure-activity relationship of organic solvents based on chemical structures III. Deep analysis of the structure-activity relationship of organic solvents based on chemical structures

The solubility, volatilization rate, toxicity mechanism, and explosion characteristics of organic solvents are completely determined by the molecular chemical structure. Different structural categories form differentiated industrial application scenarios and safety risk levels. Its structure-activity law is the core basis for solvent selection, process design, and risk prevention and control. The solubility, volatilization rate, toxicity mechanism, and explosion characteristics of organic solvents are completely determined by the molecular chemical structure. Different structural categories form differentiated industrial application scenarios and safety risk levels. Its structure-activity law is the core basis for solvent selection, process design, and risk prevention and control.

1. Chain alkanes (linear/branched chain hydrocarbons) 1. Chain alkanes (linear/branched chain hydrocarbons) : Represented by pentane, hexane, heptane, the molecule is a pure hydrocarbon saturated structure, with extremely low polarity and weak solubility. It only has the ability to dissolve non-polar substances such as grease and mineral oil. The biggest feature of this type of solvent is that it is mildly toxic, but n-hexane and other components have specific peripheral neurotoxicity. Long-term exposure can easily cause numbness in the limbs and motor nerve damage. It is the core cause of high occupational poisoning in the electronic wiping and printing industries. At the same time, its flash point is extremely low and the evaporation rate is fast, which is a typical representative of industrial light flammable and explosive solvents.: Represented by pentane, hexane, heptane, the molecule is a pure hydrocarbon saturated structure, with extremely low polarity and weak solubility, and only has the ability to dissolve non-polar substances such as grease and mineral oil. The biggest feature of this type of solvent is mild toxicity, but n-hexane and other components have specific peripheral neurotoxicity. Long-term exposure can easily cause limb numbness and motor nerve damage, which is the core cause of high occupational poisoning in electronic wiping and printing industries. At the same time, its flash point is extremely low and the evaporation rate is fast, which is a typical representative of industrial light flammable and explosive solvents.

2. Cyclic hydrocarbons 2. Cyclic hydrocarbons : Contains cyclic structural compounds such as cyclohexane, turpentine, and cyclic olefins. Compared with chain alkanes, the cyclic molecular structure is more stable and has a wider dissolution range, which can be adapted to dissolve in some resin materials. The overall toxicity of cyclic alkanes is lower than that of aromatic hydrocarbons, but the cyclic unsaturated structure is prone to oxidative metabolism in the body, resulting in irritating metabolites. At the same time, the vapor density is high, and it is easy to gather in low-lying places. The risk of explosion is higher than that of ordinary chain alkanes.: Contains cyclic structural compounds such as cyclic hexane, turpentine, and cyclic olefins. Compared with chain alkanes, the cyclic molecular structure is more stable The overall toxicity of naphthenes is lower than that of aromatic hydrocarbons, but the cyclic unsaturated structure is prone to oxidative metabolism in the body, generating irritating metabolites. At the same time, the vapor density is high, and it is easy to accumulate in low-lying places. The risk of ignition is higher than that of ordinary chain alkanes.

3. Ester solvents 3. Ester solvents : Ethyl acetate, isopropyl acetate, and butyl acetate are the core industrial categories. They belong to polar neutral solvents. They have both polar and non-polar solubility and are suitable for dilution and dissolution of resins, coatings, and inks. They are the most widely used green solvents in fine chemicals. Ester molecules contain ester functional groups, which can be slowly hydrolyzed at room temperature to generate corresponding alcohols and organic acids without strong accumulation toxicity; however, their common shortcomings are rapid volatilization, low flash point, and hydrolysis products will slightly enhance the corrosiveness of the system. At the same time, high-concentration vapor has anesthesia, which is easy to cause acute discomfort such as dizziness and fatigue. Among them, isopropyl acetate has balanced solubility and moderate volatilization rate. It is the mainstream environmentally friendly ester solvent in the paint and pharmaceutical industries.: With ethyl acetate, isopropyl acetate, and butyl acetate as the core industrial categories, it belongs to the polar neutral solvent, which has both polar and non-polar solubility. It is suitable for dilution and dissolution of resins, coatings, and inks. It is the most widely used green solvent in fine chemical industry. Ester molecules contain ester-based functional groups, which can be slowly hydrolyzed at room temperature to generate corresponding alcohols and organic acids, without strong accumulation toxicity; however, their common shortcomings are fast volatilization, low flash point, and hydrolyzed products will slightly improve the corrosiveness of the system. At the same time, high-concentration steam has anesthesia, which is easy to cause acute discomfort such as dizziness and fatigue. Among them, isopropyl acetate has balanced solubility and moderate volatilization rate, and is the mainstream environmentally friendly ester solvent in the coating and pharmaceutical industries.

4. Aromatic hydrocarbons 4. Aromatic hydrocarbons : Benzene, toluene, xylene, styrene are typical representatives, and the molecule contains a benzene ring conjugated structure with strong solubility. It is a powerful solvent for coatings, rubber, and resins, and is also the most industrially toxic solvent category. The benzene ring structure has strong biological toxicity, among which benzene can directly inhibit the hematopoietic function of human bone marrow and induce malignant blood diseases such as leukemia; although toluene and xylene are less toxic than benzene, long-term exposure will damage the central nervous system and liver and kidney metabolic system, which belongs to the volatile toxic and harmful substances under key control.: Benzene, toluene, xylene, and styrene are typical representatives. The molecule contains a benzene ring conjugated structure with strong solubility. It is a powerful solvent for paints, rubber, and resins, and is also the solvent category with the highest industrial toxicity. The benzene ring structure has strong biological toxicity, among which benzene can directly inhibit the hematopoietic function of human bone marrow and induce malignant blood diseases such as leukemia; although toluene and xylene are less toxic than benzene, long-term exposure will damage the central nervous system and liver and kidney metabolic system

5. Alcohol solvents 5. Alcohol solvents : methanol, ethanol, isopropanol, n-butanol, etc., the molecule contains hydrophilic hydroxyl groups, with strong polarity and good water solubility, which can be adapted to the dissolution of polar materials, and most alcohol solvents can be biologically metabolized and weakly accumulative. The differentiated risk is that methanol has specific toxicity of the optic nerve, and a small amount of ingestion or long-term inhalation can cause irreversible visual damage; isopropanol and n-butanol are mainly at risk of mucosal stimulation and central anesthesia, and the industrial safety is relatively excellent.: Methanol, ethanol, isopropanol, n-butanol, etc., the molecule contains hydrophilic hydroxyl groups, with strong polarity and good water solubility, which can be adapted to the dissolution of polar materials, and most alcohol solv Differentiated risk lies in the optic nerve-specific toxicity of methanol, which can cause irreversible visual damage by ingestion or long-term inhalation; isopropanol and n-butanol are mainly at risk of mucosal stimulation and central anesthesia, and the industrial safety is relatively excellent.

6. Ketone solvents 6. Ketone solvents : acetone, methyl ethyl ketone, etc., the carbonyl structure gives it a strong solubility adaptability, compatible with polar and non-polar materials, strong solubility and controllable volatilization rate. Ketone solvents have extremely low overall toxicity and fast metabolism. They are the core environmental protection solvents for industrial replacement of benzene series. Only high concentration exposure can cause respiratory irritation and slight anesthesia reaction, without chronic accumulation damage.: Acetone, methyl ethyl ketone, etc., the carbonyl structure gives it a strong solubility adaptability, compatible with polar and non-polar materials, strong solubility and controllable volatilization rate. Ketone solvents have extremely low overall toxicity and fast metabolic rate. They are the core environmental protection solvents for industrial replacement of benzene series. Only high-concentration exposure can cause respiratory tract irritation and mild anesthesia reaction without chronic accumulation injury.

7. Halogenated hydrocarbons 7. Halogenated hydrocarbons : Carbon tetrachloride, trichloromethane, trichloroethylene and other halogen-containing substituted hydrocarbons are powerful solvents for industrial cleaning and degreasing. The introduction of halogen atoms greatly improves the chemical stability and flame retardancy of solvents, but at the same time produces extremely strong liver and kidney toxicity and carcinogenic risk. Most halogenated hydrocarbons are included in the list of new pollutants under key control. Their metabolites can damage liver cells and destroy kidney function. Some components have clear human carcinogenicity and have been gradually restricted to civilian applications.: Carbon tetrachloride, trichloromethane, trichloroethylene and other halogen-containing substituted hydrocarbons are powerful solvents for industrial cleaning and degreasing. The introduction of halogen atoms greatly enhances the chemical stability and flame retardancy of solvents, but at the same time produces extremely strong liver and kidney toxicity and carcinogenic risks. Most halogenated hydrocarbons are included in the list of key new pollutants under control, and their metabolites can damage liver cells and damage kidney function. Some components have clear human carcinogenicity and have been gradually restricted to civilian applications.

8. Aldoxides, ethers, glycol and nitro hydrocarbons 8. Alaldehyde, ether, diol and nitrohydrocarbons : Aldides are represented by formaldehyde and acetaldehyde, which are highly irritating, highly allergenic, and genotoxic; ether solvents evaporate extremely fast, have extremely low flash point, and have strong electrostatic sensitivity, which is easy to cause flash explosion accidents; diol solvents have strong water solubility, high boiling point, weak volatilization, and low occupational toxicity, and are mostly used for high boiling point moisturizing and film-forming aids; nitrohydrocarbons have poor chemical stability, both toxicity and explosive instability, and have extremely narrow industrial application scenarios. They are only used for special synthesis processes.: Aldides are represented by formaldehyde and acetaldehyde, which are highly irritating, highly allergenic, and genotoxic; ether solvents evaporate extremely fast, have extremely low flash point, and have strong electrostatic sensitivity, which is easy to cause flash explosion accidents; diol solvents have strong water solubility, High boiling point, weak volatilization, low occupational toxicity, mostly used for high boiling point moisturizing and film-forming additives; nitro hydrocarbons have poor chemical stability, both toxicity and explosive instability, and have extremely narrow industrial application scenarios. They are only used in special synthesis processes.

4. In-depth interpretation of three-level classification control based on occupational toxicity (core differentiated cognition) 4. In-depth interpretation of three-level classification control based on occupational toxicity (core differentiated cognition)

The classification of national standard one, two, and three types of organic solvents, and the classification of national standard one, two, and three types of organic solvents, is by no means a simple toxicity ranking, but based on "carcinogenicity, accumulation, target organ damage, irreversible risk" The occupational risk classification management and control system is by no means a simple toxicity ranking, but based on "carcinogenicity, accumulation, target organ damage, irreversible risk" The occupational risk classification management and control system directly corresponds to the differentiated requirements of enterprise safety management, occupational physical examination, on-site protection, and emission control, and is the core basis for industrial site compliance management., directly corresponds to the differentiated requirements of enterprise safety management, occupational physical examination, on-site protection, and emission control, and is the core of industrial site compliance management According to.

1. The first type of organic solvent: high toxicity irreversible control class 1. The first type of organic solvent: high toxicity irreversible control class

All of these solvents belong to this class of solvents. All belong to highly toxic carcinogenic, teratogenic, mutagenic substances highly toxic carcinogenic, teratogenic, mutagenic substances . There is no safe exposure threshold, and a small amount of long-term exposure can cause irreversible organic lesions. It is a highly toxic substance under national key control. Among them, benzene is a type of carcinogen, which targets to damage the human hematopoietic system; carbon tetrachloride, trichloromethane, tetrachloroethane and other halogenated hydrocarbons target to damage the liver and kidneys, inducing organ fibrosis and carcinogenesis; carbon disulfide has extremely strong neurotoxicity and vascular toxicity, which can cause systemic metabolic damage., Without a safe exposure threshold, a small amount of long-term exposure can cause irreversible organic lesions, which is a highly toxic Benzene is a type of carcinogen that targets and damages the human hematopoietic system; carbon tetrachloride, trichloromethane, tetrachloroethane and other halogenated hydrocarbons target liver and kidney damage, inducing organ fibrosis and carcinogenesis; carbon disulfide has extremely strong neurological and vascular toxicity, which can cause systemic metabolic damage.

At the level of industrial control, a type of solvent is strictly prohibited from being used in civilian painting, food contact, and daily cleaning scenarios. The workplace must realize closed operation, negative pressure ventilation, and real-time online monitoring. Operators need special project pre-job physical examination and quarterly re-inspection. It belongs to the highest level of occupational hazard control objects. At present, most industries have gradually realized replacement elimination. At the level of industrial control, a type of solvent is strictly prohibited from being used in civilian painting, food contact, and daily cleaning scenarios. The workplace must realize closed operation, negative pressure ventilation, and real-time online monitoring. Operators need special project pre-job physical examination and quarterly re-inspection. It belongs to the highest level of occupational hazard control objects. At present, most industries have gradually realized replacement elimination.

2. The second type of organic solvents: industrial mainstream, chronic accumulation control class 2. The second type of organic solvents: industrial mainstream, chronic accumulation control class

The second type of solvent is the largest category of organic solvents in industrial applications, covering core materials such as esters, alcohols, ketones, common halogenated hydrocarbons, and benzene derivatives. The second type of solvent is the largest category of organic solvents in industrial applications, covering esters, alcohols, ketones, common halogenated hydrocarbons, benzene derivatives and other core materials. This type of solvent has no clear human carcinogenicity, but there is significant chronic accumulation toxicity and specific target organ damage. There is no clear human carcinogenicity, but there is significant chronic accumulation toxicity and specific target organ damage : Toluene and xylene are mainly caused by central nervous system damage; methanol damages the optic nerve; dichloromethane and tetrachloroethylene have potential hepatorenal toxicity; acetate esters and ketones are mainly at risk of mucosal stimulation and acute anesthesia.: Toluene and xylene are mainly caused by central nervous system damage; methanol damages the optic nerve; dichloromethane and tetrachloroethylene have potential hepatorenal toxicity; acetate esters and ketones are mainly at risk of mucosal stimulation and acute anesthesia.

Its core control difficulty lies in "risk concealment". Most of the second-class solvents have mild odor and low probability of acute poisoning. Enterprises are prone to ignore protection. However, long-term low-concentration exposure can cause occupational problems such as neurasthenia, abnormal liver and kidney metabolism, and chronic skin damage. It is the main cause of the current high incidence of occupational diseases. It is necessary to strictly implement normal control measures such as ventilation, personal protection, and annual occupational physical examination. The core control difficulty lies in "risk concealment". Most of the second-class solvents have mild odor and low probability of acute poisoning. Enterprises are prone to neglect protection. However, long-term low-concentration exposure can cause occupational problems such as neurasthenia, abnormal liver and kidney metabolism, and chronic skin damage. It is the main cause of the current high incidence of occupational diseases. It is necessary to strictly implement normal control measures such as ventilation, personal protection, and annual occupational physical examination.

3. The third category of organic solvents: low-risk petroleum-based control category 3. The third category of organic solvents: low-risk petroleum-based control category

The third type of solvents are all light components of petroleum fractionation, and the third type of solvents are all light components of petroleum fractionation. They belong to the solvent system of low toxicity and low accumulation, only acute risk low toxicity and low accumulation, and only acute risk , including gasoline, petroleum ether, turpentine, etc. These solvents have no chronic carcinogenic and teratogenic risks, and the human body can rapidly metabolize without accumulation. The core hazards are central nervous anesthesia at high concentrations, skin degreasing stimulation, and extreme flammable and explosive risks. of solvent system, including gasoline, petroleum ether, turpentine, etc. This type of solvent has no chronic carcinogenic and teratogenic risks, and the human body can rapidly metabolize without accumulation. The core hazards are concentrated in central nervous anesthesia at high concentrations, skin degreasing stimulation, and extreme flammable and explosive risks.

Therefore, the control core of the three types of solvents focuses on fire safety, explosion-proof and anti-static, and the occupational health control requirements are relatively loose. It is a relatively safe solvent category in industrial cleaning, dilution and extraction scenarios. Therefore, the control core of the three types of solvents focuses on fire safety, explosion-proof and anti-static, and the occupational health control requirements are relatively loose. It is a relatively safe solvent category in industrial cleaning, dilution and extraction scenarios.

5. Industry-specific knowledge: Industrial application and iterative trend of solvent classification 5. Industry-specific knowledge: Industrial application and iterative trend of solvent classification

From the perspective of process optimization and safety upgrade, the classification system of organic solvents directly determines the logic of industrial substitution: the core direction of the current green upgrade in the chemical industry is from the perspective of process optimization and safety upgrade. The classification system of organic solvents directly determines the logic of industrial substitution: the core direction of the current green upgrade in the chemical industry is the complete elimination of first-class solvents, the precise control of second-class solvents, and the standardized use of three-class solvents. At the same time, ketones and high-carbon ester low-toxic solvents replace traditional high-toxic benzene and halogenated hydrocarbon solvents.