megalomania
May 10th, 2003, 12:20 AM
shady mutha
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posted March 22, 2001 05:31 PM
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Among nitrophenols 2,4,6-trinitrophenol-picric acid-is of the greatest importance.The fact that this compound was first obtained as long ago as the mid eighteenth century can be explained by the exceptional ease with which nitro groups can be introduced into the aromatic ring,due to the presence of the phenol group.
Three nitro groups can be introduced by nitrating with nitric acid of relatively low concentration,while concentrated acid enables four and even five nitro groups to be indroduced.
The presence of nitro groups enhances the acidic properties of the phenol group.This is why the trinitro derivatives are also called acids,e.g.trinitrophenol is known as picric acid and trinitroresorcinol as styphnic acid.These compounds readily form salts with metals or bases.
According to Hantzsch,nitrophenols exist in two forms:a phenolic,colorless form 1 and a quinonoid coloured one (form 2a 2b).this occurs with picric acid.
Due to the presence of a phenolic group nitrophenols are soluble in water and their acidic character enables then to dissolve in aqueous solutions of bases with the formation of the corresponding salts.Solutions of the salts are usually brightly colored due to the presence of form2.
Of all the nitrophenols,picric acid has been known the longest.The first mention of it can be found in alchemical writings of 1742,in which(cant read it)experiments are described.He acted with nitric acid on wool or horn and isolated picric acid in the form of its lead or potassium salt.A more detailed description was given by Woulfe in 1771,who prepared picric acid from indigo by treating it with nitric acid and found that the new substance had dyeing properties("indigo yellow")while Haussmann,in 1788,proved that it behaved like an acid.Later,many workers obtained the same product by acting with nitric acid on various organic substances,such as silk,natural resins ect.Welter;Braconnot.Chevreul was the first to express the opinion that picric acid contained certain constituents of nitric acid and this was later confirmed by Dumas and Marchand.The latter gave C12H6N6O14 as the empirical formula of picric acid which is exactly double the correct formula.
Some of the authors had drawn attention to the explosive character of picric acid salts,but it was not until 1830 that Welter suggested the possibility of applying picrates as explosives.At that time picric acid was obtained solely by acting with nitric acid on indigo.Marchland expressed the view,which proved to be true,that it was aniline,formed as an intermediate product in the process of decomposition of indigo,silk and other organic matter,which yielded picric acid under the influence of nitric acid.
In the second half of the nineteenth century,picric acid was very widely used as a fast dye for silk and wool.The first definite suggestions as to the application of picric acid for the manufacture of explosives go back to the early second half of the nineteenth century.They referred to the application of picric acid salts as by then the explosive properties of picrates were already well known.
The view then prevailed,supported by such an authority as Abel,that picric acid itself is not explosive but only its salts are.Nevertheless in 1873 Sprengel proved that picric acid could be brought to explosion by a detonator andTurpin proposed applying the property of picric acid by utilizing it for filling shells.In Russia methods of preparation of picric acid and using it as a shell filling were worked out near 1894 by Panpushko.Eventually picric acid was accepted all over the world as the basic high explosive for military uses.
Since picric acid melts at high temperature,shells are loaded by pouring it in mixed with various nitro compoundsinirophenol,mono-and di-nitronaphthalenes,TNT,TNX ect.
shady mutha
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posted March 22, 2001 07:36 PM
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Picric acid decomposes according to the equation(Kast)
16C6H30(NO2)3=32CO2+40CO+4CH4+2H20+3C2H2+3HCN+4.5H 2+21.5N2+2NH4HCO3+9C
Its heat of explosion is 1000kcal/kg,the volume of gases produced Vo=675.1/kg and temperature t=3230.c.
Accordind to Schmidt heat of explosion=960kcal/kg,the volume of gases Vo=737 1./kg=3530.c.
R.Robertson and Garner found the heat of explosion to be 910-935kcal/kg,and the volumeof gases Vo=725 1./kg.
The impact sensitivity of picric acid is higher than that of TNT.In many countries the value of 100 had been taken for the sensitiveness of picric acid,sensitiveness of other explosives being expressed in terms of that of picric acid.Thus the value for tetyl will be 70 and that for tnt-115-275,according to various authors.
The sensitiveness of picric acid to friction is low,but slightly higher than that of TNT.
The expansion produced in the lead block,as reported by various authors is 250-350ml.Taking the value for TNT as 100,that for picric acid will be 102-120.
In the mortar test picric acid gives a value of 110-120,and in the sand test 104,relative to TNT=100.
rate of detonation according to Kast
Density m/sec
1.30 5980
1.41 6465
1.49 6885
1.50 7110
According to Friedrich
0.7 4020
0.9 4635
1.30 6190
1.54 6930
According to Roth
1.1 4560
1.23 5430
1.41 6940
1.56 7504
Cybulski found the rate to be 7260m/sec at a density of 1.7g/cm3.As the highest rate of detonation values from 7100-7500 m/sec are accepted
shady mutha
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posted March 22, 2001 11:16 PM
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Picric acid is produced either by nitrating phenol or by nitrating dinitrophenol prepared by hydrolysis of chlorodinitrobenzene.
The process is effected in two stages.Phenol is first sulphonated and then the sulphonation product is nitrated with nitric acid.
Two features of the process may justify its use.First of all,direct nitration of phenol with a nitrating mixture may lead to the formation of various by products resulting from oxidation,condensation,resinification ect which will contaminate the product and lower its yield.In addition,when two separate stages are used-sulphonation and nitration-it is possible to carry out the nitration without any excess of acids,so that the spent acids left after separation of the product may be discharged into the drainage system without further treatment.This is of great importance,principally because the acids are not suitable for concentration as they contain picric acid.picric acid is known to be rather volatile and may escape from sulfuric acid solutions if in the concentration process the H2SO4 content becomes higher than 72.5%.Picric acid is vapors,after being condensed on metal parts of the equipment,may form picrates,for example,with lead or iron,which explode readily
shady mutha
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posted March 23, 2001 03:11 PM
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These are primitive methods(applied during 1914-1018 in Russia,France,Italy and Great Britain),which gained considerable popularity,solely because they enabled large scale production to be achieved rapidly by the hitherto unprepared allied powers.
The main part of the operation consisted in nitrating sulphonated phenol with materials readily available in those days-dilute nitric acid and sodium nitrate.To prevent ant corrosion of the nirtrators and to prevent and possible formation of metal picrates,the nitrators were built of stone-ware.
shady mutha
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posted March 23, 2001 05:17 PM
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The first stage of the production process-the preparation of phenolsulphonic acid-may be effected in various ways.
Pascal describes it as follows.Phenol,which is supplied in iron drums,is melted by placing the drums,after removing their lids and bottoms,into steam heated cylinders.Molten hot(80.c)phenol is collected in the heated tank which also acts as a proportioner.Adjacent to it,is a tank for 92%sulphuric acid.Both liquids flow down to the sulphonater,designed for 150-250kg of phenol.For 100 parts of phenol 500 parts of sulphuric acid is used.The phenol in the sulphonator being hot,the sulphonation reation starts spontaneously,resulting in a temperature rise to 100.c.After some 10-20 min,sulphonation may be regarded as completed and hot"sulphophenol"is transferred by means of a pressure egg to the nitrator.The pipeline for conveying the product should be heated,otherwise the phenolsulphonic acids are likely to crystallize.
According to Lebeddevs description,phenol is sulphonated with 98% sulphuric acid taken in the proportions of 400-500 parts of acid for 100 parts of phenol.The sulphonation temperature is maintained within 70-80.c or 100-110.c.The reaction time is 4hr.A temperature of 125-130 may also be maintained,in which case the reaction time can be reduced to 2 hr.Cast iron sulphonators are used,2 m in diameter and 1.8 high.The required temperature may be maintained in the sulphonator by heating with a steel heating coil or with a heating jacket.
If concentrated(98%)sulphuric acid has been used for the sulphonation,the sulphophenol should be diluted with water prior to nitration,otherwise the nitration reaction may proceed too violently.
The dilution of sulphophenol is effected in special stoneware vessels.for 95kg of sulphophenol 72 L of wash water is added.The specific gravity of the sulphophenol after dilution should be 1.35.The diluted sulphophenol is left to settle and then filtered through a sand filter.The temperature of the sulphophenol which is to be nitrated should not be lower than 50.c,which is necessary for initiating the nitration process.
shady mutha
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posted March 24, 2001 02:24 AM
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The second stage in the manufacture of picric acid is the nitration of the phenol-sulphonic acid(sulphophenol)obtained.The simplest reactors used for this process are stoneware jars,"tourills",which may be of various size(e.g.85cm diameter in the widest part,1.35m in height).The lids of the jars are equipped with two wide entry holes,15cm in diameter,one for feeding the nitrator with acid and sodium nitrate,the other for connecting the nitrator with the ventilating system.In addition to this,three smaller holes in the lid serve for introducing sulphophenol,inserting a compressed air line that reached down to the bottom of the jar and for inserting a thermometer.Naturally,various modifications of the nitrator construction are possible.These jar nitrators have the disadvantage of not being equipped with heating or cooling devices:the heat is supplied by the reaction itself and the required temperature is maintained by adjusting the flow of the reactants.
shady mutha
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posted March 24, 2001 02:13 PM
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To facilitate working and increase output the nitrators are transported in wooden carts from the nitration section to a separate place,where the nitrator contents are allowed to cool prior to their transport to the purification section,where picric acid is separated from the spent acid and washed with water.
Usually the nitrator is tightly enclosed in the cart by a cement layer.This is necessary to isolate and to prevent the nitrator from any damage.Should the jar-nitrator crack because of too high a temperature,the cement layer prevents the reaction mixture from flowing off;sometimes it can even be recovered.
In France nitration was effected in the following way(Pascal)
The jar-nitrator is charged with 275kg of 44% nitric acid or with the mixture:
nitric acid(44%)120kg
sodium nitrate 90kg
To this 180kg of warm 50-70.c sulphophenol(corresponding to 30kg of phenol)is gradually added.At the same time compressed air is passed through the nitrator to mix the reactants well.The rate of addition of sulphophenol should be so adjusted as to prevent the temperature from rising too rapidly at the beginning of the reaction.Hence the sulphophenol should be added carefully at first,although its flow must be rapid enough to attain a temperature of 100.c,at which the main portion of the product nitrates.If the process is operated properly,95-100.c is attained within 20 min from the beginning of the process(initial temperature 25-30.c)After one hour a temperature of 115-120 is attained.All the sulphophenol should be added within one and a quarter hours.By this time the temperature falls to 90-100.c.Then,to remove nitrogen oxides,air is blown through the nitrator for 10-20min and the nitrator is disconnected from the ventilating pipe and transported to the cooling section
shady mutha
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posted March 25, 2001 03:09 PM
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The nitrator contents are stirred repeatedly with a wooden pole while cooling to prevent picric acid from forming lumps which might retain impurities.After cooling for3-4 hr at a temperature of about 60.c,50-100 L. of water is added,thus preventing the precipitation of sodium bisulphate or,if it has already been precipitated,causing it to go into solution.The diluted acid contains some 45% of H2SO4,the concentration at which the solubility of picric acid is lowest.After it has cooled to ambient temperature 12-24 hr,the spent acid is drawn off by a siphon and the picric acid is transported to another section,where it is washed with water.Since the spent acid usually does not contain more than 1% of HNO3,its recovery is pointless.
The contents of 4-5 nitrators(200-300kg of picric acid)are transferred by means of wooden ladles to a wooden washing vat,where picric acid is washed several(mostly five)times with 150-200L.portions of water.For 100kg of picric acid 400L. of water is used.The product is tested for purity by determining the SO42+ ions in a solution of the picric acid in distilled water.After washing picric acid is separed from water in a centrifuge usually made of copper,the water content being brought to 5-7%.
Washings are collected in special wooden tanks for settling.The spent acid is also added to the washings so as to bring the H2SO4 content to 10-30% as in such "acid water"the solubility of picric acid is at its lowest.The water is decanted from time to time and disposed off into the river,after being neutralized,while the settled picric acid is collected from the botton of the tank.
The recovered picric acid usually contains large quanities of mineral matter(determined as ash-0.2%,compared with the permissible limit of 0.03%,as well as H2SO4(0.1 instead of 0.02%)Such a product cannot be used for military purposes without further purification by crystallization from water.
shady mutha
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posted March 25, 2001 04:36 PM
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United States method
During World War I a method of manufacture of picric acid was established in the United States.
Olsen and Goldstein described the method as follows.
302.2kg of phenol are sulphonated with 605 kg 93%sulphuric acid at 95-98.c during 6 hr.The product is composed of 80% phenol-4-sulphonic acid and 20% phenol-2-4-disulphonic acid.
The mixture of phenolsulphonic acids is diluted with 737.5 L. of water.Usually wash-waters are used for this purpose.The concentration of phenolsulphonic acid in the resulting solution is 18.4 calculated on phenol.
nitration is carried out in two stages.In the first stage the nitrator is filled with a nitrating mixture composed of 70% HNO3,10%H2SO4 and 20%H20.The quanity of the mixture corresponds to that calculated for the indroduction of one nitro group.Phenolsulphonic acid is added to the nitrating mixture at 30.c at the beginning and 52.c at the end.During the first stage mononitro derivatives are formed.
After the first stage the temperature in the nitrator is raised to 60.c and the second stage begins.It consists in adding the same nitrating mixture.During the first hour of mixing the temperature increases to 110-115.c.Altogether 1250 kg of nitrating mixture are added(i.e. 2.75 kg of HNO3 for 1 kg of phenol.)
This method is not accompanied by the evolution of large quanity of nitrogen oxides.The nitration is ended when the content of the nitrator changes colour from red(the colour of phenolsulphonic acids)to yellow(the colour of picric acid)
The yield is 667.6 kg of picric acid,i.e. 220% by weight(theoretical yield 243%)
The spent acid contains 1.0 and 1.5% of picric and oxalic acis respectivly.
It is diluted with double its weight of water;water from washing picric acid is beingused.The solution is brought to bioling for 5 hour to transform the remaining nitro-phenolsulphonic acids into picric acid.After cooling,a second crop of picric acis is obtained in quanity 15% by weight of phenol,i.e the total yield is 235% by weight.The losses of picric in the wash waters correspond to 1% of phenol.
shady mutha
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From: australia
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posted March 25, 2001 07:42 PM
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The construction of picric acid driers presents certain difficulties because of the ready formation of picrates.Having this in mind,wood is mostly used as the construction material for driers,and any metal parts(screws nails)should be made either of metals that form picrates with difficulty such as copper or alumimium,or of tinned metals or stainless steel.
Literature:
M.Marqueyrol and P.Loriette,Bull.soc.chim.France 25,371(1919)27,420(1920)
P.Pascal,Poudres,explosifs,gaz de combat,Hermann,Paris,1925
R.King,J.Chem.soc.119,2105(1921)
H.Arundal,G.P Davies ans I.C.I.Ltd,Brit.Pat 370436(1931)
I.V.Lebedev,Proizvodstwo pikrinovoi kisloty,Goskhimtekhizdat,Moskva-Leningrad,1934.
F.Olsen and J Goldstein,Ind.Eng.chem.16,66(1924)
H.s.Reed,Ind.Eng.Chem.16,72(1924)
Technical Records of Explosives Supply 1924-1918,No 6.Manufacture of picric acid,HMSO,London,1921.
R.Wolffenstein and O.Boters,Ger.Pat 194883(1906);Ber.46,586(1913)
Frequent Poster
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posted March 22, 2001 05:31 PM
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Among nitrophenols 2,4,6-trinitrophenol-picric acid-is of the greatest importance.The fact that this compound was first obtained as long ago as the mid eighteenth century can be explained by the exceptional ease with which nitro groups can be introduced into the aromatic ring,due to the presence of the phenol group.
Three nitro groups can be introduced by nitrating with nitric acid of relatively low concentration,while concentrated acid enables four and even five nitro groups to be indroduced.
The presence of nitro groups enhances the acidic properties of the phenol group.This is why the trinitro derivatives are also called acids,e.g.trinitrophenol is known as picric acid and trinitroresorcinol as styphnic acid.These compounds readily form salts with metals or bases.
According to Hantzsch,nitrophenols exist in two forms:a phenolic,colorless form 1 and a quinonoid coloured one (form 2a 2b).this occurs with picric acid.
Due to the presence of a phenolic group nitrophenols are soluble in water and their acidic character enables then to dissolve in aqueous solutions of bases with the formation of the corresponding salts.Solutions of the salts are usually brightly colored due to the presence of form2.
Of all the nitrophenols,picric acid has been known the longest.The first mention of it can be found in alchemical writings of 1742,in which(cant read it)experiments are described.He acted with nitric acid on wool or horn and isolated picric acid in the form of its lead or potassium salt.A more detailed description was given by Woulfe in 1771,who prepared picric acid from indigo by treating it with nitric acid and found that the new substance had dyeing properties("indigo yellow")while Haussmann,in 1788,proved that it behaved like an acid.Later,many workers obtained the same product by acting with nitric acid on various organic substances,such as silk,natural resins ect.Welter;Braconnot.Chevreul was the first to express the opinion that picric acid contained certain constituents of nitric acid and this was later confirmed by Dumas and Marchand.The latter gave C12H6N6O14 as the empirical formula of picric acid which is exactly double the correct formula.
Some of the authors had drawn attention to the explosive character of picric acid salts,but it was not until 1830 that Welter suggested the possibility of applying picrates as explosives.At that time picric acid was obtained solely by acting with nitric acid on indigo.Marchland expressed the view,which proved to be true,that it was aniline,formed as an intermediate product in the process of decomposition of indigo,silk and other organic matter,which yielded picric acid under the influence of nitric acid.
In the second half of the nineteenth century,picric acid was very widely used as a fast dye for silk and wool.The first definite suggestions as to the application of picric acid for the manufacture of explosives go back to the early second half of the nineteenth century.They referred to the application of picric acid salts as by then the explosive properties of picrates were already well known.
The view then prevailed,supported by such an authority as Abel,that picric acid itself is not explosive but only its salts are.Nevertheless in 1873 Sprengel proved that picric acid could be brought to explosion by a detonator andTurpin proposed applying the property of picric acid by utilizing it for filling shells.In Russia methods of preparation of picric acid and using it as a shell filling were worked out near 1894 by Panpushko.Eventually picric acid was accepted all over the world as the basic high explosive for military uses.
Since picric acid melts at high temperature,shells are loaded by pouring it in mixed with various nitro compoundsinirophenol,mono-and di-nitronaphthalenes,TNT,TNX ect.
shady mutha
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From: australia
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posted March 22, 2001 07:36 PM
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Picric acid decomposes according to the equation(Kast)
16C6H30(NO2)3=32CO2+40CO+4CH4+2H20+3C2H2+3HCN+4.5H 2+21.5N2+2NH4HCO3+9C
Its heat of explosion is 1000kcal/kg,the volume of gases produced Vo=675.1/kg and temperature t=3230.c.
Accordind to Schmidt heat of explosion=960kcal/kg,the volume of gases Vo=737 1./kg=3530.c.
R.Robertson and Garner found the heat of explosion to be 910-935kcal/kg,and the volumeof gases Vo=725 1./kg.
The impact sensitivity of picric acid is higher than that of TNT.In many countries the value of 100 had been taken for the sensitiveness of picric acid,sensitiveness of other explosives being expressed in terms of that of picric acid.Thus the value for tetyl will be 70 and that for tnt-115-275,according to various authors.
The sensitiveness of picric acid to friction is low,but slightly higher than that of TNT.
The expansion produced in the lead block,as reported by various authors is 250-350ml.Taking the value for TNT as 100,that for picric acid will be 102-120.
In the mortar test picric acid gives a value of 110-120,and in the sand test 104,relative to TNT=100.
rate of detonation according to Kast
Density m/sec
1.30 5980
1.41 6465
1.49 6885
1.50 7110
According to Friedrich
0.7 4020
0.9 4635
1.30 6190
1.54 6930
According to Roth
1.1 4560
1.23 5430
1.41 6940
1.56 7504
Cybulski found the rate to be 7260m/sec at a density of 1.7g/cm3.As the highest rate of detonation values from 7100-7500 m/sec are accepted
shady mutha
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From: australia
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posted March 22, 2001 11:16 PM
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Picric acid is produced either by nitrating phenol or by nitrating dinitrophenol prepared by hydrolysis of chlorodinitrobenzene.
The process is effected in two stages.Phenol is first sulphonated and then the sulphonation product is nitrated with nitric acid.
Two features of the process may justify its use.First of all,direct nitration of phenol with a nitrating mixture may lead to the formation of various by products resulting from oxidation,condensation,resinification ect which will contaminate the product and lower its yield.In addition,when two separate stages are used-sulphonation and nitration-it is possible to carry out the nitration without any excess of acids,so that the spent acids left after separation of the product may be discharged into the drainage system without further treatment.This is of great importance,principally because the acids are not suitable for concentration as they contain picric acid.picric acid is known to be rather volatile and may escape from sulfuric acid solutions if in the concentration process the H2SO4 content becomes higher than 72.5%.Picric acid is vapors,after being condensed on metal parts of the equipment,may form picrates,for example,with lead or iron,which explode readily
shady mutha
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Posts: 149
From: australia
Registered: SEP 2000
posted March 23, 2001 03:11 PM
--------------------------------------------------------------------------------
These are primitive methods(applied during 1914-1018 in Russia,France,Italy and Great Britain),which gained considerable popularity,solely because they enabled large scale production to be achieved rapidly by the hitherto unprepared allied powers.
The main part of the operation consisted in nitrating sulphonated phenol with materials readily available in those days-dilute nitric acid and sodium nitrate.To prevent ant corrosion of the nirtrators and to prevent and possible formation of metal picrates,the nitrators were built of stone-ware.
shady mutha
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Posts: 149
From: australia
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posted March 23, 2001 05:17 PM
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The first stage of the production process-the preparation of phenolsulphonic acid-may be effected in various ways.
Pascal describes it as follows.Phenol,which is supplied in iron drums,is melted by placing the drums,after removing their lids and bottoms,into steam heated cylinders.Molten hot(80.c)phenol is collected in the heated tank which also acts as a proportioner.Adjacent to it,is a tank for 92%sulphuric acid.Both liquids flow down to the sulphonater,designed for 150-250kg of phenol.For 100 parts of phenol 500 parts of sulphuric acid is used.The phenol in the sulphonator being hot,the sulphonation reation starts spontaneously,resulting in a temperature rise to 100.c.After some 10-20 min,sulphonation may be regarded as completed and hot"sulphophenol"is transferred by means of a pressure egg to the nitrator.The pipeline for conveying the product should be heated,otherwise the phenolsulphonic acids are likely to crystallize.
According to Lebeddevs description,phenol is sulphonated with 98% sulphuric acid taken in the proportions of 400-500 parts of acid for 100 parts of phenol.The sulphonation temperature is maintained within 70-80.c or 100-110.c.The reaction time is 4hr.A temperature of 125-130 may also be maintained,in which case the reaction time can be reduced to 2 hr.Cast iron sulphonators are used,2 m in diameter and 1.8 high.The required temperature may be maintained in the sulphonator by heating with a steel heating coil or with a heating jacket.
If concentrated(98%)sulphuric acid has been used for the sulphonation,the sulphophenol should be diluted with water prior to nitration,otherwise the nitration reaction may proceed too violently.
The dilution of sulphophenol is effected in special stoneware vessels.for 95kg of sulphophenol 72 L of wash water is added.The specific gravity of the sulphophenol after dilution should be 1.35.The diluted sulphophenol is left to settle and then filtered through a sand filter.The temperature of the sulphophenol which is to be nitrated should not be lower than 50.c,which is necessary for initiating the nitration process.
shady mutha
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posted March 24, 2001 02:24 AM
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The second stage in the manufacture of picric acid is the nitration of the phenol-sulphonic acid(sulphophenol)obtained.The simplest reactors used for this process are stoneware jars,"tourills",which may be of various size(e.g.85cm diameter in the widest part,1.35m in height).The lids of the jars are equipped with two wide entry holes,15cm in diameter,one for feeding the nitrator with acid and sodium nitrate,the other for connecting the nitrator with the ventilating system.In addition to this,three smaller holes in the lid serve for introducing sulphophenol,inserting a compressed air line that reached down to the bottom of the jar and for inserting a thermometer.Naturally,various modifications of the nitrator construction are possible.These jar nitrators have the disadvantage of not being equipped with heating or cooling devices:the heat is supplied by the reaction itself and the required temperature is maintained by adjusting the flow of the reactants.
shady mutha
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posted March 24, 2001 02:13 PM
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To facilitate working and increase output the nitrators are transported in wooden carts from the nitration section to a separate place,where the nitrator contents are allowed to cool prior to their transport to the purification section,where picric acid is separated from the spent acid and washed with water.
Usually the nitrator is tightly enclosed in the cart by a cement layer.This is necessary to isolate and to prevent the nitrator from any damage.Should the jar-nitrator crack because of too high a temperature,the cement layer prevents the reaction mixture from flowing off;sometimes it can even be recovered.
In France nitration was effected in the following way(Pascal)
The jar-nitrator is charged with 275kg of 44% nitric acid or with the mixture:
nitric acid(44%)120kg
sodium nitrate 90kg
To this 180kg of warm 50-70.c sulphophenol(corresponding to 30kg of phenol)is gradually added.At the same time compressed air is passed through the nitrator to mix the reactants well.The rate of addition of sulphophenol should be so adjusted as to prevent the temperature from rising too rapidly at the beginning of the reaction.Hence the sulphophenol should be added carefully at first,although its flow must be rapid enough to attain a temperature of 100.c,at which the main portion of the product nitrates.If the process is operated properly,95-100.c is attained within 20 min from the beginning of the process(initial temperature 25-30.c)After one hour a temperature of 115-120 is attained.All the sulphophenol should be added within one and a quarter hours.By this time the temperature falls to 90-100.c.Then,to remove nitrogen oxides,air is blown through the nitrator for 10-20min and the nitrator is disconnected from the ventilating pipe and transported to the cooling section
shady mutha
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posted March 25, 2001 03:09 PM
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The nitrator contents are stirred repeatedly with a wooden pole while cooling to prevent picric acid from forming lumps which might retain impurities.After cooling for3-4 hr at a temperature of about 60.c,50-100 L. of water is added,thus preventing the precipitation of sodium bisulphate or,if it has already been precipitated,causing it to go into solution.The diluted acid contains some 45% of H2SO4,the concentration at which the solubility of picric acid is lowest.After it has cooled to ambient temperature 12-24 hr,the spent acid is drawn off by a siphon and the picric acid is transported to another section,where it is washed with water.Since the spent acid usually does not contain more than 1% of HNO3,its recovery is pointless.
The contents of 4-5 nitrators(200-300kg of picric acid)are transferred by means of wooden ladles to a wooden washing vat,where picric acid is washed several(mostly five)times with 150-200L.portions of water.For 100kg of picric acid 400L. of water is used.The product is tested for purity by determining the SO42+ ions in a solution of the picric acid in distilled water.After washing picric acid is separed from water in a centrifuge usually made of copper,the water content being brought to 5-7%.
Washings are collected in special wooden tanks for settling.The spent acid is also added to the washings so as to bring the H2SO4 content to 10-30% as in such "acid water"the solubility of picric acid is at its lowest.The water is decanted from time to time and disposed off into the river,after being neutralized,while the settled picric acid is collected from the botton of the tank.
The recovered picric acid usually contains large quanities of mineral matter(determined as ash-0.2%,compared with the permissible limit of 0.03%,as well as H2SO4(0.1 instead of 0.02%)Such a product cannot be used for military purposes without further purification by crystallization from water.
shady mutha
Frequent Poster
Posts: 149
From: australia
Registered: SEP 2000
posted March 25, 2001 04:36 PM
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United States method
During World War I a method of manufacture of picric acid was established in the United States.
Olsen and Goldstein described the method as follows.
302.2kg of phenol are sulphonated with 605 kg 93%sulphuric acid at 95-98.c during 6 hr.The product is composed of 80% phenol-4-sulphonic acid and 20% phenol-2-4-disulphonic acid.
The mixture of phenolsulphonic acids is diluted with 737.5 L. of water.Usually wash-waters are used for this purpose.The concentration of phenolsulphonic acid in the resulting solution is 18.4 calculated on phenol.
nitration is carried out in two stages.In the first stage the nitrator is filled with a nitrating mixture composed of 70% HNO3,10%H2SO4 and 20%H20.The quanity of the mixture corresponds to that calculated for the indroduction of one nitro group.Phenolsulphonic acid is added to the nitrating mixture at 30.c at the beginning and 52.c at the end.During the first stage mononitro derivatives are formed.
After the first stage the temperature in the nitrator is raised to 60.c and the second stage begins.It consists in adding the same nitrating mixture.During the first hour of mixing the temperature increases to 110-115.c.Altogether 1250 kg of nitrating mixture are added(i.e. 2.75 kg of HNO3 for 1 kg of phenol.)
This method is not accompanied by the evolution of large quanity of nitrogen oxides.The nitration is ended when the content of the nitrator changes colour from red(the colour of phenolsulphonic acids)to yellow(the colour of picric acid)
The yield is 667.6 kg of picric acid,i.e. 220% by weight(theoretical yield 243%)
The spent acid contains 1.0 and 1.5% of picric and oxalic acis respectivly.
It is diluted with double its weight of water;water from washing picric acid is beingused.The solution is brought to bioling for 5 hour to transform the remaining nitro-phenolsulphonic acids into picric acid.After cooling,a second crop of picric acis is obtained in quanity 15% by weight of phenol,i.e the total yield is 235% by weight.The losses of picric in the wash waters correspond to 1% of phenol.
shady mutha
Frequent Poster
Posts: 149
From: australia
Registered: SEP 2000
posted March 25, 2001 07:42 PM
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The construction of picric acid driers presents certain difficulties because of the ready formation of picrates.Having this in mind,wood is mostly used as the construction material for driers,and any metal parts(screws nails)should be made either of metals that form picrates with difficulty such as copper or alumimium,or of tinned metals or stainless steel.
Literature:
M.Marqueyrol and P.Loriette,Bull.soc.chim.France 25,371(1919)27,420(1920)
P.Pascal,Poudres,explosifs,gaz de combat,Hermann,Paris,1925
R.King,J.Chem.soc.119,2105(1921)
H.Arundal,G.P Davies ans I.C.I.Ltd,Brit.Pat 370436(1931)
I.V.Lebedev,Proizvodstwo pikrinovoi kisloty,Goskhimtekhizdat,Moskva-Leningrad,1934.
F.Olsen and J Goldstein,Ind.Eng.chem.16,66(1924)
H.s.Reed,Ind.Eng.Chem.16,72(1924)
Technical Records of Explosives Supply 1924-1918,No 6.Manufacture of picric acid,HMSO,London,1921.
R.Wolffenstein and O.Boters,Ger.Pat 194883(1906);Ber.46,586(1913)