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Industrial organic material antioxidants
2018-1-13 11:27:51
Industrial organic material antioxidants
Most industrial organic materials, whether natural or synthetic are prone to oxidation reaction, such as plastic, fiber, rubber, adhesives, lubricants, and food and feed and so on all has the nature of reaction with oxygen.
And when you react with oxygen, it loses its beneficial properties. Fuel oil oxidation produce precipitation, blocking machine valve or tubing, the engine can work normally, acid oxidation products and can accelerate the corrosion of the machine and and make fuel oil ignition in advance. Oxidation of lubricants can increase viscosity and produce gels and impurities, which also speed up the corrosion and wear of the equipment. Oxidation of food and feed will spoil and spoil the original flavor. The lipoproteins formed by oxidation in mammals are the main culprits of arteriosclerosis and other diseases.
In order to try to contain, prevent or delay oxidation phenomenon occurs, find out an effective, convenient and no need to change the existing production technology, the method of the antioxidants in industrial organic materials.
The antioxidant agents of industrial organic materials can be divided into three types, namely main antioxidant, auxiliary antioxidant and carbon free radical capture agent.
(1) main antioxidant. Usually the main antioxidant can capture the oxygen-free radicals produced in the aging of the polymer. OH, RO? , ROO?) And carbon free radicals (but poor effect), thereby terminating or slowing down the generation of the compounds that are ageing.
(2) auxiliary antioxidants. It is a kind of ability to hot oxygen aging of polymer in the chain reaction after oxide decomposition, lose the generation of active compounds rather than reactive free radicals, and thus stop or slow down the occurrence of the hot oxygen aging. Because it has a synergistic effect with the main antioxidant, it only works best when used with antioxidants, so it is known as an auxiliary antioxidant.
(3) carbon capture free radicals agent it can will be terminated polymer hot oxygen aging of chain reaction in the bud, reason has very good thermal oxygen aging effect, especially in the traditional free radical catching agent with better results.
The addition of main antioxidant (free radical capture agent) can be used to cut off the growth of the chain and prevent the degradation of more polymer molecules. The addition of auxiliary antioxidant can eliminate the root causes of free radicals and reduce the generation of free radicals, thus improving the thermal oxygen stability of the polymer.
Triphenyl phosphite (antioxidant, stabilizer TPPi) production process
1. Phosphorus oxychloride as the direct method (also called thermal method) phenol with pyridine and anhydrous benzene as solvent, in no more than 10 ℃ temperature, slowly add oxygen phosphorus chloride, then under reflux temperature, the reaction of 3 ~ 4 h. After cooling to room temperature, the reactants are washed by water to recycle pyridine. After centrifugal dehydration, the reagents are dehydrated with dried sodium sulfate, which is filtered to remove sodium sulfate. The first atmospheric distillation recovery of benzene, vacuum distillation, collected 243 ~ 245 ℃ (1.47 kPa) fraction, by cooling, crystallization, crushing is the finished product.
2. After phenol melting, stirring under add phosphorus trichloride under 25 ℃, Triphenyl phosphite is generated; Then heat up to 70 ℃ ventilation with chlorine gas, generated two chlorinated triphenyl phosphate; Again at 50 ℃ water hydrolysis, triphenyl phosphate. The hydrolysate with 5% soda solution for neutralization, water washing, the evaporation and vacuum distillation, collected 243 ~ 245 ℃ (1.47 kPa) fractions, cooling, crystallization, crushing, packaging is the finished product.
Triphenyl phosphite (TPPi antioxidants, stabilizer) is mainly used in PVC, polyethylene, polypropylene, polystyrene, polyester, abs resin, epoxy resin, synthetic rubber antioxidant stabilizer, used in polyvinyl chloride (PVC) products as a chelating agent.
The effect of molecular structure on the antioxidant of industrial organic materials. Ortho group R1, R2 (1) if the influence of R1, R2 volume is larger, the benzene ring and hydroxyl not in the same plane, hinders oxygen P on the electronics and electronic conjugate on the benzene ring, the replace phenol molecules lost due to the effect the stability of the resonance effect, the result is to make hydroxyl H easier to escape. (2) when R1, R2 is too large, the free radicals are not easily accessible to the hydroxyl group due to the obstruction of space, which makes it difficult to capture the effect of free radicals. So R1, R2 shouldn't be too big.
In recent years, studies have shown that R1, R2 for t - Bu, its antioxidant efficiency highest, reason is the large volume of t - Bu stereoscopic protection of phenolic hydroxyl, so most of the performance is hindered phenol antioxidant 2, 6 for tert-butyl replace.
However, recent studies have found that phenol hydroxyl group has a better antioxidant effect with a methyl and a tert-butyl semi - retarded phenol structure. On the one hand, the space resistance of tert-butyl is sufficient to protect the phenolic hydroxyl group. On the other hand, the anti-oxygen reaction rate of the methyl groups on the adjacent side is faster, so the anti-oxygen activity is increased. Moreover, it has an advantage in the combination of NOx stain and sulfur-assisted antioxidant synergism.
The difficulty of having an H out of a position group in R3 is very much affected by R3.
(1) when R3 is an electron absorption group, such as NO2 and COOH, it is easy to get rid of the hydroxyl group without replacing the base.
(2) when R3 is for electronic groups, such as Me, t-bu, it is easy to get rid of the hydroxyl group without replacing the base.
(3) when R3 is a long chain alkyl, it is beneficial to improve the compatibility, thus improving the efficiency of antioxidant.
Molecular structure and compatibility when Rl, R2, R3 are alkyl groups or groups similar to polymer structures, they can increase the compatibility of antioxidants with polymers.
The effect of molecular weight on antioxidant. Polymer materials in the air in 220 ￣ 350 ℃ hot working, must use antioxidants to prevent oxidation in the process of machining.
Therefore, the thermal stability of the antioxidants is very important. In recent years, the research shows that improving the molecular weight is an important means to improve the thermal stability and efficiency of antioxidant. But there is an ideal molecular weight. An antioxidant with ideal molecular weight has the highest efficiency.
After years of research shows that the gm antioxidant its ideal molecular weight between 500 ￣ 1000, as for polymer antioxidants its molecular weight between 1000 ￣ 3000.
Copyright: Zhang Jia Gang YaRui Chemical co.,Ltd
http://www.yaruichem.com
Most industrial organic materials, whether natural or synthetic are prone to oxidation reaction, such as plastic, fiber, rubber, adhesives, lubricants, and food and feed and so on all has the nature of reaction with oxygen.
And when you react with oxygen, it loses its beneficial properties. Fuel oil oxidation produce precipitation, blocking machine valve or tubing, the engine can work normally, acid oxidation products and can accelerate the corrosion of the machine and and make fuel oil ignition in advance. Oxidation of lubricants can increase viscosity and produce gels and impurities, which also speed up the corrosion and wear of the equipment. Oxidation of food and feed will spoil and spoil the original flavor. The lipoproteins formed by oxidation in mammals are the main culprits of arteriosclerosis and other diseases.
In order to try to contain, prevent or delay oxidation phenomenon occurs, find out an effective, convenient and no need to change the existing production technology, the method of the antioxidants in industrial organic materials.
The antioxidant agents of industrial organic materials can be divided into three types, namely main antioxidant, auxiliary antioxidant and carbon free radical capture agent.
(1) main antioxidant. Usually the main antioxidant can capture the oxygen-free radicals produced in the aging of the polymer. OH, RO? , ROO?) And carbon free radicals (but poor effect), thereby terminating or slowing down the generation of the compounds that are ageing.
(2) auxiliary antioxidants. It is a kind of ability to hot oxygen aging of polymer in the chain reaction after oxide decomposition, lose the generation of active compounds rather than reactive free radicals, and thus stop or slow down the occurrence of the hot oxygen aging. Because it has a synergistic effect with the main antioxidant, it only works best when used with antioxidants, so it is known as an auxiliary antioxidant.
(3) carbon capture free radicals agent it can will be terminated polymer hot oxygen aging of chain reaction in the bud, reason has very good thermal oxygen aging effect, especially in the traditional free radical catching agent with better results.
The addition of main antioxidant (free radical capture agent) can be used to cut off the growth of the chain and prevent the degradation of more polymer molecules. The addition of auxiliary antioxidant can eliminate the root causes of free radicals and reduce the generation of free radicals, thus improving the thermal oxygen stability of the polymer.
Triphenyl phosphite (antioxidant, stabilizer TPPi) production process
1. Phosphorus oxychloride as the direct method (also called thermal method) phenol with pyridine and anhydrous benzene as solvent, in no more than 10 ℃ temperature, slowly add oxygen phosphorus chloride, then under reflux temperature, the reaction of 3 ~ 4 h. After cooling to room temperature, the reactants are washed by water to recycle pyridine. After centrifugal dehydration, the reagents are dehydrated with dried sodium sulfate, which is filtered to remove sodium sulfate. The first atmospheric distillation recovery of benzene, vacuum distillation, collected 243 ~ 245 ℃ (1.47 kPa) fraction, by cooling, crystallization, crushing is the finished product.
2. After phenol melting, stirring under add phosphorus trichloride under 25 ℃, Triphenyl phosphite is generated; Then heat up to 70 ℃ ventilation with chlorine gas, generated two chlorinated triphenyl phosphate; Again at 50 ℃ water hydrolysis, triphenyl phosphate. The hydrolysate with 5% soda solution for neutralization, water washing, the evaporation and vacuum distillation, collected 243 ~ 245 ℃ (1.47 kPa) fractions, cooling, crystallization, crushing, packaging is the finished product.
Triphenyl phosphite (TPPi antioxidants, stabilizer) is mainly used in PVC, polyethylene, polypropylene, polystyrene, polyester, abs resin, epoxy resin, synthetic rubber antioxidant stabilizer, used in polyvinyl chloride (PVC) products as a chelating agent.
The effect of molecular structure on the antioxidant of industrial organic materials. Ortho group R1, R2 (1) if the influence of R1, R2 volume is larger, the benzene ring and hydroxyl not in the same plane, hinders oxygen P on the electronics and electronic conjugate on the benzene ring, the replace phenol molecules lost due to the effect the stability of the resonance effect, the result is to make hydroxyl H easier to escape. (2) when R1, R2 is too large, the free radicals are not easily accessible to the hydroxyl group due to the obstruction of space, which makes it difficult to capture the effect of free radicals. So R1, R2 shouldn't be too big.
In recent years, studies have shown that R1, R2 for t - Bu, its antioxidant efficiency highest, reason is the large volume of t - Bu stereoscopic protection of phenolic hydroxyl, so most of the performance is hindered phenol antioxidant 2, 6 for tert-butyl replace.
However, recent studies have found that phenol hydroxyl group has a better antioxidant effect with a methyl and a tert-butyl semi - retarded phenol structure. On the one hand, the space resistance of tert-butyl is sufficient to protect the phenolic hydroxyl group. On the other hand, the anti-oxygen reaction rate of the methyl groups on the adjacent side is faster, so the anti-oxygen activity is increased. Moreover, it has an advantage in the combination of NOx stain and sulfur-assisted antioxidant synergism.
The difficulty of having an H out of a position group in R3 is very much affected by R3.
(1) when R3 is an electron absorption group, such as NO2 and COOH, it is easy to get rid of the hydroxyl group without replacing the base.
(2) when R3 is for electronic groups, such as Me, t-bu, it is easy to get rid of the hydroxyl group without replacing the base.
(3) when R3 is a long chain alkyl, it is beneficial to improve the compatibility, thus improving the efficiency of antioxidant.
Molecular structure and compatibility when Rl, R2, R3 are alkyl groups or groups similar to polymer structures, they can increase the compatibility of antioxidants with polymers.
The effect of molecular weight on antioxidant. Polymer materials in the air in 220 ￣ 350 ℃ hot working, must use antioxidants to prevent oxidation in the process of machining.
Therefore, the thermal stability of the antioxidants is very important. In recent years, the research shows that improving the molecular weight is an important means to improve the thermal stability and efficiency of antioxidant. But there is an ideal molecular weight. An antioxidant with ideal molecular weight has the highest efficiency.
After years of research shows that the gm antioxidant its ideal molecular weight between 500 ￣ 1000, as for polymer antioxidants its molecular weight between 1000 ￣ 3000.
Copyright: Zhang Jia Gang YaRui Chemical co.,Ltd
http://www.yaruichem.com
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