Synthesis method of 3,4-dicarboxylic acid diethyl ester furoxan

Abstract

The invention relates to a furoxan ring, and provides a synthesis method of 3, 4-dicarboxylic acid diethyl ester furoxan. The method adopts a monoethyl malonate potassium salt as a raw material and takes sodium nitrate / nitrite as an oxidizing agent. The substances are subjected to oxidation nitration and a ring formation reaction in a carbon tetrachloride solution, thus obtaining the target compound 3, 4-dicarboxylic acid diethyl ester furoxan with purity up to 98.7% and yield up to 94.2%. The synthesis method provided in the invention has the advantages of high purity and high yield.

Description

technical field [0001] The invention relates to an oxidized furoxan ring, in particular to a synthesis method of 3,4-diethyl dicarboxylate oxidized furoxan. Background technique [0002] Furoxan ring (Furoxan) is a nitrogen-oxygen five-membered ring with a coordinated oxygen atom. Because the ring contains a "potential nitro group", it becomes an explosive group. Furazan and furoxan derivatives have always been regarded as very useful. Hopeful energetic materials, because of their high nitrogen content, active oxygen and positive standard enthalpy of formation, and high density, are important structural units for the construction of new high-energy compounds. The energetic derivatives with oxyfurazanyl as the explosive group have the following characteristics (1) the oxyfurazanyl can provide a relatively higher energy density; Additives can improve the oxygen balance of the system; (3) Furazanyl oxide can endow its derivatives with ring tension and high standard enthalpy of...

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Problems solved by technology

The first method is based on EtO 2 CC (NO 2 )=NO 2 K raw material, in N 2 o 4 It is an oxidant synthesis, and the disadvantage of this method is that the cost of raw materials is high and the risk of experimental operation is high, and the product yield obtained by this method is the highest 90%, and the purity is 95% (the yield in the literature is 94%, and there is no purity report); the second The method uses ethyl nitroacetate (EtOOCCH=N(OH)O) as the raw material and copper acetate as the oxidant to synthesize. Compared with the first method, this method adopts a milder oxidant for reaction and overcomes the first method. Unsafe in method operation, but shortcoming is raw material cost height, reaction time is long and yield is low, and data report is only 43%, and there is no purity report; The third method is raw material with ethyl acetoacetate, with nitrous acid Sodium and dilute HNO 3 It is obtained by oxidizing an oxidant into a ring, such as "Synthesis and Characterization of Diaminoazodioxyfuroxan" (Energetic Materials, 2008, 16(1), 53-55), which discloses a 3,4-dicarboxylic acid The synthesis method of diethyl ester oxidized furoxan, the specific operation process is: slowly drop the aqueous solution of sodium nitrite into the mixed solution of ethyl acetoacetate and glacial acetic acid at -10°C, and control the temperature at -5°C. After the dropwise addition, the solution was poured into ice water, extracted with ether, washed with distilled water, the ether phase was separated and removed by rotary evaporation; the remaining solution was poured into a three-necked flask, and then slowly dropped into 0.36mol / L HNO 3 Solution, after the dropwise addition, heated to 80°C and stirred for 20min

After cooling to room temperature, let it stand and separate layers, and separate the light yellow-green oily liquid 3,4-diethyl dicarboxylate furoxan through a separatory funnel, with a yield of 76.9%. The advantages of this method overcome the shortcomings of the first two methods The raw materials used are common and easy to get and the price is low. The disadvantage is that the yield is low, and it is found in actual operation that after the aqueous solution of sodium nitrite is added dropwise and reacted for 1 hour, the product 3 generated by the reaction is detected by liquid chromatography. 4-Diethyl dicarboxylate furoxan product is seldom, mainly raw material ethyl acetoacetate; To reach the yield 76.9% described in the document, need just can reach under the reaction of long time; In addition, this method gained Although there is a report on the yield, there is no report on the purity of the product. However, according to this method, the product of 3,4-diethyl dicarboxylate furoxan is poor in quality and the purity is not higher than 67.6%.

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