Download Preparation of spherical DDNP study Liu off on a journey

Preparation of spherical DDNP study
Liu off on a journey
, Yangzong Wei
Mr Lau deposit
, Yan Liwei
Chen Ji
(Chemical Engineering and Environment North University, Taiyuan 030051; 2 Liaoning Huafeng Specialty
Chemicals Co., Ltd., Liaoning Fushun 113003)
Abstract: sodium sulfide and reduction in direct picric acid, hydrochloric acid using a single feeding method, by
independently developed F1 polymorph control agents, to obtain high-quality ball
Shaped Diazodinitrophenol (DDNP), the average particle size is larger than 350μm, 100 mesh retains more than
95%, the bulk density of 0.70 ~ 0.90g/cc.
Detonation with compression pressure greater than 40MPa, good fluidity, the production process does not leave
fine crystalline and explosive dust. Compared to traditional preparation, DDNP process to increases 2% to 3%,
the production process doesn’t require rinsing of fine crystallization process, while using some of the liquor by
recycling process water consumption per unit of product for 30 ~ 35kg / kg (DDNP), industrial production has
been achieved.
1 Introduction
Diazodinitrophenol (diazodinitrophenol, DDNP), is a heavy metals (such as lead)-free primary explosive
compounds, with excellent explosion properties and chemical stability, so, over the years this has been a
civilian explosive products. One of the main primary explosive preparation methods currently on DDNP
abroad uses sodium carbonate and picric acid, and then sodium sulfide reduction to sodium picramate and a
variety of different methods can be used for diazotization such as ammonia salt method, sodium and nearly
twenty years of law
Explosive continued development and improvement of hydrochloric single feeding method, also known as
United
Pyrogallol method.
DDNP produced with these traditional preparation methods, generally has the following three issues which
severely restrict the production and use of DDNP. First, the amount of waste generated in the production
process of DDNP is large, usually 200 ~ 300kg / kg (DDNP), which further comprises a raw alkaline
wastewater, acidic waste water generated during diazotization and when rinsing fine crystalline the wash water
contains a lot of quinones and phenolic compounds in the wastewater, which these organics are strong dyes,
toxic to soil, water, flora and fauna and so likely to cause serious harm. The general method of thorough
wastewater treatment is difficult. Second, because DDNP in the preparation process only gets to have a particle
size of about 150μm, polycrystalline particle is loose and the bulk density is 0.45 ~ 0.68g/cc. The density is
difficult to moderate. Large spherical particles can be sieved but the presence of a large number of very small
crystals of explosive are easy to fly into the air or in the detonator assembly process or stick to the mold wall
hanging on. It is likely to cause accidents, especially when using large-scale automation.
With an increase of production lines, DDNP dispersion of explosive dust can cause great harm. Third,
according to the traditional production of DDNP products, the compaction pressure of only 20 ~ 30MPa in the
detonator charge is inconvenient. Therefore, in the present study, using sodium sulfide directly to reduce picric
acid, with hydrochloric single feeding method and use self-developed polymorph control agent F1 DDNP.
2 Preparation principle and preparation process
2.1 Principle of preparation
Picric acid is directly used in the preparation and reduction with sodium sulfide solution to sodium picramate,
and diazotization to obtain DDNP, the synthesis reaction is as follows:
The first step in the reaction:
２Ｃ６Ｈ２（ＮＯ２）３ＯＨ ＋Ｎａ２Ｓ→ ２Ｃ６Ｈ２（ＮＯ２）３ＯＮａ＋Ｈ２Ｓ
Ｈ２Ｓ＋２ＮａＯＨ→ Ｎａ２Ｓ＋２Ｈ２Ｏ
The second step reduction reaction:
４Ｃ６Ｈ２（ＮＯ２）３ＯＮａ＋６Ｎａ２Ｓ＋７Ｈ２Ｏ→
４Ｃ６Ｈ２（ＮＯ２）２（ＮＨ２）ＯＮａ＋３Ｎａ２Ｓ２Ｏ２ ＋６ＮａＯＨ
The third step diazotization reaction:
Ｃ６Ｈ２（ＮＯ２）２（ＮＨ２）ＯＮａ＋ＮａＮＯ２ ＋２ＨＣｌ→
Ｃ６Ｈ２（ＮＯ２）２Ｎ２Ｏ＋２ＮａＣｌ＋２Ｈ２Ｏ
2.2 Preparation Process
DDNP Prepared by the process shown in Figure 1.
2.2.1 340kg water was added and the reaction vessel, then add 37 ~
40kg picric acid (dry volume), heated to 50 ~ 55 ℃, for 5 ~ 10min
The dropping 12.5% to 13% of the sodium sulfide solution, keeping the pH of the material
8 to 9, continue the reaction 5 ~ 10min, and filtered to give sodium picrate solution.
Hydrogen sulfide gas is generated during the reaction and with fans is pumped into dilute alkali absorber for
absorption.
2.2.2 Reduction
The mother liquor was filtered into the reduction reactor with the sodium picrate, the temperature was increased
to 56 ~
60 ℃, dropping 175 ~ 180kg sodium sulfide solution within 20min, following the continued stirring for 10min,
cooled to below 35 ℃, the material filtered to give sodium picramate. The alkaline liquor was portioned in
batches of wastewater tank, recycling with part of the mother liquor.
2.2.3 diazotization
Sodium picramate was added to 200kg of water in the compounds vessel. F1 additive was added at 2 ‰ ~ 3 ‰
of amount of sodium picramate, it was heated to 30 ~ 32 ℃, adding 12.5 ~ 13kg sodium nitrite, dropping 8% ~
10% hydrochloric acid. After the reaction, pour off the mother liquor, DDNP was washed with a small amount
of water 2 to 3 times, filtered and dried.
3 Results and discussion
3.1 Select and methods
DDNP conventional process uses sodium carbonate in the heat above 80 ℃ Picric acid to become soluble in
water. After filtration with sulfur solution of sodium reduction reaction, the produced sodium picramate
(referred to hereinafter as ammonium salt) is generally firewood bundle-like crystals, tiny miscellaneous Feng
Jian Chaos, quantity, is not conducive to diazotization. The use of sodium sulfide directly in picric acid, when
the reaction liquid changed from yellow to red transparent, when changed the pH value of 8 to 9, marks the end
of the reaction. A small amount of impurities was filtered picric continue to react with sodium sulfide solution,
using a similar work with the traditional process. Process conditions for the reduction reaction, the resulting
ammonium salt crystals are thick, wedge-shaped blocks conducive to diazotization. With Na2S, the ammonium
salt cake prepared with sodium carbonate and the ammonium salt obtained by the process of nearly one-third of
the volume is reduced, the filtration time of the liquor Shorten the cake moisture content is 27% to 30%, so that
the use of sodium sulfide Step in and complete the picric acid and ammonium salt reduction can not only
improve the crystalline Quantity, but also can reduce the participation reactive substances. After the reduction
reaction mother Liquid can be recycled time use, will not be affected product quality, while significantly
Was reduced alkaline wastewater. Hydrogen sulfide gas that escaped during the reaction was absorbed in 10%
to 20% sodium hydroxide solution.
3.2 Sodium picramate crystalline control
Ammonium salt crystals effected notably by the reaction temperature, the feed rate, concentration of sodium
sulfide solution. By laboratory 2000mL three bottles, constant pumping sodium sulfide solution four o'clock
feeding methods, stirring speed was constant at 300 ~ 400rpm, trials to yield ammonium salts and ammonium
salts of the crystalline quality.
Comprehensive evaluation, take three factors and three levels orthogonal test of reaction
Temperature, sodium sulfide solution concentration, feeding time these three factors were recorded as:
A, B, C on the yield of ammonium salts and ammonium salts of the crystalline quality. Orthogonal test
Experience factor levels are shown in Table 1, the orthogonal experiment results shown in Table 2. According
to Table 2
Orthogonal test results that: poor value for the size relationship between the various factors:
ｌｅｖｅｌ ｔｅｍｐｅｒａｔｕｒｅ ｆａｃｔｏｒｓｃｏｎｃｅｎｔｒａｔｉｏｎ ｃｈａｒｇｉｎｇｔｉｍｅ
／℃
ｏｆＮａ２Ｓ／％
／ｍｉｎ
Ａ
Ｂ
Ｃ
１
５０～５５
１１．５
１５
２
５５～６０
１２．５
２０
３
６０～６５
１３．５
２５
Ｎｏ．
Ａ
Ｂ
Ｃ
１
２
３
４
５
６
７
８
９
Ｋ１
Ｋ２
Ｋ３
Ｒ
１
１
１
２
２
２
３
３
３
８２．６
８４．５
７９．６
４．９
１
２
３
１
２
３
１
２
３
８１．７
８４．０
８１．０
３．０
１
２
３
２
３
１
３
１
２
８０．８
８２．５
８３．３
２．５
ｙｉｅｌｄ／％
（Ｃ６Ｈ２（ＮＯ２）２（ＮＨ２）ＯＮａ）
８０．５
８５．６
８１．７
８３．４
８７．２
８２，８
８１．１
７９．２
７８．４
So of the various factors on sodium picramate the size of the impact is: A> B> C. A factor for the three levels
of efficiency
Should the value of k
2> K1> K3, Take the first two levels, i.e., A2, Empathy B take B2, C Take C3, So the optimum conditions for
the reduction process: A2 B2 C3. That reaction temperature of 55 ~ 60 ℃, sodium sulfide concentration of the
solution was 12.5% and feeding time for 25min. Reaction liquor alkalinity should be strictly controlled,
alkalinity large capacity
Easy to produce in a white leather base material surface, while more azo impurities mixed in
Influence of ammonia salt crystals diazotization due in ammonia salt filtration process Amount drained liquor,
ammonium salt crystals when stout, filtration fast, do not And then washed with water.
Because the sodium picramate reduction is an exothermic reaction, the addition point may be scattered
To avoid local violent reaction, the stirring speed is kept appropriate to make a dropwise rapid dispersion of
sodium to the reaction solution, but it is easy to excessively and break ammonia salt crystals.
Reduction through strict control of the reaction conditions, the alkaline liquor can be recycled to make
With ammonia salt crystal quality is not affected, while a significant reduction in the base
Wastewater volume. Pot liquor recycling program was first dispersed picric acid with fresh
Water, the second and third pan pot for each half of the first mother liquor with each pot produced
Liquor (including some washed with water) by 650 ~ 700kg meter, three pot scrap
The total amount of water is about 1300 ~ 1400kg, while DDNP yield about three pot
70kg, per kg of alkaline wastewater DDNP is 18 ~ 20kg, and pass
Process of alkaline wastewater system is 45 ~ 60kg / kg (corresponding DDNP Product cost).
3.3 diazotization reaction conditions control
3.3.1 pH influence on the diazotization reaction
DDNP was synthesized using a single feed Hydrochloric acid, the reaction starting materials
a significant impact on the pH value of the diazotization, if environment is pH≥8
reaction, the resulting product is not pure started DDNP, but with ammonia DDNP
Conjugate salts of these compounds will be mixed to serious crystallization DDNP
Impact of product purity. Therefore, diazo vessel, with water After the ammonia salts and polymorphs control
agent dispersed, should first feed solution with pH Hydrochloric acid transferred close to neutral, and then
adding sodium nitrite, to be heated salt drops
Acid diazotization. In the course of the reaction due to the excess of nitrite
Sodium, dropping hydrochloric acid and sodium nitrite quickly generate nitrous acid, substantially all
The diazotization reaction of nitrite participation points, a small amount of decomposition of nitrous escape
Nitrogen oxides, pH value of the reaction mass will be maintained at 5.6 to
5.8, then the resulting crystalline form under the action of DDNP controlling agent,
Continuous nucleation and crystallization grow up, should be strictly controlled dropping of hydrochloric acid
Volume, pH of less than 5 The needle-like crystals, pH generates size is not more than 6
Uniform particle, and a polycrystalline.
Influence of temperature on the diazotization reaction
3.3.2 Unlike other diazo reaction, DDNP diazotization reaction temperature
Degrees may be performed at a temperature above 25 ℃. When the reaction temperature is lower,
The reaction is slow, resulting in the escape of the high proportion of nitrous acid, the reaction mass
The stoichiometric imbalance, but increasing the coupling diazo amino compounds and amino
Other byproducts generated nitrogen compounds, DDNP reduce the purity;
The reaction temperature is high, diazotization reaction speed, small dense crystalline DDNP
Real impact detonation capability. The reaction temperature is 26 ℃, 28 ℃, 30 ℃,
32 ℃, 34 ℃ comparing the experimental results are shown in Table 3, you can see
Out: increasing the reaction temperature is conducive to improve the density of the product.
3.3.3 polymorphs affect control agent
After years of production practice, pyrogallol is used widely crystal
Control agent, under normal circumstances the addition amount of ammonia salt 2 ‰ ~ 3 ‰,
Join less, yellow Yazi and broken medicine more amount to more than small, dense crystalline
Solid, pressure differential, thereby obtained polycrystalline DDNP ball shape, particle
Loose particle size of about 150 ~ 200μm, as shown in Fig. By large
Experiments on screened out F1 crystalline controlling agent, it is higher in both polar
Organic compounds and a small amount of anionic surfactant compound formed,
Amount of ammonium salt 2.5 ‰ ~ 3.5 ‰, capable of nuclei in DDNP
An outer layer forming the active membrane, which greatly improves the crystallinity of the environment
DDNP, May be prepared by crystallization of high purity spherical DDNP, shown in Figure 5. The
After the glass sheet is pressed in the crystallization DDNP, observed under a microscope, the spherical
DDNP complete crystallization, unlike pyrogallol
[8]
Control agent as a crystalline
DDNP petal-shaped polycrystalline, as shown in Figure 6.
Under the action of F1 polymorph control agent diazotization reaction starts
8 ~ 10min later, DDNP crystalline particles reach a 100μm (Figure 7), the
After 20min, the crystal particles of approximately 300μm (Figure 8), Figure 7 and
As can be seen in Figure 8, around the DDNP many crystalline ammonium salt adsorbed
Crystallization, the product of the reaction to facilitate the rapid diazotized deposited onto the nuclei, so that
DDNP crystal growth possible.
By adjusting F1 polymorph control agent added in an amount of different density can be obtained
Degree DDNP (see Table 4).
When the amount is less than polymorph control agent ammonium salt crystals 2 ‰, product
100 mesh was a high proportion of the crystal is small and most of the powder,
With the increase of polymorphs amount of control agent, DDNP bulk density increase
Added, a 100-mesh sieve was also significantly reduced by adjusting the polymorph control F1
The addition amount of the crystal can be easily controlled in bulk density DDNP ball
DDNP shaped bulk density of 0.75 ~ 0.90g/cc
, The nitrogen-containing
Amount ≥0.28, the yield was 64% ~ 65% (in the amount of picric acid dry basis).
3.3.4 drops of hydrochloric acid and stirring speed acceleration affect crystallization of DDNP
Hydrochloric acid, dropping the speed depends on the quality of ammonium salt crystals, ammonia
Feed rate must be reduced when salt crystals small, otherwise diazotization reaction speed
Too fast, severely eroded ammonium salts, ammonium salts or adhering on many crystals
DDNP small nuclei, resulting in product particles Suixiao, accompanied by severe
Lot DDNP small yellow crystals. Figure 9 is a broken ammonia salt eroded by post
Sheet 10 is adhered to the drug crushed ammonium salt crystals.
When the fast feed rate of the hydrochloric acid, the ammonium salt crystals easily stick
Attached lot DDNP small nuclei, which affects the normal spherical
DDNP crystals formed when the ammonium salt crystals are adhered to the drug-crystalline broken
An appropriate increase in the stirring speed, the adhesive material dispersed into the reaction system, it
Become crystal growth of nuclei. However, the stirring speed is too fast to make the production easier
And ammonium salts of the crystalline material to break, is not conducive to large particles prepared crystals
DDNP
Equipment. Reasonable control of the diazotization reaction conditions, batch crystallization DDNP
100 mesh sieve material up to 95%, due to the large product particle density
High, during the synthesis of fine crystals are formed not, can be carried out by decantation
Washing, eliminating the traditional DDNP rinsing process, not only to improve the
DDNP of yield, while significantly reducing the production of water, according to the alkaline mother
Acidic liquid recycling program recycled mother liquor, can the amount of acidic wastewater
12 ~ 15kg / kg, the traditional process of acidic wastewater for 60 ~ 70kg / kg
(To DDNP crystallization dollars).
4 Conclusions
(1) Preparation of spherical crystals DDNP main conditions are: neutralization
Reduction with sodium sulfide concentration: 12.5%; neutralization temperature: 50 ~ 55 ℃;
Reduction temperature: 56 ~ 60 ℃; diazotization reaction temperature: 30 ~ 32 ℃;
F1 polymorph control agent amount: 2.5 ‰ ~ 3.5 ‰ (ammonia salt meter);
Yield ≥64% ~ 65% (in the amount of picric acid dry basis); total amount of waste water:
30 ~ 35kg / kg (with DDNP crystallization dollars).
(2) F1 crystal form control agent may significantly improve the crystallization ring DDNP
Environment, so that the sphericity of the product is good, the crystal grain size of 350 ~ 550μm,
Control polymorph control agent can be obtained by adding the amount of bulk density of 0.75 ~
0.90g · cm
-3
Product, crystalline dense, good fluidity, in preparation over
Cheng is not tiny crystals and dust, greatly improving the production and use of safety
Full sex. Meanwhile, the sphere is greater than the pressure resistance of the crystalline DDNP 40MPa,
Compared with conventional polycrystalline DDNP, doubling the pressure resistance. Effective
3.3.5 Pressure experiments DDNP crystal ball
DDNP spherical pressure crystallization experiment conditions were: iron pipe shell straight
Diameter of 6.8mm length 58mm, copper strengthen cap, the main charge Lac granulation
RDX350mg, 70MPa, second charge RDX250mg, 40MPa,
DDNP220mg, combined pressure were 35,40,45,50MPa. Real
Experimental results are shown in Table 5.
As can be seen from Table 5, the pressure of the ball with the dense crystalline DDNP
The rise of the degree of decrease in the density control 0.75 ~ 0.90g · cm
-3
Compared
Ideal.
Solution to the current volume of wastewater DDNP facing explosive dust
Multi-pressure problems and poor, to give a new vitality DDNP.