Ethyl pyruvate, also known as α- Ethyl ketopropionate, ethyl 2-oxopropionate, molecular formula C5H8O3. Colorless liquid, slightly soluble in water, miscible with ethanol and ether, can be used for food spices such as caramel, brandy, rice wine, rum, chocolate, etc.
Ethyl pyruvate, whose molecular formula is ch3cocooc2h5, also known as ethyl 2-oxo propionate, is a colorless transparent liquid at room temperature, with fresh and sweet flower and fruit aroma, which can be used in the formulation of essence such as apple, citrus, chocolate, etc. It is an extremely important organic synthetic intermediate, which is widely used in medicine (synthetic thiamine drugs), pesticides (herbicides and thiamine fungicides produced by DuPont), food (used as preservatives, preservatives, etc.), cosmetics and other industries.
Ethyl pyruvate has a good effect on inhibiting the formation of tyrosinase in the epidermis, so it can prevent the formation of epidermal melanin and whiten the skin. It can also be added to air fresheners as an efficient active ingredient, which can effectively remove ammonia and methyl mercaptan in the air, and the smell is fresh and natural. Ethyl pyruvate has superior performance in the formation of heterocyclic compounds. It is an irreplaceable raw material and intermediate in the synthesis of pesticides. It is widely used in the synthesis of fungicides and herbicides. Oxazolidone derivatives synthesized from ethyl pyruvate are also a good fungicide. In 5.0 × 10-4 can effectively inhibit and kill fungi.
Pyruvic acid is the main raw material for the production of tryptophan, phenylalanine, proteoglycan and vitamin B. It is the raw material for the biosynthesis of L-dopa (DOPA is used to treat Parkinson's disease). It is the initiator of ethylene polymer and the raw material for the preparation of grain protectants. A highly effective herbicide was synthesized from pyruvic acid. The herbicide has excellent selectivity, good removal effect on weeds such as sedge and Setaria, and is very safe for crops. As a feed and food additive, it has a good anti-corrosion and fresh-keeping function, and a small amount of it is used in the preservation of feed and fruit wine in China. Ethyl pyruvate has a special flavor, which can be used in essence and fragrances. It is also an important raw material for synthetic resins and plastics. Acetone ester products can also be used as special solvents for electronic materials, and the demand for applications in this area is increasing rapidly abroad.
The synthesis methods of ethyl pyruvate mainly include:
(1) With permanganate: Oxidation method with potassium copper sulfate as catalyst: saturated potassium permanganate solution, light petroleum ether, ethyl lactate phosphoric acid_ Sodium hydrogen - stir, cool with ice water bath, pour out petroleum ether after reaction, and distill under reduced pressure to obtain ethyl pyruvate with a yield of about 50%. This method has high cost, low yield, complex post-treatment and serious environmental pollution.
(2) Metal complex catalysis method: in air or oxygen, the complex formed by metal catalysts platinum, silver, vanadium and alumina is used as the catalyst to react at (190- 500) C to obtain ethyl pyruvate.
(3) Bromine catalytic method: using hydrogen peroxide and sodium hypochlorite as oxidants, bromine and sodium bromide as catalysts, oxidize ethyl lactate to synthesize ethyl pyruvate, with a yield of 76% - 89%. The above methods are summarized as ethyl lactate oxidation method. Because the boiling points of the raw ethyl lactate and the product ethyl pyruvate are very close, with a difference of only 1 C, it is difficult to separate, and it is difficult to obtain high-purity products.
(4) Organometallic reagent method 4: triethoxyacetonitrile is dissolved in tetrahydrofuran solution, heated and refluxed, and then the reaction mixture is poured into the mixture of crushed ice and hydrochloric acid to obtain an organic layer, which is distilled under reduced pressure to obtain ethyl pyruvate; The development of this method is limited by the factors of raw materials.
The factory uses pyruvic acid and anhydrous ethanol as raw materials. Under the action of dehydrating agent, continuous dehydration makes the esterification reaction complete; After the reaction, ethyl pyruvate was obtained by distillation under normal pressure and reduced pressure. The reaction equation is as follows:
CH3 COCOOH + CH3CH2OH → CH3COCOOCH2CH3+H2O
The esterification reaction of ethanol and pyruvic acid belongs to nucleophilic addition reaction, which is suitable to be carried out under acidic conditions and is reversible. Therefore, the conversion of pyruvic acid can be improved by ethanol. Therefore, in the experiment, increasing the feeding ratio of ethanol, azeotropic distillation dehydration of the ternary azeotropic mixture of water, ethanol and dichloromethane, increasing the feeding ratio of ethanol, and continuously steaming water at the same time to improve the yield of ethyl pyruvate. The experimental conditions of this method are not high, the operation is simple, and the side reactions are less. It can realize industrial production.
The main uses of ethyl pyruvate are concentrated in the research of pesticides and medical manufacturing, which is not particularly closely related to our daily life, but some daily necessities will use this raw material. Each chemical raw material has its storage method and specific use method, so you can use some leisure time to test and understand. The raw materials involved in the production can choose potassium permanganate and magnesium sulfate solution. The steps of stirring, dripping and cooling can distribute an appropriate amount of ethyl pyruvate. For chemical raw materials that you are not familiar with, you must not contact them with your mouth and nose, because they will be infectious and corrosive to your skin and internal organs, so you must keep a safe distance.