Synthesis And Application Of2,3-dihydroxy Methyl-2,3-dinitro-1,4-butanediol Derivatives

Nitrate and azides synthesized from polyols were used widely as new energetic plasticizer. Plasticizers derived from polyols fatty acid ester with good lubricity and oxidation stability. But due to its inert chemical property, it could cause certain energy loss of system when as a kind of plasticizer, which limited its application in energetic materials field.2,3-bis(hydroxymethyl)-2,3-dinitro-1,4-butanediol(BHDB) compared with general polyols have a symmetrical molecular structure and contain two groups of-O2. It can be used to synthesize nitrate、azides and fatty acid ester derivatives. These products used as plasticizers and cladding materials to modify explosives properties can provide extra energy for systerm.In this paper,2,3-bis(hydroxymethyl)-2,3-dinitro-1,4-butanediol tetranitrate (BHDBT),1,4-diazido-2,3-bis-azidomethyl-2,3-dinitro-butane (DBADB),1,4-di(azidoacetoxy)-2,3-di (azidoacetoxymethyl)-2,3-dinitro-butane (BDAA),2,3-bis(hydroxymethyl)-2,3-dinitro-1,4-butanediol tetralaurate (BHDBTL),2,3-bis(hydroxymethyl)-2,3-dinitro-1,4-butanediol tetra-palmitate (BHDBTP),2,3-bis(hydroxymethyl)-2,3-dinitro-1,4-butanediol tetrastearate (BHDBTS) and2,3-bis(hydroxymethyl)-2,3-dinitro-1,4-butanediol tetra(12-hydroxyl stearate)(BHDBTHS) were synthesised from BHDB,and their structures were characterized. These compounds were used to modification research of typical energetic materials.BHDB was synthesized from nitromethane by steps of condensation, cyclization, oxidative coupling and hydration. The influence of various factors on the reaction yield was analyzed, and the yield of BHDB was47%at the optimal condition. Acetic anhydride and nitric acid were used as nitrating agent to synthesized BHDBT from BHDB, and the results showed that the quantity of acetic anhydride, preparation temperature and storing time of nitration agent of acetic anhydride-nitric acid are key factors, and the yield of BHDBT was83%; DBADB(BDAA) was synthesized from BHDB by steps of sulfonation (esterification) and azide reaction for the first time. The influence of various factors on reaction yield was studied, and the yield of DBADB (BDAA) was67%(68%) at the optimal condition; The esterification raction catalyzing by4-dimethylaminopyridine (DMAP)/N,N’-dicyclohexylcarbodie(DCC) between BHDB and higher fatty acid was conducted. The reaction products BHDBTL, BHDBTP, BHDBTS and BHDBTHS were obtained at room temperature with yield of80%.This method had many advantages:low reaction temperature, mild condition, high yield.The thermal decomposition activation energy of BHDBT was calculated respectively by the methods of Ozawa, KAS and iteration. The thermal decomposition mechanism function of BHDBT was deduced by the method of integration. The results showed that the thermal decomposition activation energy of BHDBT is133.23kJ-mol-1, and it belongs to chemical reaction mechanism. The mechanism function is f(a)=(1-α)2. The composite explosives based on BHDBT were prepared with mass fraction3%,8%,10%TNT respectively through aqueous suspension method.and the results showed that thermal stability and decomposition heat of the mixture of BHDBT and10%TNT increase slightly. The particle size of mixture distributed uniformly and largen obviously.Full geometrical optimization calculation were carried out for BDADB and BDAA at the level of B3LYP/6-31+G(d,p) based on density functional theory. The results showed that the energy of their occupied orbits were negative and the molecules were stable; Their theoretical density were1.63g·cm-3and1.65g·cm-3calculated by methord of Monte-Carlo. BDADB and BDAA were mixed with AP, RDX and HMX in the mass ratio of1:3respectively. The results showed that the temperature of high temperature decomposition peak of AP coated with BDADB and BDAA decreased by26.78℃and52.85℃respectively, the apparent decomposition heat increased by131.98J·g-1and539.5J·g-1respectively; In addition, the temperature of decomposition peak of RDX coated with BDADB and BDAA decreased by2.5℃and21.04℃respectively, and the decomposition heat increased by367.24J·g-1and88.28J·g-1respectively; the temperature of decomposition peak of HMX was not affected by BDADB and BDA, but they steepened the exothermic decomposition peak of HMX. According to the TG curves of BDAA at different heating rates, Ozawa’s method was used to obtain the activation energies of two reaction stages. And in the process of determining the reaction mechanism function, it was found that the reaction mechanisms of two reaction stages are same, which belonged to the random nucleation and subsequent growth mechanism whose mechanism function was f(a)=1/4(1-a)[-ln(1-a)]-3Ammonium nitrate was coated by BHDBTL, BHDBTP, BHDBTS through liquid phase separation coating technique. The hygroscopicity and crystal change of coated and uncoated ammonium nitrates were studied. And the results showed that BHDBTL, BHDBTP, and BHDBTS all can inhibit Ⅲ-Ⅱ phase transformation and moisture absorption for ammonium nitrate. The best condition for modifying ammonium nitrate is BHDBTS with the quantity of2%. All the samples based on RDX or HMX coated with mass fraction of3%or5%addition of BHDBTL, BHDBTS, BHDBTHS respectively. And the results showed that the specific surface area of coated RDX (HMX) enlarged observably, but the particle size decrease signally; the decomposition heat of coated RDX increased observably, for addition of BHDBTHS, the heat increased to1912.54J·g-1. The decomposition heat of HMX coated with3%BHDBTHS was1541.30J·g-1. The impact sensitivity of RDX coated with5%BHDBTL, BHDBTS and BHDBTHS were28%,48%,52%respectively and the friction sensitivity were20%,60%,48%respectively. The impact sensitivity of HMX coated with5%BHDBTL, BHDBTS and BHDBTHS were42%,68%,32%respectively and the friction sensitivity were76%,60%,90%respectively.