CN104294366A - Cultivation method of centimeter-level HMX monocrystals - Google Patents

Abstract

The invention belongs to the technical field of cultivating HMX crystals, and particulalry relates to a cultivation method of centimeter-level HMX monocrystals, mainly aiming to solve the problems that crystals in the current HMX monocrystals cultivation are small in size and more in deflects. The cultivation method of centimeter-level HMX monocrystals comprises the following steps: (1) preparing an HMX saturated solution in acetonitrile, filtering and collecting filtrate into a conical flask, and sealing the conical flask into an incubator; (2) cooling, namely in the first-stage, cooling the preparation temperature to 45DEG C at the speed of 1DEG C/30min, in the second stage, cooling to 40DEG C from 45DEG C at the speed of 1DEG C/1h, in the third stage, cooling to 28DEG C from 40DEG C at the speed of 0.1DEG C/5min-0.1DEG C/10min, and in the fourth stage, cooling to room temperature from 28DEG C at the speed of 0.1DEG C/10min-0.1DEG C/30min; and (3) standing for 24-48h after cooling to room temperature.

Description

A kind of cultural method of centimetre-sized octogen monocrystalline

Technical field

The invention belongs to octogen crystal cultural method technical field, be specifically related to a kind of cultural method of centimetre-sized octogen monocrystalline.

Background technology

Cyclotrimethylene trinitramine (RDX) and octogen (HMX) are most widely used two kinds of explosives at present.RDX is also known as onit, and it is clear crystal, fusing point 205 ~ 206 DEG C, relative density 1.816g/cm ³(20.4 DEG C), water insoluble, be slightly soluble in ether and ethanol, slightly high in acetone and chlorobenzene, more soluble in the ring ethyl ketone heated, oil of mirbane and second triol.The mechanical sensitivities such as the shock of Cyclotrimethylene trinitramine and friction are comparatively large, and being applied to and having manufactured detonator, booster grain and primacord fuse, and be widely used as the high energy component of propelling agent and propelling charge, is the conventional high explosive that our times uses.Octogen (HMX) is a kind of high explosive, formal name used at school cyclotetramethylene-tetranitramine, white granular crystallization, molecular weight 296.2, and theoretical maximum density is 1.905g/cm ³, apparent density is 1.89g/cm ³, be homologue with RDX, have α, β, γ, δ tetra-kinds of crystal formations.Wherein beta-crystalline form is stable at normal temperatures and pressures, and α, γ crystal formation is metastable state, and δ crystal formation is unstable.β-HMX uses the most extensive, becomes more readily available desirable crystalline form, is to use one of extensive and the good explosive of over-all properties at present.The research of explosive monocrystalline mainly also mainly concentrates on above these two kinds of explosives, and monocrystalline research needs monocrystalline to reach more than centimetre-sized, and zero defect.

The method of single crystal cultivation is varied, volatilization method as slow in solvent, solvent-thermal method, diffusion process, cocrystallization method etc.The physical and chemical performance of different substances is different, and the solubleness in all kinds of SOLVENTS is different, so each crystal needs the cultural method exploring the macrocrystal being applicable to self.Inst. of Chemical Material, Chinese Inst. of Engineering Physics Li Hong in 2011 treasure adopts the growth of solvent evaporated method research RDX monocrystalline, and RDX crystallization solvent used has a great impact crystal habit, and solvent difference grows the single crystal forms obtained may be far from it.In RDX single crystal growth process, for controlling the problem of lattice defect and solution stress concentration, they are by the early Pleistocene process of online concentration determination technology and the interference technical study growth mechanism of RDX crystal, defect and influence factor, by regulating and optimizing the crystallization conditions such as strength of solution, Tc, evaporation rate of solvent, achieve the control to crystal mass.The method can obtain the good centimetre-sized RDX large single crystal of crystal mass under certain crystallization condition.But the method is not suitable for the cultivation of centimetre-sized HMX crystal, adopt solvent evaporates method to cultivate HMX monocrystalline, occur the situation that HMX monocrystalline is childlike, maximum cultivation crystalline size is less than 1cm; Adopt acetonitrile, dimethyl formamide and acetone to make solvent respectively, methyl alcohol and ether, as diffusion solvent, utilize diffusion process to cultivate HMX monocrystalline, occur that HMX crystal size can only reach about 4mm, and the flaw comprised are many, can not reach the applied research of monocrystalline.

Therefore how to control the gordian technique that defect and stress concentration are single crystal cultivations in crystal growing process, owing to there is heteromorphism, the large single crystal growth of its monocrystalline particularly more than centimetre-sized is very difficult.

In falling temperature method, in the process of growth of crystal, the height of solution temperature decides the speed of growth of crystal, also can change the properties of crystalline matrix, and such as solvent to the solubleness of solute, and then affects the final shape of crystal.When the temperature is low, the solubleness of solvent is less, and crystal growth is comparatively slow, and gained crystal homogeneity is better, and now the growth interface of crystal is smooth, and its growth mechanism is layer growth, and growth velocity is also anisotropic, makes gained crystalline structure more complete.When temperature is higher, soltion viscosity reduces, and mass transfer coefficient increases, and crystalline growth velocity is accelerated, and gained crystal homogeneity is poor, and the growth interface roughen of now crystal, growth mechanism also changes continuous growth into, and growth velocity is isotropic.So the temperature that solution starts to lower the temperature also has a significant impact crystallisation process.This external falling temperature method is cultivated in the process of monocrystalline, and small temperature fluctuation is just enough to, in the crystal of growth, cause some non-uniform areas, for improving the integrity of crystal growth, requires that temperature-controlled precision is high as far as possible.Therefore falling temperature method controls the key of crystal growth is in the process of growth of crystal, selects suitable rate of temperature fall, solution is in metastable region all the time and also maintains suitable degree of supersaturation.

Summary of the invention

There is mainly in current octogen single crystal cultivation the problem that crystalline size is little, flaw is many in the present invention, provides a kind of quality good and size reaches the octogen monocrystal cultivation method of centimetre-sized.

The present invention is the technical scheme taked that solves the problem:

The cultural method of centimetre-sized octogen monocrystalline of the present invention comprises the following steps:

(1) first in acetonitrile solution, octogen saturated solution is configured, configuration temperature is 50 DEG C ~ 60 DEG C, and constant temperature stablizes 1 ~ 2 hour at configuration temperature, and then configuring temperature filtration at temperature, the filter core aperture of filtering is not more than 5 microns, collect filtrate in clean Erlenmeyer flask, filtrate in each Erlenmeyer flask is not less than 300mL, the Erlenmeyer flask sealing of filtrate will be housed, be put in incubator, it is identical that setting cultivation the temperature inside the box and saturated solution configure temperature, after stablizing 0.5 ~ 2 hour, starts cooling at this configuration temperature;

(2) cooling is divided into four-stage: the first stage: drop to 45 DEG C from configuration temperature, rate of temperature fall is 1 DEG C/30min; Subordinate phase: drop to 40 DEG C from 45 DEG C, rate of temperature fall is 1 DEG C/1h; Phase III: drop to 28 DEG C from 40 DEG C, rate of temperature fall is 0.1 DEG C/5min ~ 0.1 DEG C/10min, when filtrate temperature is within the scope of 38 DEG C ~ 36 DEG C, in Erlenmeyer flask, start have crystal to separate out; Fourth stage: drop to room temperature from 28 DEG C, rate of temperature fall is 0.1 DEG C/10min ~ 0.1 DEG C/30min;

(3) when filtrate temperature in Erlenmeyer flask reduces to placement 24 ~ 48h after room temperature, the octogen monocrystalline that size reaches centimetre-sized can be obtained.

The present invention adopts gradient cooling method, and whole culturing process avoids vibrations, and filtrate will leave standstill, and lasts the HMX crystal about needing just to obtain centimetre-sized for 5 days.In order to reach larger HMX crystal, can select when room temperature is lower, as winter carries out, due to the volatility of acetonitrile, being not suitable for the configuration temperature improving saturated solution.But culturing process needs strictly to control rate of temperature fall, and rate of temperature fall is too fast, it is more that nucleus separates out quantity, and limited Dispersion of Solute Matter, in the crystal of too many quantity, is unfavorable for growing up of crystal; Lowered the temperature slow, power consumption consuming time, lowered the temperature slow especially between 40 DEG C ~ 30 DEG C scopes, acetonitrile solution volatilizees, and occurs wall cling phenomenon, and namely crystal is not on the nucleus at the bottom of being gathered in bottle, but the liquid-gas interface of liquid level upper end is separated out, and is attached to above bottle wall, is also unfavorable for growing up of crystal.The octogen monocrystalline that the present invention cultivates, show that crystal growth largest face is greater than 1 centimetre, and crystal regularity is good by crystal orientation analysis, and crystal profile is clear with growth crystal face, and crystal is transparent, and defect almost be cannot see in inside.

Accompanying drawing explanation

Fig. 1 is the picture of the octogen monocrystalline that the embodiment of the present invention 1 is cultivated;

Fig. 2 is the picture of the octogen monocrystalline that the embodiment of the present invention 2 is cultivated.

Embodiment

Embodiment 1

A cultural method for centimetre-sized octogen monocrystalline, step is as follows:

(1) first in acetonitrile solution, octogen saturated solution is configured, configuration temperature is 50 ~ 60 DEG C, for ensureing the saturation ratio of octogen saturated solution, at configuration temperature, constant temperature stablizes 1 hour, and then temperature filtration prevents temperature from reducing at configuration temperature, octogen is separated out, during filtration, filter core aperture is not more than 5 microns, collect filtrate in Erlenmeyer flask, filtrate in each Erlenmeyer flask is not less than 300mL and grows up for crystal to ensure sufficient solute, the Erlenmeyer flask sealing of filtrate will be housed, be put in incubator, it is identical with configuration temperature that the temperature inside the box is cultivated in setting, stablize 1 hour at configuration temperature after, start cooling, whole cooling culturing process will ensure that incubator leaves standstill, avoid shaking,

(2) cooling is divided into four-stage: the first stage: drop to 45 DEG C from configuration temperature, rate of temperature fall is 1 DEG C/30min; Subordinate phase: drop to 40 DEG C from 45 DEG C, rate of temperature fall is 1 DEG C/1h; Phase III: drop to 28 DEG C from 40 DEG C, rate of temperature fall is 0.1 DEG C/5min, when filtrate temperature is within the scope of 38 DEG C ~ 36 DEG C, starts have crystal to separate out in Erlenmeyer flask, and the nucleus number of precipitation is 2 ~ 5 time, and the crystal mass of cultivation is best; Fourth stage: drop to room temperature from 28 DEG C, rate of temperature fall is 0.1 DEG C/10min;

(3) when filtrate temperature in Erlenmeyer flask reduces to placement 24 ~ 48h after room temperature, now octogen crystal is substantially no longer grown up, maximum octogen crystal has reached the crystal of centimetre-sized, can take out, in Erlenmeyer flask, have the indefectible little crystal grain of 2 ~ 3mm size can as the crystal seed cultivating crystal next time.

The crystal prepared is shown in Fig. 1, show that crystal growth largest face is greater than 1 centimetre, and crystal regularity is good by crystal orientation analysis, and crystal profile is clear with growth crystal face, and crystal is transparent, and defect almost be cannot see in inside.

Embodiment 2

A cultural method for centimetre-sized octogen monocrystalline, step is as follows:

(1) first in acetonitrile solution, octogen saturated solution is configured, configuration temperature is 50 ~ 60 DEG C, for ensureing the saturation ratio of octogen saturated solution, at configuration temperature, constant temperature stablizes 2 hours, and then temperature filtration prevents temperature from reducing at configuration temperature, octogen is separated out, during filtration, filter core aperture is not more than 5 microns, collect filtrate in Erlenmeyer flask, filtrate in each Erlenmeyer flask is not less than 300mL and grows up for crystal to ensure sufficient solute, the Erlenmeyer flask sealing of filtrate will be housed, be put in incubator, it is identical with configuration temperature that the temperature inside the box is cultivated in setting, stablize 2 hours at configuration temperature after, start cooling, whole cooling culturing process will ensure that incubator leaves standstill, avoid shaking,

(2) cooling is divided into four-stage: the first stage: drop to 45 DEG C from configuration temperature, rate of temperature fall is 1 DEG C/30min; Subordinate phase: drop to 40 DEG C from 45 DEG C, rate of temperature fall is 1 DEG C/1h; Phase III: drop to 28 DEG C from 40 DEG C, rate of temperature fall is 0.1 DEG C/10min, when filtrate temperature is within the scope of 38 DEG C ~ 36 DEG C, starts have crystal to separate out in Erlenmeyer flask, and the nucleus number of precipitation is 2 ~ 5 time, and the crystal mass of cultivation is best; Fourth stage: drop to room temperature from 28 DEG C, rate of temperature fall is 0.1 DEG C/30min;

(3) when filtrate temperature in Erlenmeyer flask reduces to placement 24 ~ 48h after room temperature, now octogen crystal is substantially no longer grown up, maximum octogen crystalline size reaches centimetre-sized, can take out, in Erlenmeyer flask, have the indefectible little crystal grain of 2 ~ 3mm size can as the crystal seed cultivating crystal next time.

The crystal prepared is shown in Fig. 2, show that crystal growth largest face is greater than 1 centimetre, and crystal regularity is good by crystal orientation analysis, and crystal profile is clear with growth crystal face, and crystal is transparent, and defect almost be cannot see in inside.

Claims (1)

1. a cultural method for centimetre-sized octogen monocrystalline, is characterized in that comprising the following steps:

(1) first in acetonitrile solution, octogen saturated solution is configured, configuration temperature is 50 DEG C ~ 60 DEG C, and constant temperature stablizes 1 ~ 2 hour at configuration temperature, and then configuring temperature filtration at temperature, the filter core aperture of filtering is not more than 5 microns, collect filtrate in clean Erlenmeyer flask, filtrate in each Erlenmeyer flask is not less than 300mL, the Erlenmeyer flask sealing of filtrate will be housed, be put in incubator, it is identical that setting cultivation the temperature inside the box and saturated solution configure temperature, after stablizing 0.5 ~ 2 hour, starts cooling at this configuration temperature;

(2) cooling is divided into four-stage: the first stage: drop to 45 DEG C from configuration temperature, rate of temperature fall is 1 DEG C/30min; Subordinate phase: drop to 40 DEG C from 45 DEG C, rate of temperature fall is 1 DEG C/1h; Phase III: drop to 28 DEG C from 40 DEG C, rate of temperature fall is 0.1 DEG C/5min ~ 0.1 DEG C/10min, when filtrate temperature is within the scope of 38 DEG C ~ 36 DEG C, in Erlenmeyer flask, start have crystal to separate out; Fourth stage: drop to room temperature from 28 DEG C, rate of temperature fall is 0.1 DEG C/10min ~ 0.1 DEG C/30min;

(3) when filtrate temperature in Erlenmeyer flask reduces to placement 24 ~ 48h after room temperature, the octogen monocrystalline of centimetre-sized is namely obtained.