Methanol is moderately toxic and can enter the body through respiratory tract, skin and digestive tract. Occupational poisoning is mainly respiratory tract. As a nerve agent, methanol has obvious anesthetic effect, especially on optic nerve and retina. Repeated exposure to moderate concentrations of methanol can lead to temporary or permanent visual impairment and blindness. The toxic range of methanol is narrow, so acute poisoning has serious consequences and often leads to death. Its acute occupational poisoning has a certain incubation period, and its poisoning performance is similar to that of drunkenness. According to the results of animal experiments, it is dangerous for people to be exposed to 39.3-65.5 g/m3 of methanol vapor for 30-60 minutes. Different from other alcohols, methanol is oxidized slowly in the body and has obvious accumulation effect. Without protection, working in an environment that exceeds the national hygiene standards will gradually lead to chronic poisoning. Domestic data show that the upper limit of environmental concentration is 260mg/M3, and industrial exposure is harmless. In addition, long-term skin contact with liquid methanol can lead to local warm feeling, mild congestion or degreasing, itching, and even dermatitis and eczema. Although methanol is a nerve agent, it has been reported that methanol poisoning can cause multiple organ damage. Workers in a material factory in Jilin mistakenly heated methanol into toluene in production. When the temperature reaches 450C, a large amount of methanol escapes and the indoor ventilation is poor. After about 20 minutes, dizziness, headache, nausea, vomiting, tachycardia and a small amount of water in the right renal pelvis appeared. Three people were poisoned in the accident. In addition, there are reports of eye injuries caused by occupational acute methanol poisoning in Heilongjiang. The literature also reports that there are multiple peripheral neuritis besides heart, liver, lung and kidney damage. There are also cases of eye damage and blindness caused by repeated scrubbing of skin with methanol abroad. Many experts believe that the chronic effect of occupational exposure to methanol is visual conduction disorder, which is a demyelinating lesion of the nervous system. With the extension of exposure time, the damage is aggravated and positively correlated.
toluene
Chemical document 1. Physical and chemical constants of matter:
National standard number 32052
Si Nuo. 108-88-3
Chinese name toluene
English name toluene; ; toluene
Another name for toluene.
Molecular formula C7H8；; The appearance and properties of CH3C6H5 are colorless and transparent liquid, with an aromatic smell similar to benzene.
Molecular weight 92. 14 vapor pressure 4.89kPa/30℃ flash point: 4℃
Melting point -94.4℃ Boiling point: 1 10.6℃ Insoluble in water, soluble in most organic solvents such as benzene, alcohol and ether.
Density Relative density (water =1) 0.87; Relative density (air = 1)3. 14 is stable.
Danger sign 7 (flammable liquid) is mainly used for blending gasoline components and as the main raw material for producing toluene derivatives, explosives, dye intermediates and drugs.
2. Impact on the environment:
I. Health hazards
Invasion route: inhalation, ingestion and percutaneous absorption.
Health hazard: it is irritating to skin and mucous membrane and has anesthetic effect on central nervous system.
Acute poisoning: Inhalation of high concentration of this product in a short time can cause obvious irritation to eyes and upper respiratory tract, congestion of conjunctiva and pharynx, dizziness, headache, nausea, vomiting, chest tightness, weakness of limbs, stumbling gait and confusion. In severe cases, restlessness, convulsions and coma may occur.
Chronic poisoning: neurasthenia syndrome, hepatomegaly and abnormal menstruation of female workers may occur after long-term contact. Dry skin, chapped skin, dermatitis.
Second, toxicological data and environmental behavior.
Toxicity: low toxicity.
Acute toxicity: LD505000mg/kg (taken orally by rats); LC50 12 124mg/kg (rabbit skin); Inhalation of 7 1.4g/m3 will cause death in a short time; People inhale 3g/m3×1~ 8h, resulting in acute poisoning; Inhalation of 0.2 ~ 0.3g/m3× 8h may cause poisoning symptoms.
Stimulation: 300ppm passes through human eyes, causing irritation. Percutaneous rabbit: 500mg, moderately stimulated.
Subacute and chronic toxicity: Rats and guinea pigs inhaled 390 mg/m3 for 90 ~ 127 days and 8 hours/day, which caused changes in hematopoietic system and parenchymal organs.
Mutagenicity: mouse micronucleus test: 200mg/kg. Cytogenetic analysis: rats inhaled 5400? 0? 8g/m3, 16 weeks (intermittent).
Reproductive toxicity: The lowest toxic concentration (TCL 0) of rats in 24 hours (taking medicine on 1 ~ 18 days of pregnancy) is 1.5g/m3, which causes embryo toxicity and abnormal muscle development. The lowest toxicity concentration (TCL 0) of mice for 24 hours (6 ~ 13 days) was 500 mg/m3, which caused embryo toxicity.
Metabolic degradation: 80% of toluene absorbed in the body is oxidized to benzyl alcohol in the presence of NADP (transferase II), then to benzaldehyde in the presence of NAD (transferase I), and then to benzoic acid. Then it combines with glycine in the presence of transferase A and adenosine triphosphate to form hippuric acid. Therefore, 16%-20% of toluene absorbed by human body is exhaled from respiratory tract in the original form, and 80% is excreted through kidney in the form of hippuric acid. Therefore, after the human body was exposed to toluene, hippuric acid in urine rose rapidly after 2 hours, and then stopped rising slowly, and returned to normal after 16-24 hours. A small part of benzoic acid combines with glucuronic acid to form non-toxic. The amount of toluene metabolized into o-cresol is less than 65438 0%. In the environment, toluene reacts with air in the presence of strong oxidant or catalyst, and is oxidized into benzoic acid or directly decomposed into carbon dioxide and water.