application
1 Used for acylation of alcohols and phenols
The reaction of hydroxyl compounds with anhydride or acyl chloride in pyridine is the most common acylation reaction. But for alcohols with high resistance, the yield is usually low. When using DMAP of catalytic amount, the yield of the reaction can be significantly increased. Pyridine can be completely removed, the reaction conditions are relatively mild, relatively easy to operate, the yield is generally up to 80%~95%.
2 for organophosphorus acylation reaction
The acylation reaction of organophosphorus is the most common basic reaction in chemical synthesis of pesticides. DMAP catalysis can significantly improve the yield of the reaction.
3 for the synthesis of pyrimidine phosphorus oxide
Pyrimidine oxyphosphate is an organophosphorus insecticide developed in China in the 1970s. Mainly with diethyl thiophosphoryl chloride (referred to as ethyl chloride) and 2-methoxy-4-methyl-6-hydroxy-pyrimidine as raw material synthesis of this variety, with trimethylamine as a catalyst for the completion of the catalytic reaction, but the yield is only about 85%. Now after using DMAP as catalyst, Na2CO3 as acid binding agent, ethyl acetate as solvent, the yield has been greatly improved, up to 99.6%, reaction time has also been greatly improved, from the original 4 hours to 2 hours, which provides conditions for large-scale industrial production, so, DMAP for organic phosphine insecticide, The industrial production of this pesticide has made a great contribution.
4 for the synthesis of quinthiophos
Quinalphos is also an organophosphorous insecticide with the generic name Quinalphos. The insecticide is mainly made from ethyl chloride and 2-hydroxyl quinpiprid by mutual reaction. At the beginning of preparation, triethylamine was mainly used as the catalyst. At this time, the yield was only about 65%~70%, which was low and could not achieve large-scale industrial production. Later, it was gradually found that when DMAP was used as catalyst, the yield could be greatly improved, up to 75%~85%, which provided conditions for large-scale industrial production.
Compared with traditional pyridine acylation catalyst, DMAP catalyst has the following advantages:
Fast reaction speed (4 orders of magnitude higher than pyridine), thus can greatly shorten the reaction time, improve labor productivity;
Low reaction temperature, mild conditions, easy to control, easy to operate;
The reaction yield is high and the product purity is high. For alcohols with high steric hindrance, acylation effect is better, and some reactions difficult to be carried out under general conditions can be completed.
Can be used in a wide range of solvents, such as benzene, toluene, dichloromethane, chloroform, tetrahydrofuran, ethyl acetate, acetic anhydride, pyridine and triethylamine can react (slightly soluble in hexane and cyclohexane, slightly soluble in water);
Small dosage, less side reaction, small odor.
Synthetic
The main methods for synthesizing 4-DMAP in industry are:
(1) 4-cyanopyridine method [6]: This method takes 4-cyanopyridine as the main raw material, and first quaternizes with 2-vinylpyridine to obtain the intermediate, then reacts with dimethylamine, and finally the target compound 4-DMAP is obtained by alkali treatment.
Reactive:
(2) Dipyridine salt method [7]: Using pyridine and sulfiside chloride as raw materials, the intermediate 4-(4-pyridine) pyridinium chloride hydrochloride is first prepared, and then reacted with dimethylamine or dimethylformamide (DMF) to produce 4-DMAP. This method is now widely used in industrial production.
Reactive:
Toxicological data [8]
Acute toxicity:
Rat oral meridian LD50:250mg/kg;
Mouse oral meridian LDL0:470mg/kg;
Oral LD50 140mg/kg(RAT);
Skin LD50 90mg/kg(RBT);
Severe Unknown MG /4H(RBT)
Main irritant effects:
Above skin: Caustic effect on skin and mucous membranes.
Above the eye: strong corrosive effect.
Sensitization: There is no known sensitization.
Store [9]
Relatively stable properties; Store at room temperature;
Irritating and corrosive to skin, avoid contact with oxides, acids and water;
Store in a cool, dry place and keep container sealed.
The news information published on this platform is only provided as knowledge for the reference and exchange of industry insiders, without guaranteeing its accuracy and completeness. You should not use this as a substitute for your own independent judgment and therefore any information is at your own risk. If there is infringement, please contact us to delete!
