Peroxyacetic acid is a colorless and transparent liquid with pungent sour taste. Volatile, soluble in water and organic solvents. The melting point is 0. 1℃, the boiling point is 1 10℃ and the specific gravity is 1.226. Strong corrosiveness and bleaching. Unstable properties, easy to decompose when exposed to heat or organic matter, heavy metal ions, strong alkali, etc. A high concentration solution with a content of more than 45%(g/mL) may explode after violent collision or heating (flash point 40.5℃). However, the concentration of peracetic acid used for disinfection in the market is mostly around 20%, which is generally not dangerous.
Peroxyacetic acid is a strong oxidant, and its sterilization mechanism mainly depends on oxidation. However, it is speculated that peracetic acid has such a powerful and extensive bactericidal effect, and besides its strong oxidation, the synergistic effect of hydrogen peroxide and acetic acid also plays a certain role.
Synthesis technology of 1
In the traditional production process of peracetic acid, acetic acid with a concentration of 50% or 70% and hydrogen peroxide are mixed according to the molar ratio of 1: 0.44, and 5% by weight sulfuric acid is added as a catalyst to react at room temperature for 20 h. The obtained product contains about 265438 0% peracetic acid, 5% sulfuric acid, 47% acetic acid, 6% hydrogen peroxide and 265433 water. The product content is low, the utilization rate of acetic acid is low, and 50% and 70% high-concentration hydrogen peroxide is easy to explode, which has great hidden dangers in production safety. Therefore, people have developed the production technology of peracetic acid to improve product quality and reduce potential safety hazards.
At present, there are many synthetic methods of peracetic acid, including acetic acid (or acetic anhydride), acetaldehyde oxidation and acetyl activator method.
1. 1 acetic anhydride) method
Acetic acid (or acetic anhydride) method is to react acetic acid with hydrogen peroxide to produce peracetic acid under the catalysis of acid. The chemical reaction equation is as follows:
CH3COOH+H2O2=CH3COOOH+H2O
If acetic anhydride is used as acetylating agent instead of acetic acid, its chemical reaction with hydrogen peroxide is as follows:
(CH3CO)2O+2 H2O2=2 CH3COOOH+H2O
However, a lot of heat will be generated in this reaction process, and diacyl peroxide may also be produced, which may lead to explosion. Therefore, from the perspective of safety, acetic acid is still the best method to synthesize peracetic acid from hydrogen peroxide.
Seppo Pohjanvesi and others studied the continuous production process of acetic acid and hydrogen peroxide. It was found that the optimum reaction solvent ratio was 10% ~ 20%, acetic acid 15% ~ 30%, peracetic acid/5% ~ 20%, sulfuric acid 10% ~ 20% and water/30% ~ 50%.
Lin Huiqiong and others investigated the effects of hydrogen peroxide concentration, glacial acetic acid dosage and different stabilizer content on product stability in the production of peracetic acid. The results show that when the content of hydrogen peroxide is 280, 350 and 500 g/L, it reacts with twice the amount of glacial acetic acid, and the highest concentration of peracetic acid is 157.5, 192.0 and 292.0 g/L, respectively. The higher the concentration of peracetic acid, the worse the storage stability, and 1g was added to the product.
In order to study the optimum proportion, preparation and storage conditions of peracetic acid products, Wang Chuanhu and others used different proportion screening and observation of influencing factors to carry out experimental observation in the laboratory. The results showed that when the mass ratio of acetic acid to hydrogen peroxide was 2: 1, the dosage of sulfuric acid was 30 ~ 50g/L, the reaction temperature was 25℃ and the reaction time was 24 h, the content of peracetic acid was the highest. According to the observation of influencing factors, increasing the temperature can accelerate the decomposition rate of peracetic acid, and the best dilution water of peracetic acid is double distilled water. Adding 2 000 mg/L 8- hydroxyquinoline to peracetic acid products can obviously improve the stability of peracetic acid.
Zheng et al. disclosed a patent on the production method of peracetic acid. Firstly, acetic acid and 27% hydrogen peroxide are mixed according to the molar ratio of 1: 1, and a catalyst accounting for 2%-5% of the weight of the reactants is added for reaction, wherein the catalyst is benzene sulfonic acid with a concentration of 3% or sulfuric acid with a concentration of 98%, the reaction temperature is 25-35℃, and the reaction time is1-3 h. Then, The content of peracetic acid in the product produced by this method is high, generally above 50%, and it can be prepared into different concentrations by adding water. When used in various industries, the utilization rate of crude acetic acid is high and the production safety is good. The produced product does not contain sulfuric acid, and the content of peracetic acid can be adjusted by increasing or decreasing the tower efficiency.
Takeo Ohsakadeng and others have recently developed a method for producing peracetic acid by electrolysis. In this process, acetic acid (or acetate) and oxygen-containing gas are used as raw materials and solid acid is used as catalyst to synthesize peracetic acid in an electrolytic cell. The process has low cost and broad application prospects.
1.2 acetaldehyde oxidation method
Acetic acid can be obtained by oxidation of acetaldehyde. Peracetic acid can be obtained by changing the oxidation conditions of acetaldehyde and lowering the reaction temperature. The chemical reaction equation is as follows:
CH3CHO - CH3COOOH
This reaction is more complicated. In order to obtain higher conversion and yield of peracetic acid, it is necessary to add appropriate catalysts. There are three production processes for the oxidation of acetaldehyde to peracetic acid: gas phase method, acetaldehyde monoperoxyacetic acid vinegar method and liquid phase method.
1.2. 1 gas phase method and acetaldehyde monoperoxyacetic acid vinegar method
The gas phase method is to mix acetaldehyde with oxygen and react at 150 ~ 160℃. This method uses oxygen as a catalyst to improve the yield of peracetic acid. The tail gas can be recycled, which reduces the production cost. However, the danger of gas explosion is great, and the utilization rate of equipment is low because of a large amount of acetaldehyde circulation.
Acetaldehyde monoperoxyacetic acid vinegar method is rarely used because of unreasonable energy utilization and high equipment investment and operation cost.
1.2.2 liquid phase method
Wang Qinghai and others studied this process in detail, and the process of synthesizing peracetic acid by liquid-phase oxidation of acetaldehyde was investigated with ethyl acetate as solvent and acetic acid drill as catalyst. The effects of stirr60ming speed, catalyst concentration, initial acetaldehyde concentration, oxygen pressure and temperature on the reaction were studied, and the optimum technological conditions were obtained: the ion concentration in drilling hole was 2× 10-5, the initial acetaldehyde concentration was1.75 ~ 2.20 mol/L, the reaction temperature was 20 ~ 25℃, the oxygen pressure was 0.75MPa, and the reaction temperature was 0.75 MPa.
1.3 acetyl activator method
Generally speaking, peracetic acid can be produced by the reaction of tetraacetylethylenediamine and sodium percarbonate in aqueous solution. In addition, tetraacetyl ethylenediamine and sodium percarbonate are solid, which is convenient for storage and transportation. The chemical reaction equation is as follows:
3(CH3CO)2 nch 2ch2 n(coch 3)2+2 na2co 3·3h2o 2 = 2 na2co 3+3 ch 3 conh ch 2ch2 NH coch 3+6 ch 3c oooh
In addition, acetylsalicylic acid can react with sodium percarbonate and also generate peracetic acid. The chemical reaction equation is as follows:
3 cooh 6 H4 cooch 3+2 Na2CO。 3 H2O = 3 hoc 6 H4 cooh+2 na2co 3+3 ch 3c oooh
Duan Qingnan applied for a patent for peracetic acid solid preparation and its manufacturing method. It consists of coated tetraacetyl ethylenediamine or tetraacetyl glycoluril and coated sodium perborate or coated sodium percarbonate; The liquid dosage form of peracetic acid is changed into powder solid dosage form after solid drug coating, which has the characteristics of stable product, no decomposition at room temperature, convenient transportation, no odor, no corrosion and commercialization in the whole preparation and use process. However, there are some disadvantages, such as poor solubility, slow reaction to prepare peracetic acid, and the decrease of effective components in the solution due to volatilization.
Zhang et al. improved this process by adding surfactant, which reduced the surface tension of acetylation activator in water, accelerated the preparation speed of peracetic acid, and was beneficial to retain the effective components of peracetic acid in the preparation solution.
You should use 2
2. Application of1in disinfection
From the mid-1970s to the 1980s, peracetic acid was widely used. In the 1990s, due to the increasing use of glutaraldehyde, iodophor, chlorine dioxide and various chlorine-containing disinfectants, the use of peracetic acid decreased. Peroxyacetic acid is mainly used for disinfection and sterilization of corrosion-resistant articles, environment and skin. If compounded with corrosion inhibitor, it can also be used for sterilization of medical devices. Like most chemical disinfectants, the disinfection effect of peracetic acid is affected by concentration, action time, temperature, organic matter, relative humidity and chemical substances. The commonly used disinfection methods of peracetic acid mainly include soaking, wiping, spraying and fumigation.
2.2 Application in medical treatment
Mainly used for treating dermatoses infected by fungi or viruses. Low-concentration peracetic acid is not only a keratolytic agent, but also a broad-spectrum disinfectant, which can not only make keratinized keratinocytes loose and free, promote their shedding, but also have a powerful killing effect on various dermatophytes. Can promote wound healing and treat plantar warts and common warts. In addition, peracetic acid can also be used to treat oral ulcers and soft tissue infections.
2.3 Other applications
Peroxyacetic acid is also used to prevent ammonia poisoning in broilers, as a medicine to prevent chicken diseases, pulp bleaching, improving germination rate in soilless culture, chemical oxidant in drug synthesis, intermediate in chemical synthesis, and scale remover in oxygen humidification bottles.
Dong Wudai and others applied peracetic acid to soilless culture. Treating plants with 0.0 1%-0.4% (by weight) peracetic acid aqueous solution can greatly reduce the rejection rate of soilless culture pollution, thus greatly reducing the production cost.
Peroxyacetic acid can be used to synthesize propylene oxide, which was first industrialized by Daicel Company of Japan on 1969.