Chinese name: carbamate mbth: Carbmate properties: important drugs and pesticides general formula: RNHCOOR's toxicity: toxic application: chemical pesticides, sedatives and other substances, material application, organic synthesis, medicine, pesticides, clothing moth-proofing, low-shrinkage cement, textile finishing agent, surfactant, resin modification, precautions, symptoms and signs of poisoning, diagnosis and inspection of poisoning, and treatment of poisoning. Material composition: a class of compounds with the general formula RNHCOOR', in which R is hydrogen, aliphatic hydrocarbon group or aromatic hydrocarbon group, and R' is aliphatic hydrocarbon group or traditionally, carbamates with substituents on amino groups are generally called N- carbamates, such as N- benzyl ethyl carbamate C6H5h2NHCO2H5; There is no substituent on the amino group called o-carbamate, such as benzyl o-carbamate. Through the application of carbamate compounds, carbamate chemically reactive substances can be widely used, and carbamate compounds can be used as pesticides, drugs, intermediates for modification of synthetic resins and organic synthesis. Organic synthesis of isocyanate isocyanate is synthesized by thermal decomposition of carbamate, which has no environmental pollution, low requirements for equipment, great flexibility in plant construction and good application prospects. In the presence of phosphorus pentoxide dehydrating agent, acetanilide reacts with carbamate to produce quinazolinone with low yield. N- substituted 2,5-dimethylpyrrole was obtained by the reaction of carbamate compounds with acetone, which has excellent ultraviolet resistance and good compatibility with rubber, plastics and various resins. Synthesis of non-toxic polyurethane carbamate and transesterification of polyol gave polyol carbamate compound, whose structure was similar to polyamide. Polyurethane is crosslinked with aldehydes of polyols to produce polymers with polyurethane structure, which are used as coatings, adhesives and so on. Polyurethane synthesized by the above method does not contain residual toxic isocyanate groups, which is called nontoxic polyurethane. N- substituted carbamate compounds can be synthesized by the addition reaction of methyl carbamate with olefins. In the presence of mercury nitrate, styrene and carbamate have an addition reaction to obtain N- phenylethyl carbamate with a yield of 99%. Tert-butyl carbamate was synthesized from carbamate and isobutylene under the catalysis of acidic ion exchange resin, and the yield was 93%. Synthesis of Diphenylmethyl Phosphonate Benzyl carbamate, aldehyde and triphenyl phosphate reacted, and the product reacted with hydrogen bromide to obtain Dipeptide containing phosphorus. These compounds have biological activities such as sterilization, weeding and regulating plant growth. N- substituted carbamates or alkylene dicarbamates are obtained by reacting carbamates with most aldehydes and some highly active ketones. Acetals or ketals are more likely to react with carbamates. When carbamate reacts with aldehyde, the reaction degree can be controlled by adjusting the pH of the reaction medium. Generally, under alkaline conditions, aldehydes react with one molecule of carbamate, and under acidic conditions, they react with two molecules of carbamate to form alkylidene groups. Synthetic melamine derivative hexamethoxymethyl melamine is the curing agent of hydroxyl-containing resins (such as epoxy resin and hydroxyethyl acrylate), but formaldehyde will escape when the resin is cured, which will pollute the environment. Using carbamate derivatives of melamine as curing agent can avoid environmental pollution and improve the ability of resin to resist scale remover and salt corrosion. Peter et al. reacted carbamate with hexamethoxymethyl melamine under acidic conditions to produce methyl melamine based on hexacarbamate. The traditional synthesis methods of dialkyl carbonate include alkylation of alkali metal carbonate with chloroalkane, alcoholysis of phosgene, carboxylation of carbon monoxide and alcohol in the presence of palladium salt, etc. Alcoholysis of carbamate is also one of the routes to synthesize dialkyl carbonate, but the previous technology requires high pressure and high temperature reaction, with low yield (40%) and long reaction time. Mizukami et al. carried out the alcoholysis of carbamate in the presence of a high-boiling organic compound, which obviously promoted the reaction. The inventors claim that this promotion is far greater than the effect of increasing the reaction temperature, so the reaction under mild conditions can produce higher yield of dialkyl carbonate. Poly (vinylamine) poly (vinylamine) is one of the few cationic resins, which is a new type of resin developed in recent years. Polyacrylamide reacts with polyacrylic acid to form polyelectrolyte complexes, which are widely used in the fields of drug sustained release, environmental protection, new membrane materials, mechanochemical devices, template polymerization, protein separation and molecular self-assembly. Firstly, carbamate reacts with acetaldehyde to produce 1, 1- bis (alkoxycarboxyamino) ethane, and then pyrolyzes at high temperature to produce N- vinyl carbamate. In the presence of initiator, N- vinyl carbamate undergoes free radical polymerization to produce polyvinyl carbamate, and polyvinyl amine is obtained through acid hydrolysis and alkali neutralization. One-step synthesis of N- vinyl carbamate by pyrolysis is the key to the synthesis technology of polyvinyl amine. Waller proposed using activated carbon as a catalyst for pyrolysis, which had a good catalytic effect. The yield of N- vinyl carbamate was about 60%. For a long time, medical carbamate compounds have been used as sedatives in medicine. These compounds have mild hypnotic effect and are suitable for children and heart patients. Alprna (ethyl carbamate) is one of the earliest varieties used as a sedative. In recent years, phenyl substituted ethyl or propylene glycol dicarbamate has been used as anti-inflammatory, muscle relaxant, analgesic and antiepileptic drugs, and achieved good results. 2- amino -3- phenylpropyl carbamate has the function of regulating the central nervous system. Some complex carbamate compounds have certain anti-cancer effects. Pesticide carbamate compounds are used as insecticides, acaricides, herbicides [imazalil, methyl n-(3,4-dichlorophenyl) carbamate] and fungicides, and have formed a large category of pesticides with many varieties, good efficacy and low toxicity. Carbamate pesticides are the main cause of acute pesticide poisoning, and are also the key detection varieties of pesticide residues in vegetables at present. Enzyme inhibition method is a detection method based on its toxicological mechanism to insects. The toxicological mechanism of organophosphorus and carbamate insecticides is the same, both of which inhibit the activities of acetylcholinesterase (Ache) and carboxylesterase, leading to the accumulation of acetylcholine (Ach) and carboxylate, affecting the normal nerve conduction of insects and leading to death. This kind of pesticides can be divided into five categories: ① naphthalene carbamate, such as carbaryl (N- methylamino -4- naphthyl ester); 2 phenyl carbamate, such as yechan powder; ③ Oxime carbamate, such as aldicarb; (4) heterocyclic methyl carbamate, such as carbofuran; ⑤ dimethyl heterocyclic carbamate, such as isosorbide. Except for a few varieties such as carbofuran, which are highly toxic, most of them belong to medium and low toxicity. In the past, naphthalene, camphor and p-dichlorobenzene were used as mothproof agents for clothes, but their insecticidal activities were not satisfactory, especially for preventing larvae from invading clothes. P-dichlorobenzene is easy to scar on clothes, which will do harm to some plastic packaging materials used on clothes. Using carbamate compounds as moth-proofing agent can avoid the above shortcomings, and it has the characteristics of tasteless, moderate volatility, low toxicity and good moth-proofing effect, and has a good application prospect. The main disadvantage of low shrinkage cement is that it is easy to shrink and produce cracks during curing. In winter, water enters the cracks, and after freezing and expansion, it exerts pressure on the structure, gradually causing more serious damage. However, by adding some chemicals, the shrinkage of cement during solidification can be reduced and cracks can be avoided. In Japanese patent, polyethylene glycol or adduct of ethylene oxide and alkyl phenol is used as an anti-shrinkage agent, but its dosage is large and its cost is high. Yasuhide et al. used C 4 ~ C 6 alcohol as anti-shrinkage agent of cement, but the effect was poor in drying and curing, and the alcohol was volatile and difficult to control in operation. Abdirazig et al. used n-butyl carbamate to make cement have good shrinkage resistance during dry curing and wet curing. This substance is stable, non-volatile, low in dosage and low in cost. Fabric finishing agent carbamate is condensed with formaldehyde instead of urea, and then etherified with ethylene glycol to obtain fabric finishing agent for fiber treatment. Compared with previous products, it has better resistance to acid and alkali hydrolysis, and the fabric after treatment and heat setting is smooth and wrinkle-resistant. Surfactant Jean-Marc and others designed and synthesized a carbamate, which can be used as a surfactant. These compounds can be used in cosmetics, especially hair treatment agents, which can give hair a good appearance and luster, increase the affinity of water in the stratum corneum of hair, have a good water retention effect, and have less damage to skin than other surfactants. The representative compound is N-2- ethylhexoxycarbonyl -N- methyl -D- glucosamine, the surface tension dimension is 26.5dyn/cm, and the critical micelle concentration is 0.011mol/L. Resin modified n-hexyl carbamate can make phenolic resin elastic, and its elasticity depends on the amount of carbamate and the resin. This modified phenolic resin has low water absorption, good moisture resistance and excellent adhesion to inorganic materials such as metal, glass and ceramics, and is an ideal material for exporting elastic sealant. It can also produce plastic polyurethane modified phenolic coatings. A transparent urethane modified acrylate coating with good transparency and acid rain resistance can be obtained by modifying polyacrylate with n-butyl carbamate or hydroxyethyl carbamate. Precautions Symptoms and Signs of Poisoning Carbamate pesticides, like organophosphorus pesticides, also inhibit cholinesterase in the human body, thus affecting the transmission of nerve impulses in the human body. However, carbamate pesticide poisoning occurs quickly and recovers much faster. When these pesticides are sprayed without proper protective measures, they will feel uncomfortable and stop working after a while. Because contact is terminated immediately, patients will begin to feel better, unless they continue to absorb pesticides through contaminated clothes or skin. Carbamate pesticides began to show specific poisoning symptoms after 3 hours of continuous work. The initial symptoms of poisoning are that the poisoned person feels unwell, and may have vomiting, nausea, headache and dizziness, fatigue and chest tightness. After that, the patient began to sweat a lot and drool (drooling), blurred vision, spontaneous muscle contraction, convulsions, tachycardia or bradycardia, and a few people may have spasms and enter a coma. Generally, patients will fully recover within 24 hours (except those poisoned by extremely high dose), and there will be no sequelae and disability. Poisoning diagnosis and examination 1. Diagnostic principle: According to the occupational history of short-term exposure to a large number of carbamate insecticides, the corresponding clinical manifestations appear quickly, combined with the timely determination results of cholinesterase activity in whole blood, referring to the on-site labor hygiene investigation data, comprehensive analysis, and excluding other reasons, the diagnosis can be made. 2 Diagnostic and grading criteria 2. 1 Mild muscarinic and central nervous system symptoms, such as dizziness, headache, fatigue, blurred vision, nausea, vomiting, salivation, hyperhidrosis and miosis, appear after short-term close contact with carbamate. It may be accompanied by nicotine-like symptoms such as muscle tremor, and generally returns to normal within 24 hours. The whole blood cholinesterase activity is often lower than 70%. 2.2 Severe poisoning can be diagnosed as severe poisoning. In addition to the aggravation of the above symptoms, there are any of the following: a. Pulmonary edema; B. coma or brain edema; The whole blood cholinesterase activity is generally below 30%. Treatment principle of poisoning treatment plan: 1 treatment principle 1. 1 Leave the poisoning scene quickly, take off the contaminated clothes, and thoroughly wash the contaminated skin, hair and nails with soap and warm water. 1.2 Special detoxification drugs: a) Patients with mild poisoning do not need special detoxification drugs, and atropine can be given orally or intramuscularly if necessary, but atropine is not necessary; B) Patients with severe poisoning should apply atropine according to their condition and get atropine as soon as possible; C) Simple carbamate pesticide poisoning does not require oxime regenerant. 1.3 The principle of symptomatic treatment is the same as that of internal medicine. Other treatments can still engage in the original work after the poisoning is cured.