CN104045569A

CN104045569A - Process for synthesis of toluenediamine by low pressure hydrogenation of dinitrotoluene, catalyst and preparation method of catalyst

Info

Publication number: CN104045569A
Application number: CN201410203541.4A
Authority: CN
Inventors: 范辉; 李改英; 王月玲
Original assignee: Sedin Engineering Co Ltd
Current assignee: Sedin Engineering Co Ltd
Priority date: 2014-05-15
Filing date: 2014-05-15
Publication date: 2014-09-17
Anticipated expiration: 2034-05-15
Also published as: CN104045569B

Abstract

A process for synthesis of toluenediamine (TDA) by low pressure hydrogenation of dinitrotoluene (DNT) is as follows: preparing a fresh Raney nickel catalyst and DNT into fresh catalyst slurry, adding the fresh catalyst slurry into a hydrogenation reactor; respectively adding raw material DNT and hydrogen into the hydrogenation reactor for reaction, leading a liquid reaction product into a catalyst separator I for separation, sending an upper clear liquid to a catalyst separator II, sending a gas phase into a purge gas separator, and returning settled catalyst slurry to the hydrogenation reactor; and filtering a clear liquid in the central part of the catalyst separator II with a filter to obtain a crude TDA product. The process has the advantages of low equipment investment, low energy consumption, and synthesis of the toluenediamine (TDA) by hydrogenation of the dinitrotoluene in the absence of an externally added solvent and under the low pressure condition of 1MPa.

Description

By the synthetic technique of tolylene diamine of dinitrotoluene (DNT) low-voltage hydrogenation and the method for making of catalyzer and catalyzer

Technical field

The invention belongs to the synthetic technique of tolylene diamine of a kind of work and the preparation method of catalyzer and catalyzer, relate in particular to technique by the synthetic tolylene diamine of dinitrotoluene (DNT) low-voltage hydrogenation and the preparation method of the Raney's nickel catalyst that uses and catalyzer.

Background technology

Tolylene diamine (TDA) has another name called diaminotoluene, is a kind of important industrial chemicals and chemical intermediate, conventionally adopts dinitrotoluene (DNT) (DNT) to add outside hydrogenation under organic solvent and catalyzer existence and synthesizes.The current industrial two kinds of DNT hydrogen addition technologies that mainly contain: the first is the Dupont technology that adopts loading type Pd+Pt/C noble metal catalyst, there is reaction pressure low (1MPa), catalyst activity is high and reaction without plus solvent, but exist catalyzer difficult separated, expensive and be easy to carbon distribution or shortcoming poisoning and inactivation; Another kind is to adopt the German BASF technology that Raney-Ni is catalyzer, this technology has the cheap and separated simple advantage of catalyzer, but it exists, reaction pressure high (2MPa), facility investment are large, flimsy shortcoming is held in the sealing of reactor whipping appts.Above-mentioned two kinds of DNT hydrogenation techniques and catalyst preparation technology are all subject to the blockade of foreign technology simultaneously, and the one-tenth that has greatly increased domestic TDA produces cost, has reduced the competitive power with external TDA giant.Therefore, develop a kind of cheap, reaction conditions is gentle, reaction has important practical significance without outer solvent and novel DNT hydrogenation technique and the catalyzer with domestic independent intellectual property right.

Open the improving hydrogenation of dinitro toluene of patent CN1245163A, integer catalyzer is applied in the reaction of the synthetic tolylene diamine of hydrogenation of dinitro toluene, by dinitrotoluene (DNT) is contacted and is reacted with hydrogen in the reactor of integer catalyzer that is filled with high gap volume with hydrogen, its catalyzer is 1% palladium of 200 cavitys per square inch and the silica dioxide coating of 11% nickel, and the hydrogenation of dinitro toluene speed under 130 ℃ and 1.6MPa condition is greater than 2 grams of moles of DNT/ rice ³catalyzer second, this invention has adopted integer catalyzer, avoided the recovery of solid catalyst in reaction liquid phase, but its temperature of reaction and reaction pressure are still higher, and reaction still needs to use plus solvent.

Patent CN101687767A discloses a kind of system and method for the production of aniline and tolylene diamine, it is characterized in that by high-shear device, the hydrogen gas bubbles in reaction being crushed to below one micron, greatly improved the rate of mass transfer of reaction, its hydrogenation reaction rate is not experience 5 times of high shear mixing described in patent.Patent CN102272092A discloses a kind of method of preparing tolylene diamine under the existence of suspended catalyst by hydrogen hydrogenation dinitrotoluene (DNT), by having increased in reactor head, advance central tubular stinger garrulous and that longitudinally install along reactor, changed the flow direction of reaction mass in reactor, increased the heat exchange efficiency of the interchanger of inside reactor, the external heat exchanger of simultaneously setting up further reclaims the heat of reaction product, finally produced the water vapour that is not less than 0.4MPa, utilized more fully hydrogenation reaction heat, but for achieving the above object, the temperature of reaction of this invention is more than 180 ℃.

Foregoing invention is mainly by structure of reactor, catalyst loading retrofit scheme and heat exchange mode are changed, and object is to reach the object that improves production capacity and reduce energy consumption.But foregoing invention does not fundamentally solve two kinds of industrial DNT hydrogen addition technologies as Sweden, the reaction that the catalyzer that exists in Dupont technology is expensive, exist in the easy inactivation of catalyzer and separation difficulty and BASF technology needs plus solvent, reaction pressure is high and facility investment is large problem.

Summary of the invention

One of object of the present invention is to provide that a kind of facility investment is few, and energy consumption is low, and under without plus solvent and 1MPa low pressure condition the continuous production processes of the synthetic tolylene diamine of dinitrobenzene hydrogenation.

Two of object of the present invention is to provide a kind of cheap, has nickel-base catalyst and the preparation method of the synthetic tolylene diamine performance of good catalysis hydrogenation of dinitro toluene.

For reaching above-mentioned purpose, the present invention breaks through nickel-base catalyst needs plus solvent and reaction pressure up to the chains of this routine techniques cognition of 2MPa in hydrogenation of dinitro toluene reaction, analysis by a large amount of catalyst modification experiments, active appraisal experiment and mechanism is screened relatively various nickel-base catalysts, and successfully develop a kind of low pressure 1MPa left and right with without plus solvent condition under there is the Raney's nickel catalyst to the similar activity of noble metal catalyst; And according to catalytic performance, intensity and the settling property of the Raney's nickel catalyst of exploitation, by a large amount of Theoretical Calculation and experimental study, further develop the novel process that a kind of hydrogenation of dinitro toluene is produced tolylene diamine continuously; The invention of the novel process of Raney's nickel catalyst in hydrogenation of dinitro toluene has not only overcome the shortcoming of existing two industrial DNT hydrogen addition technologies completely, fundamentally solved two kinds of industrial hydrogenation of dinitro toluene technology as Sweden, the reaction that the catalyzer that exists in Dupont technology is expensive, exist in the easy inactivation of catalyzer and separation difficulty and BASF technology needs plus solvent, reaction pressure is high and facility investment is large problem.And greatly reduce industrial cost and energy consumption, there are larger industrialization potentiality.

A kind of Raney's nickel of the present invention, for the technique of the synthetic tolylene diamine of dinitrotoluene (DNT) low-voltage hydrogenation, specifically comprises the steps:

(1) fresh Raney's nickel catalyst and DNT are configured to live catalyst slip in live catalyst storage tank, and are added in hydrogenation reactor; Raw material DNT and hydrogen add in hydrogenation reactor and react respectively, and reaction heat shifts out by the coil pipe of hydrogenation reactor and the water coolant in chuck; The liquid product of reaction imports catalyst separator I from hydrogenation reactor bottom, and carries out pressure equilibrium by pipeline and catalyst separator I;

(2) from the liquid product of hydrogenation reactor after catalyst separator I separation, upper clear supernate is delivered in agent separator II, gas phase from catalyst separator I top enters the separator of exitting of speeding, and the catalyst slurry of sedimentation is back to hydrogenation reactor from catalyst separator I bottom; The speeding in separator of speeding to exit exit emptying or recycling, in the separator of speeding to exit, isolated liquid phase is back in hydrogenation reactor;

(3) after being filtered from the clear liquid at catalyst separator II middle part thick TDA product; It is one standby that strainer one leaves, the lower small catalyst particles elder generation of strainer filter by high pressure nitrogen blowback to spent catalyst storage tank, then by coming de-salted water regularly strainer to be cleaned, spent catalyst slip after cleaning is delivered to spent catalyst storage tank, from gas phase emptying or the recycling at catalyst separator II top, and the catalyst slurry of sedimentation is back to hydrogenation reactor from catalyst separator I bottom.

Raney's nickel catalyst as above, is characterized by catalyst quality and consists of Ni85～90wt%, Al5～10wt%, and promoter metal 2～7wt%, promoter metal is one or more in Fe, Cr and Mo.

The preparation method of Raney's nickel catalyst as above comprises the steps:

By granularity, be that 2～6 μ m nickel powders, 5～15 μ m Al powder and 4～8 μ m promoter metal powder be take massfraction as Ni40wt%～55wt%, Al40wt%～55wt%, promoter metal 1wt%～5wt% mixes, then by microwave, with the speed of 30～80 ℃/min, be heated to 1400～1600 ℃ of meltings, through the Ar of 0.8～1.0MPa carry out gas atomization after cooling alloy powder, rate of cooling is 1.0～1.5 * 10 ⁶k/s; Mass ratio by alloy powder and NaOH powder with 1～1.5:1 mixes, and at normal temperatures the distilled water of 3～5 times of alloy powder volumes is dropped in container, and rate of addition keeps mix wetting evenly but do not form liquid phase; Suspension liquid after dropping is finished is at 20～80kHZ, and ultrasonic 20～40min under the condition of 40～70 ℃ then obtains 150～300 object catalyzer after distilled water wash, is kept in water standby.

The object of this invention is to provide a kind of cheap, and under without plus solvent and 1MPa low pressure condition, there is the nickel-base catalyst of good catalysis hydrogenation of dinitro toluene performance, and further develop a kind of facility investment and lack and the low tolylene diamine continuous production processes of energy consumption.For reaching above-mentioned purpose, the nickel-base catalyst of the present invention's exploitation must meet: under the low pressure condition of 1MPa left and right, catalyzer has the activity similar to noble metal catalyst, transformation efficiency >=99.8% of industrial requirements DNT; Catalyzer essential can be under the condition without plus solvent the carrying out of catalysis DNT hydrogenation reaction; Considering that hydrogenation of dinitro toluene reaction process carries out in liquid phase, is to guarantee the supplementary continuity of live catalyst, needs catalyzer without reduction or can reduce online; Consider that reaction needs mechanical stirring, therefore require catalyzer to there is higher physical strength; Consider that catalyzer needs and liquid phase separation, therefore require catalyzer to there is good settling property.

Be usually used in aromatic nitro compound Hydrogenation and comprise four kinds of loading type nickel-based catalyst, Uru shibara nickel catalyst, amorphous nickel alloy catalyst and Raney's nickels for the nickel-base catalyst of aromatic amino compound.By the preparation condition of above-mentioned four kinds of nickel-base catalysts is optimized, and further according to catalyst hydrogenation performance and character, it is screened, its preparation and appreciation condition refer to comparative example 1～4, and evaluation result sees attached list 1.From subordinate list 1, loading type (comparative example 1) catalyzer is under the condition of hydrogenation of dinitro toluene 2 and 1MPa, the equal difficulty of catalyst activity and selectivity reaches industrialized requirement, and the outside reduction of loading type nickel-based catalyst need, cannot realize the continuous supplementation of live catalyst, lacquer original nickel (comparative example 2) catalyzer shows good Hydrogenation when 2MPa, but its low-voltage hydrogenation poor-performing, and catalyst strength is poor, cause catalyzer very easily fragmentation and inactivation, be difficult to meet the requirement to the intensity of catalyzer of reaction system that band stirs, and Ni-B amorphous alloy (comparative example 3) catalyzer 2 and 1MPa condition under, all show good catalysis hydrogenation of dinitro toluene performance, but similar with Uru shibara nickel catalyst, the physical strength of this catalyzer is also poor, very easily fragmentation and inactivation, by load, can increase the intensity of catalyzer, but the Ni-B catalyst activity reduction after discovery load, this is due to after catalyst cupport, unit catalyst n i-B number of active center reduces relatively, therefore DNT transformation efficiency declines on the contrary when adding the catalyzer of equal in quality, simultaneously a little less than the effect due to Ni-B active ingredient and carrier, under agitation condition, active ingredient very easily comes off and inactivation from carrier surface, by ordinary method, the Raney-Ni catalyzer (comparative example 4) of industrial Ni-Al alloy powder activation preparation is shown to good Hydrogenation under 2MPa condition, when reaction pressure is down to 1MPa, catalyst activity slightly declines, but the selectivity of tolylene diamine is still 100%, during the life assessment of 200h, catalyst deactivation do not detected yet.Comparatively speaking, Raney's nickel catalyst is except low pressure activity is poor, and other all meets the requirement of the present invention to catalyzer, how to improve the low-voltage hydrogenation performance of Raney's nickel catalyst, becomes key of the present invention.

In the preparation process of alloy powder, thing phase composite in the involutory bronze of the degree of uniformity of the mass ratio of each metal, heat-up rate, temperature and speed of cooling, size of nickel crystallite, degree of uniformity and form have important impact, and then affect the nickel active centre activity in extracting rear catalyst, quantity, catalyst strength, specific surface area and the Catalytic Hydrogenation Properties in nickel active centre.In conventional method alloy smelting process, because heat is realized by thermal radiation or thermal conduction, therefore there is obvious thermograde, very easily cause crystalline phase inhomogeneous, simultaneously because heat-up rate is extremely slow, the alloy phase fusion time is long, makes alloy grain growth too fast, thereby affects the Hydrogenation of subsequent catalyst.Microwave technology has advantages of homogeneous heating, heat-up rate is fast and energy-conservation, and when microwave irradiation is during to surface, reguline metal, most of energy is reflected, can not be for heating; But when the geometrical dimension of metal is reduced to micron order, specific conductivity reduces rapidly, metal-powder can raise rapidly temperature by the microwave absorbing for heating, and then can be by microwave for the smelting of metal sintering, metallic ore and synthesizing of multicomponent alloy.The present invention is the preparation process for Ni-Al Nickel Aluminium Alloy Powder by microwave technology, the advantage of preparing Ni-Al alloy phase ratio with conventional heating mainly contains: (1) is used microwave metallurgical because heat-up rate is very fast, can suppress growing up of Ni-Al grain structure, in the alloy that makes to prepare, the crystal grain of a component is thinner; (2) time that microwave method is prepared Ni-Al alloy shortens greatly, and energy consumption is compared with conventional heating energy-conservation 70～90%; (3) microwave belongs to body heat phase, and thermograde is less, therefore make the crystalline phase of Ni-Al alloy of preparation more even.

In the process of microwave sintering metal powder preparation Ni-Al alloy, the microwave absorbing property of each metal-powder and the temperature distribution in sample are to need the factor of consideration emphatically.Its difference due to its specific conductivity, impedance and granularity of different metal powder, there is obvious difference in its microwave absorbing property.Microwave conductivity rate and impedance are the inherent naturies of metal, therefore powder size is the main controllable factor that affects microwave absorbing property, the coupling of the less metallic particles of granularity and microwave is better, and the performance that metal-powder absorbs microwave is better.The present invention is respectively to pure Ni powder, the metal-powder of aluminium powder and auxiliary agent carries out microwave radiation elevated temperature test, find as Ni particle diameter >=6 μ m, Al particle diameter >=15 μ m, during the μ m of promoter metal particle diameter >=8, each metal-powder is under the microwave radiation of 0～600 ℃, heat-up rate is lower than 30 ℃/min, preparation time is long, cause crystal grain to become large, along with reducing of metal-powder particle diameter, the heat-up rate of metal-powder increases gradually, as Ni particle diameter≤2 μ m, Al particle diameter≤5 μ m, during the μ m of promoter metal particle diameter≤4, heat-up rate reaches 80 ℃/min, but metal-powder is meticulous, can increase its preparation cost, cause catalyzer investment to increase, therefore it is 2～6 μ m nickel powders that alloy powder of the present invention adopts granularity, 5～15 μ m Al powder and the preparation of 4～8 μ m auxiliary agents, its heat-up rate is 30 ℃/min～80 ℃/min.

In the preparation process of alloy powder, the proportioning of raw material has determined the thing phase composite in alloy powder, and finally the structure of catalyzer and performance is had to important impact.In alloy powder finished product, mainly contain Al/NiAl ₃, NiAl ₃, Ni ₂al ₃with NiAl tetra-kinds of crystalline phases, wherein Al/NiAl ₃and NiAl ₃in very easily extracting of aluminium, and after extracting, form the structure with macropore, even monocrystalline, can provide for catalyzer the active centre of some amount, but catalyst strength is poor; Ni ₂al ₃aluminium in alloy phase is carried compared with hard-pumped, but extracting complete after formation there is in a large number the polycrystalline nickel active centre of lattice dislocation, there is the thin feature in Duo He aperture, duct, therefore its intensity is high, be catalyzer provider skeleton structure; Aluminium in NiAl is difficult to extracting, and active centre is not provided substantially, is only to play the effect that improves catalyst strength and stability in finished catalyst.Under the smelting mode and preparation parameter condition of preparing at above-mentioned alloy powder disclosed by the invention, and find in conjunction with Ni-Al phasor and lot of experiments, when Ni powder mass content is lower than 40wt%, and Al powder content is greater than 55wt%, is mainly Al/NiAl in alloy powder ₃and NiAl ₃alloy phase, the intensity of the catalyzer of preparation is lower, and catalyzer very easily fragmentation or nickel active centre runs off and inactivation, and when nickel powder content is higher than 55wt%, and Al powder content is during lower than 40wt%, in the catalyzer of preparation, is mainly Ni ₂al ₃with NiAl crystalline phase, although catalyst strength is larger, aperture and specific surface area are less, and nickel number of active center is few, and catalyst activity is low, therefore work as Ni40wt%～55wt% in alloy powder, during Al40wt%～55wt%, in the alloy of preparation, main thing is NiAl mutually ₃and Ni ₂al ₃thing phase, the catalyzer after extracting is not only active high, and catalyzer has advantages of that intensity is high and specific surface area is large.

What smelting temperature formed alumel has a great impact, the present invention prepares Ni-Al alloy powder by microwave powder smelting and spray method, therefore require metal-powder to reach molten state completely when determining smelting temperature, guarantee that alloy melt does not solidify plug nozzle in the process that imports spray chamber by microwave oven, when smelting temperature is during lower than 1400 ℃, melt very easily goes out frozen plug duct at atomizing nozzle, when smelting temperature is during higher than 1600 ℃, not only power consumption is serious, and easily make the alloy grain of melting grow up, be unfavorable for catalyst activity, therefore smelting temperature disclosed by the invention is 1400 ℃～1600 ℃.

After melting, in the involutory bronze of the speed of cooling of alloy, crystalline phase forms and form also has important impact.Be usually used in alloy cooling have naturally cooling and a water Quench method, the present invention adopts atomization cooling, compare with first two technology, alloy globulate prepared by the present invention, and speed of cooling is faster, Ar in atomization process is weak reducing gas, in the preparation process of alloy powder, play two effects, the metal-powder that the first is melting provides protection, avoid in atomization process by oxygen reduction, another one effect provides atomizing pressure, the alloy of melting is cooling in spray chamber atomization by nozzle under the pressure of Ar, when Ar pressure is during lower than 0.8MPa, atomized molten alloy degree is lower, the granularity of alloy powder is larger, and speed of cooling is slower, when Ar pressure is during higher than 1.0MPa, alloy powder is meticulous, cause the catalyst particle size after extracting too small, be unfavorable for the separation of catalyzer, therefore the pressure of Ar gas is 0.8MPa～1.0MPa.

The Al extractive process of Ni-Al alloy is the process of the Al in alloy of removing with alkaline solution.Conventional Al extractive process be generally by NaOH solution be added in Ni-Al alloy powder stir and certain temperature under carry out Al extractive reaction, or alloy powder is added in batches and in NaOH solution, carries out Al extracting.The present invention adopts the separated leaching method of solid phase, be specially in the solid mixture of NaOH and alloy powder and dropwise add distilled water, it is evenly soaked and do not form liquid phase, after distilled water drips and finishes, the suspension slip of formation is placed in to ultrasonic wave, under stirring and certain temperature, carries out ultrasonic rear end.The activation method of alloy powder disclosed by the invention, has nickel crystallite little, the advantage that thermostability and toxin immunity are good.In the process of the separated leaching method of solid phase extracting Al, choosing of each preparation parameter has important impact to the composition of final catalyzer: when the mass ratio of NaOH and alloy powder is during lower than 1:1, alkali number deficiency causes a large amount of white mass NaAlO ₄generate and stop up duct, greatly reduce specific surface area and the activity of catalyzer, but when the quality of NaOH and alloy powder is during higher than 1.5:1, cause aluminium in catalyzer by ultra stripped, cause residual Al to promote the effect of nickel active centre and rugged catalyst structure to disappear, catalyst activity and stability all decline, therefore get the mass ratio of sodium hydroxide and alloy powder, are 1～1.5:1; Owing to being attended by Al (OH) in extractive process ₃generation with a large amount of hydrogen, and Raney's nickel specific surface increases gradually, therefore when the volume ratio of the distilled water adding and Nickel Aluminium Alloy Powder is during lower than 3:1, water shortage is to soak alloy mixture, when the volume ratio of the distilled water adding and Nickel Aluminium Alloy Powder is during higher than 5:1, cause forming solution, the generation of hydrogen easily causes the generation of a large amount of foams, therefore amount of water is 3～5:1 with Ni/Al alloy powder volume ratio.

The present invention is adopting microwave powder metallurgy legal system for alloy powder precursor, the alloy powder of preparation has than the less more uniform crystal grain of ordinary method, by solid phase leaching separation method, undertaken after aluminium extracting, the duct forming is less and more even, but consider the feature of whole leaching separation process, make the aluminium extracting hydrate generating very easily stop up duct.Therefore the present invention is placed in ultrasonic wave by the suspension of preparation, at a certain temperature with agitation condition under carry out ultrasonic, its objective is catalyst surface and body inner oxide and impurity removing, and add the extracting speed of aluminium in fast channel, further increased the specific surface area of catalyzer.In ultrasonic procedure, hyperacoustic frequency is extremely important, when hyperacoustic frequency is during lower than 20kHZ, ultrasonic wave does not have the gas core in suspension liquid of the present invention is produced to cavity effect, do not reach the object of cleaning, when hyperacoustic frequency is during higher than 80kHZ, most energy can be converted into heat energy, cause the waste of energy, therefore the ultrasonic frequency adopting is 20～80kHZ.In carrying out the process of aluminium extracting, the residual volume of extracting time and temperature major effect aluminium extracting speed and aluminium, and the effect that residual Al not only can play refinement nickel crystallite and improve number of active center, and certain aluminium content contributes to the stable of catalyst structure and performance, when activation temperature is lower than 40 ℃, ultrasonic time is during lower than 20 minutes, aluminium extracting speed is slower, in the catalyzer that causes finally preparing, residual Al is too much, the nickel number of active center and the specific surface area that form are less, affect the performance of catalyzer, when activation temperature is higher than 70 ℃, when ultrasonic time is greater than 40min, can cause again aluminium extracting too much, and then cause catalyzer easily broken, its activity and stability decline on the contrary, therefore the present invention is openly under 40～70 ℃ of conditions, after ultrasonic 20～40min, and must catalyzer after washing.

The condition of hydrogenation of the present invention is that temperature of reaction is 95～115 ℃, and reaction pressure is 0.9～1.1MPa, and the mol ratio of hydrogen feed and DNT charging is 6.0～6.5, and stirring velocity is 350～500 revs/min.

Definite association reaction feature and catalyst performance of needing of reaction conditions considers.When temperature of reaction is during lower than 95 ℃, reaction is subject to kinetic control, and the hydrogenation speed of dinitrotoluene (DNT) is slower, affects the production capacity of tolylene diamine, when temperature of reaction is during higher than 115 ℃, because dinitrotoluene (DNT) is a strong exothermal reaction, not only make reaction be subject to the impact of thermodynamic(al)equilibrium, cause DNT residual volume in product to improve, and can cause that dinitrotoluene (DNT) deep hydrogenation generates the byproducts such as tar, even can make catalyst deactivation at catalyst surface carbon distribution, therefore selective reaction temperature is 95～115 ℃; Hydrogenation of dinitro toluene reaction is the reaction of a volume-diminished, when reaction pressure is during lower than 0.9MPa, raney ni catalysis hydrogenation reaction Speed Reduction, cause the raising of DNT residual volume in the reduction of production capacity and product, when reaction pressure is during higher than 1.1MPa, the not only investment of augmenting response device, and cause the easy carbon distribution of catalyst surface, affecting catalyst life, is 0.9MPa～1.1MPa therefore choose reaction pressure; In hydrogenation of dinitro toluene reaction, hydrogen feed is 6.0 with the theoretical molar ratio of DNT charging, when this ratio is less than 6, cause the DNT can not complete reaction, when this ratio is greater than 6.5, excessive hydrogen can cause the further hydrogenation of product, cause the generation of by product, and excess hydrogen needs partitioning cycle, increase energy consumption, therefore determine that the mol ratio of hydrogen feed and DNT charging is 6.0～6.5; In gas-liquid-solid phase reaction, stirring velocity has larger impact to the mass transfer in reaction system and heat transfer, in the hydrogenation reaction of dinitrotoluene (DNT), when stirring velocity is during lower than 350 revs/min, dinitrotoluene (DNT) and hydrogen are slower in rate of mass transfer and the heat transfer of liquid phase, and be difficult to play the object to hydrogen gas bubbles fragmentation, affect shifting out of speed of reaction and reaction heat, when stirring velocity is during higher than 500 revs/min, the serious wear of stirring rake to catalyzer, cause catalyst life to reduce, therefore stirring velocity is 350～500 revs/min.

The mean residence time of DNT raw material in hydrogenation reactor is 2.5～3.5h as mentioned above.

In the production of the synthetic tolylene diamine of industrial hydrogenation of dinitro toluene, require the transformation efficiency of DNT to reach more than 99.98%, and the height of the transformation efficiency of dinitrotoluene (DNT) is except being subject to the impact of reaction conditions and catalyst activity, the reaction times is that the retention time of raw material in reactor is also important factor.Raw material DNT in reactor retention time determine factors such as wanting in combined catalyst hydrogenation speed and reactor mass-transfer efficiency.

For determining more accurately the reaction times of catalyzer, we further study the speed of reaction of the reaction mechanism of DNT hydrogenation and Raney-Ni catalyzer, and concrete determination step is shown in comparative example 5～6, the results are shown in accompanying drawing 1～3.From accompanying drawing 1, in hydrogenation of dinitro toluene reaction process, hydrogenation of dinitro toluene is divided into two kinds of routes: first the nitro in (1) dinitrotoluene (DNT) generates azanol base intermediate phase with hydrogen reaction, and azanol base intermediate phase again hydrogenation generates tolylene diamine; (2) in dinitrotoluene (DNT) nitro first hydrogenation generate aminoly, then an other nitro hydrogenation generates tolylene diamine.

Raney-Ni catalyzer and (the Pd+Pt)/C speed of reaction figure of accompanying drawing 2 and 3 for carrying out on 500ml small testing device.As seen from the figure, at the 0-15min of the reaction of DNT hydrogenation in the reaction times, mainly there is DNT to the process of intermediate product conversion in two catalyzer, the catalyst based catalytic rate to this process of Ni is starkly lower than Pd/C noble metal catalyst, along with the prolongation in reaction times, two catalyzer all show higher hydrogenation speed, when the reaction times is 35min, TDA concentration in Ni catalyst reaction system reaches 90%, and Pd+Pt noble metal catalyst only just makes the concentration of TDA reach 90% in 30min left and right; Along with the reaction times continues to extend, raw material DNT is all converted into TDA product or intermediate product, therefore the main generation intermediate product in this stage is to the transformation of TDA product, because this stage approaches molecular balance more, therefore the catalytic hydrogenation reaction speed of two catalyzer is all lower, but Ni is catalyst based, show the activity higher than precious metal, the former only just completes residue intermediate product to the conversion of TDA product with 20min, and noble metal catalyst 30min consuming time just completes residue reaction, cause the total consuming time than the few 5min of noble metal catalyst of Ni catalyst DNT hydrogenation reaction.Visible, the W-response speed of Raney-Ni catalyzer is a little more than noble metal catalyst, reaction times is that 55min has just reacted, but above-mentioned experiment is carried out under comparatively ideal lab scale state, when Industrial processes, due to tens times of reactor popularizations hundred times even, Mass Transfer Model in reactor is more complicated, average these data of retention time can not adopt the test result of lab scale completely, therefore the present invention further adopts Fluent software to simulate the fluid in reactor, and adopts 50m ³reactor carried out the cold-flow model experiment of mass transfer, be found to be and make DNT transformation efficiency reach industrial requirement, raw material DNT is at technical grade hydrogenation reactor (50m ³) retention time 2.5～3.5 times of left and right that are desirable retention time, in conjunction with the experience of TDI industrial design for many years, being averaged retention time is 2.5～3.5h.

The present invention, in the start-up of reaction, makees solvent with pure water in hydrogenation reactor, and after device is stable, the liquid phase of reactor outlet consists of: H ₂o36.5～37.5wt%, TDA58.5～59.5wt%, catalyzer 3～5wt%.

DNT is hydrogenated to strong exothermal reaction, for avoiding the problems such as temperature runaway that reaction heat causes and sintering of catalyst, need make reaction carry out under solution state, and the present invention adopts reaction product as solvent.In start-up, if reacted with pure DNT, DNT viscosity is unfavorable for greatly diffusion and the absorption of hydrogen, and then impact reaction, can not directly pass into pure DNT; Consider that water is product, and fresh Raney-Ni catalyzer also needs water seal, thus in start-up, adopt water as solvent, and Raney-Ni catalyzer also shows better Hydrogenation in pure water solvent, and concrete determination step is shown in comparative example 7, result subordinate list 2.Take in the DNT hydrogenation reaction that water is solvent, the selectivity of TDA is 100%, but DNT obtains transformation efficiency slightly to decline, this is because the solubleness of DNT in water is less, is dispersed in water, with the form of drop under the normal reaction times, the transformation efficiency of DNT slightly declines, by extending the retention time of start-up, can meet industrialized requirement, therefore employing water is solvent.The TDA content in hydrogenation reactor in dinitrotoluene (DNT) reaction, when generating TDA, can produce the water of 4 molecules, therefore along with the carrying out reacting, can increase gradually, considers in live catalyst and contains certain water, therefore finally make TDA and H in hydrogenation reactor simultaneously ₂the mass ratio of O is 1.56～1.63.

In DNT hydrogenation reaction, catalyst content in hydrogenation reactor has material impact to the performance of hydrogenation reaction, when the content of catalyzer in reactor is during lower than 3wt%, catalytic hydrogenation reaction speed is slow, and along with the increase of catalyst content, speed of reaction is accelerated gradually, but when catalyst content is greater than 5wt%, because solid content in reaction solution is too high, reaction affects mass transfer and heat transfer, therefore catalyst reactor content is 3～5wt%.

Reaction liquid phase as above is 1.5～1.6h in the average retention time of catalyst separator I, and removing the supernatant liquor of catalyst separator II and catalyst slurry mass ratio that catalyst separator I returns to hydrogenation reactor is 2.2～2.5; Reaction liquid phase is 2.5～3.5h in the average retention time of catalyst separator II, and removing the clear liquid of strainer and catalyst slurry mass ratio that catalyst separator II returns to hydrogenation reactor is 3.5～4.5; The mass content of the catalyzer in live catalyst storage tank is 10wt%, and the continuously feeding speed of live catalyst slip is 0.25～0.5% of dinitrotoluene (DNT) input speed.

The Separation and Recovery of catalyzer is the difficult point of slurry reactor technique always, and separating device is selected and definite need of separation parameter consider the many factors such as catalyst property, liquid viscosity and flow rate of liquid.Accompanying drawing 4 is the standing sedimentation experimental datas of 150～300 object Raney's nickel catalysts after stirring 20 days.As seen from the figure, Raney-Ni catalyzer shows good settling property in reaction liquid phase, and in 40min, the catalyst quality of sedimentation accounts for the 99.96wt% of total catalyst content, and the catalyst particle size of sedimentation is at 11.5～106 μ m.Paste state bed reactor catalyst abrasion inactivation is the major cause that causes catalyst deactivation, we have further carried out activity rating to the catalyzer of the different degrees of wear, research is found when the granularity of catalyzer wears up to 10 μ m left and right, degradation to 70% left and right of catalyzer, still think when catalyzer catalyst deactivation during lower than 10 μ m.

The present invention adopts secondary settlement separate, and according to above-mentioned standing sedimentation testing data, in catalyst separating tank I, the catalyzer of sedimentation accounts for 55～60wt% of catalyzer total amount, and catalyst grain size is between 80～104 μ m; And the main separate object of catalyst separating tank II is the catalyzer of 10～80 μ m, its content accounts for 40～45wt% of total content, and the catalyzer that is less than 10 μ m of remaining 0～0.5wt% enters spent catalyst storage tank after plate filter filters.Further by fluent, simulate and cold-flow model experiment, finally determine that the retention time of separating tank I is 1.5～1.6h, the average retention time of separating tank II is 2.5～3.5h.And the reflux ratio data of each separating tank further in conjunction with material balance, have been determined.

The input speed of live catalyst according to the sideline test measurement result of 3000 tons/year of above-mentioned operational paths, through the sideline test result to different grain size catalyzer, the catalyst attrition of finding 50 tons of TDA products of production is between 20～35kg, TDA product consumption per ton is 0.4～0.7kg Raney's nickel catalyst, and be 1.49 known according to the ratio of the molecular weight of DNT and TDA, the waste of the Raney's nickel catalyst of 1.49 tons of hydrogenation of dinitro toluene of every catalysis is 0.4～0.7kg, for maintaining the stable of catalyst content in whole reactive system, the input speed of 10wt% live catalyst slip accounts between DNT charging 0.27～0.47%, consider the fluctuation problem in actual production process simultaneously, therefore get the input speed of live catalyst slip account for DNT inlet amount 0.25～0.50% between.

The present invention compared with prior art has substantial feature and significant advantage is:

(1) the present invention is by screening experiment and the activity rating of a large amount of nickel-base catalysts, determined the research object of Raney's nickel catalyst as dinitrotoluene (DNT) low-voltage hydrogenation process, by microwave powder metallurgy technology and gas atomization technique, prepare Ni-Al alloy powder, then through solid phase pickling process and ultrasonic technique, carry out aluminium extracting and prepare final Raney's nickel catalyst.The preparation method of Raney's nickel catalyst disclosed by the invention has advantages of that preparation time is short, energy consumption is low, Ni crystal grain and pore passage structure is less more evenly, nickel number of active center increases, low pressure is active high.By simultaneous test (referring to embodiment 7 and comparative example 1～4), find, under without plus solvent, 110 ℃ and 1MPa low pressure condition, the selectivity of DNT transformation efficiency and TDA is 100%, and catalyst strength prepared by the present invention is high, catalyst stability is good, during the life assessment of 300h (input and output material is more than 1000 times), catalyzer is inactivation not, and its catalyzer over-all properties is obviously better than existing various nickel-base catalyst.Further by simultaneous test (referring to comparative example 6 and 7), find, Raney's nickel catalyst disclosed by the invention shows the Hydrogenation that is slightly better than noble metal catalyst in the hydrogenation of dinitro toluene reaction without plus solvent and low pressure 1MPa.

(2) performance, physico-chemical property and a large amount of experiment, software simulation and experience in design for many years of open Raney's nickel catalyst according to the present invention, further disclosed a kind of Raney's nickel catalyst is for dinitrotoluene (DNT) low-voltage hydrogenation process.Technique disclosed by the invention and Sweden, Dupont technology is compared, and catalyzer becomes cheap Raney-Ni catalyzer from precious metals pd+Pt/C catalyzer, and catalyzer cost reduces greatly; Because Raney-Ni catalyzer has good settling property and higher catalyst strength, therefore it adopts settlement separate equipment cheaply to replace expensive thickener, greatly reduce investment and the process cost of equipment.

(3) a kind of Raney's nickel catalyst disclosed by the invention is compared with BASF technology for the technique of dinitrotoluene (DNT) low-voltage hydrogenation, and reaction pressure is reduced to 1MPa by 2MPa, greatly reduces facility investment; Hydrogenation reaction is made solvent with product, has avoided plus solvent and the later separation facility investment and separated energy consumption that cause.

In sum, the present invention is by screening experiment and the activity rating of a large amount of nickel-base catalysts, successfully develop a kind of at 1MPa be issued to Raney's nickel catalyst and the preparation method of industrial requirement without plus solvent condition, and according to the feature of Raney's nickel catalyst, by lot of experiments, software simulation and experience in design for many years, further develop the technique of DNT hydrogenation, overcome the problem and the shortcoming that in existing two kinds of industrial technologies, exist, there is potential industrial prospect.

Accompanying drawing explanation:

Accompanying drawing 1Raney-Ni catalysis 2, the hydrogenation mechanism of 4-dinitrotoluene (DNT).

The speed of reaction of accompanying drawing 2Raney-Ni catalysis hydrogenation of dinitro toluene.

The speed of reaction of accompanying drawing 3Pd+Pt/C catalysis hydrogenation of dinitro toluene.

Accompanying drawing 4Raney-Ni catalyzer standing sedimentation testing data.

The process flow sheet of accompanying drawing 5 hydrogenation of dinitro toluene.

Subordinate list explanation

The Evaluation results of the different nickel-base catalysts of subordinate list 1 in hydrogenation of dinitro toluene reaction.

The catalyzer of the preparation of subordinate list 2 embodiment 1～6 take the Evaluation results of water under solvent condition.

The Evaluation results of subordinate list 3 embodiment 1～6 catalyzer.

Embodiment:

Embodiment 1

6 μ m nickel powders, 5 μ m aluminium powders and 8 μ m promoter metal Fe powder be take to massfraction to be mixed as Ni55wt%-Al40wt%-Fe5wt%, being placed on bottom has funnel and around inlays in the crucible of SiC, with microwave, with the speed of 80 ℃/min, be heated to 1600 ℃ of meltings, after the Ar of 0.8MPa gasifies atomization, obtain alloy powder, rate of cooling is 1.0 * 10 ⁶k/s; Mass ratio by alloy powder and NaOH powder with 1:1 mixes, and at normal temperatures the distilled water of 3 times of alloy powder volumes is dropped in container, and rate of addition keeps mix wetting evenly but do not form liquid phase; Suspension liquid after dropping is finished is at 20kHZ, and ultrasonic 40min under the condition of 70 ℃ then obtains catalyzer after distilled water wash, is kept in water standby.Catalyzer prepared by this embodiment is as follows for concrete technology route and the reaction conditions of hydrogenation of dinitro toluene:

A. the Raney-Ni catalyzer of preparation and DNT are configured to the live catalyst slip that catalyst quality content is 10wt% in live catalyst storage tank, and the speed with 6kg/h is added in hydrogenation reactor through pipeline 4; Raw material DNT and hydrogen are squeezed in hydrogenation reactor through pipeline 1 and 2 respectively, and at H ₂with the mol ratio of DNT charging be that 6:1, temperature of reaction are that 95 ℃, reaction pressure are that 1.1MPa, catalyst quality content are that 3wt% and stirring velocity are to carry out hydrogenation reaction under the condition of 350 revs/min, reaction heat shifts out by the coil pipe of hydrogenation reactor and the water coolant in chuck; DNT raw material is average stop after 2.5h in reactor, and liquid product imports catalyst separator I from hydrogenation reactor bottom through pipeline 5, and carries out pressure equilibrium by pipeline 8 with catalyst separator I.

B. from the liquid product of hydrogenation reactor after the average stop 1.5h in catalyst separator I, upper clear supernate is added in settlement separator II through pipeline 12, and sedimentation catalyst slurry is first back in hydrogenation reactor by pipeline 9,10 and 6 by pump, the catalyst slurry of returning to hydrogenation reactor is 2.2 with removing the mass ratio of the clear liquid of catalyst separator II; Gas phase enters through pipeline 13 separator of exitting of speeding from top; The venting of speeding of speeding to exit in separator is through pipeline 14 emptying or recycling, and isolated liquid phase is back in hydrogenation reactor through pipeline 7.

C. the supernatant liquor that autocatalysis agent separator I comes carries out secondary settlement in catalyst separator II, settling time is 2.5h, the catalyst slurry of sedimentation is first back in hydrogenation reactor by pipeline 15,11 and 6 by pump, and clear liquid obtains thick TDA product after being filtered, it is 3.5 that catalyst separator II removes the clear liquid of strainer and the mass ratio that returns to the catalyst slurry of hydrogenation reactor; It is one standby that strainer one leaves, the lower small catalyst particles elder generation of strainer filter by high pressure nitrogen through pipeline 18 blowbacks to spent catalyst storage tank, then by the de-salted water from pipeline 22, regularly it is cleaned, spent catalyst slip after cleaning is also delivered to spent catalyst storage tank through pipeline 18, in gas emptying or the recycling out of catalyst separator II top.

The quality that catalyzer prepared by the present embodiment is measured through ICP forms and granularity for details see attached table 3; Catalyst activity data are all measured on the industrial side line device of 3000 tons/year, and concrete technology is shown in accompanying drawing 4, and process portion operating parameters and product form for details see attached table 3.

Embodiment 2

5 μ m nickel powders, 7 μ m aluminium powders and 7 μ m promoter metal powder be take to massfraction to be mixed as Ni53wt%-Al43wt%-auxiliary agent 4wt%, being placed on bottom has funnel and around inlays in the crucible of SiC, with microwave, with the speed of 70 ℃/min, be heated to 1550 ℃ of meltings, after the Ar of 0.9MPa gasifies atomization, obtain alloy powder, rate of cooling is 1.2 * 10 ⁶k/s; Mass ratio by alloy powder and NaOH powder with 1.1:1 mixes, and at normal temperatures the distilled water of 4 times of alloy powder volumes is dropped in container, and rate of addition keeps mix wetting evenly but do not form liquid phase; Suspension liquid after dropping is finished is at 30kHZ, and ultrasonic 35min under the condition of 60 ℃ then obtains object catalyzer after distilled water wash, is kept in water standby.Catalyzer prepared by this embodiment is as follows for concrete technology route and the reaction conditions of hydrogenation of dinitro toluene:

A. the Raney-Ni catalyzer of preparation and DNT are configured to the live catalyst slip that catalyst quality content is 10wt% in live catalyst storage tank, and the speed with 7kg/h is added in hydrogenation reactor through pipeline 4; Raw material DNT and hydrogen are squeezed in hydrogenation reactor through pipeline 1 and 2 respectively, and at H ₂with the mol ratio of DNT charging be that 6.1:1, temperature of reaction are that 100 ℃, reaction pressure are that 1.0MPa, catalyst quality content are that 4wt% and stirring velocity are to carry out hydrogenation reaction under the condition of 400 revs/min, reaction heat shifts out by the coil pipe of hydrogenation reactor and the water coolant in chuck; DNT raw material is average stop after 3.0h in reactor, and liquid product imports catalyst separator I from hydrogenation reactor bottom through pipeline 5, and carries out pressure equilibrium by pipeline 8 with catalyst separator I.

B. from the liquid product of hydrogenation reactor after the average stop 1.6h in catalyst separator I, upper clear supernate is added in settlement separator II through pipeline 12, and sedimentation catalyst slurry is first back in hydrogenation reactor by pipeline 9,10 and 6 by pump, the catalyst slurry of returning to hydrogenation reactor is 2.3 with removing the mass ratio of the clear liquid of catalyst separator II; Gas phase enters through pipeline 13 separator of exitting of speeding from top; The venting of speeding of speeding to exit in separator is through pipeline 14 emptying or recycling, and isolated liquid phase is back in hydrogenation reactor through pipeline 7.

C. the clear liquid that autocatalysis agent separator I comes carries out secondary settlement in catalyst separator II, settling time is 3.0h, the catalyst slurry of sedimentation is first back in hydrogenation reactor by pipeline 15,11 and 6 by pump, and clear liquid obtains thick TDA product after being filtered, it is 4.0 that catalyst separator II removes the clear liquid of strainer and the mass ratio that returns to the catalyst slurry of hydrogenation reactor; It is one standby that strainer one leaves, the lower small catalyst particles elder generation of strainer filter by high pressure nitrogen through pipeline 18 blowbacks to spent catalyst storage tank, then by the de-salted water from pipeline 22, regularly it is cleaned, the spent catalyst slip after cleaning is also delivered to spent catalyst storage tank through pipeline 18.

Embodiment 3

4 μ m nickel powders, 9 μ m aluminium powders and 6 μ m promoter metal powder be take to massfraction to be mixed as Ni53wt%-Al45wt%-auxiliary agent 2wt%, being placed on bottom has funnel and around inlays in the crucible of SiC, with microwave, with the speed of 60 ℃/min, be heated to 1500 ℃ of meltings, after the Ar of 1.0MPa gasifies atomization, obtain alloy powder, rate of cooling is 1.3 * 10 ⁶k/s; Mass ratio by alloy powder and NaOH powder with 1:2 mixes, and at normal temperatures the distilled water of 5 times of alloy powder volumes is dropped in container, and rate of addition keeps mix wetting evenly but do not form liquid phase; Suspension liquid after dropping is finished is at 50kHZ, and ultrasonic 30min under the condition of 60 ℃ then obtains catalyzer after distilled water wash, is kept in water standby.Catalyzer prepared by this embodiment is as follows for concrete technology route and the reaction conditions of hydrogenation of dinitro toluene:

A. the Raney-Ni catalyzer of preparation and DNT are configured to the live catalyst slip that catalyst quality content is 10wt% in live catalyst storage tank, and the speed with 8kg/h is added in hydrogenation reactor through pipeline 4; Raw material DNT and hydrogen are squeezed in hydrogenation reactor through pipeline 1 and 2 respectively, and at H ₂with the mol ratio of DNT charging be that 6.2:1, temperature of reaction are that 105 ℃, reaction pressure are that 0.9MPa, catalyst quality content are that 4wt% and stirring velocity are to carry out hydrogenation reaction under the condition of 450 revs/min, reaction heat shifts out by the coil pipe of hydrogenation reactor and the water coolant in chuck; DNT raw material is average stop after 3.5h in reactor, and liquid product imports catalyst separator I from hydrogenation reactor bottom through pipeline 5, and carries out pressure equilibrium by pipeline 8 with catalyst separator I.

B. from the liquid product of hydrogenation reactor after the average stop 1.6h in catalyst separator I, upper clear supernate is added in settlement separator II through pipeline 12, and sedimentation catalyst slurry is first back in hydrogenation reactor by pipeline 9,10 and 6 by pump, the catalyst slurry of returning to hydrogenation reactor is 2.4 with removing the mass ratio of the clear liquid of catalyst separator II; Gas phase enters through pipeline 13 separator of exitting of speeding from top; The venting of speeding of speeding to exit in separator is through pipeline 14 emptying or recycling, and isolated liquid phase is back in hydrogenation reactor through pipeline 7.

C. the clear liquid that autocatalysis agent separator I comes carries out secondary settlement in catalyst separator II, settling time is 3.5h, the catalyst slurry of sedimentation is first back in hydrogenation reactor by pipeline 15,11 and 6 by pump, and clear liquid obtains thick TDA product after being filtered, it is 4.5 that catalyst separator II removes the clear liquid of strainer and the mass ratio that returns to the catalyst slurry of hydrogenation reactor; It is one standby that strainer one leaves, the lower small catalyst particles elder generation of strainer filter by high pressure nitrogen through pipeline 18 blowbacks to spent catalyst storage tank, then by the de-salted water from pipeline 22, regularly it is cleaned, the spent catalyst slip after cleaning is also delivered to spent catalyst storage tank through pipeline 18.

Embodiment 4

3 μ m nickel powders, 13 μ m aluminium powders and 5 μ m promoter metal powder be take to massfraction to be mixed as Ni50wt%-Al47wt%-auxiliary agent (Fe+Mo) 3wt%, being placed on bottom has funnel and around inlays in the crucible of SiC, with microwave, with the speed of 50 ℃/min, be heated to 1450 ℃ of meltings, after the Ar of 0.9MPa gasifies atomization, obtain alloy powder, rate of cooling is 1.4 * 10 ⁶k/s; Mass ratio by alloy powder and NaOH powder with 1.3:1 mixes, and at normal temperatures the distilled water of 4 times of alloy powder volumes is dropped in container, and rate of addition keeps mix wetting evenly but do not form liquid phase; Suspension liquid after dropping is finished is at 50kHZ, and ultrasonic 25min under the condition of 50 ℃ then obtains catalyzer after distilled water wash, is kept in water standby.Catalyzer prepared by this embodiment is as follows for concrete technology route and the reaction conditions of hydrogenation of dinitro toluene:

A. the Raney-Ni catalyzer of preparation and DNT are configured to the live catalyst slip that catalyst quality content is 10wt% in live catalyst storage tank, and the speed with 9kg/h is added in hydrogenation reactor through pipeline 4; Raw material DNT and hydrogen are squeezed in hydrogenation reactor through pipeline 1 and 2 respectively, and at H ₂with the mol ratio of DNT charging be that 6.3:1, temperature of reaction are that 110 ℃, reaction pressure are that 1.0MPa, catalyst quality content are that 5wt% and stirring velocity are to carry out hydrogenation reaction under the condition of 500 revs/min, reaction heat shifts out by the coil pipe of hydrogenation reactor and the water coolant in chuck; DNT raw material is average stop after 3.0h in reactor, and liquid product imports catalyst separator I from hydrogenation reactor bottom through pipeline 5, and carries out pressure equilibrium by pipeline 8 with catalyst separator I.

B. from the liquid product of hydrogenation reactor after the average stop 1.5h in catalyst separator I, upper clear supernate is added in settlement separator II through pipeline 12, and sedimentation catalyst slurry is first back in hydrogenation reactor by pipeline 9,10 and 6 by pump, the catalyst slurry of returning to hydrogenation reactor is 2.5 with removing the mass ratio of the clear liquid of catalyst separator II; Gas phase enters through pipeline 13 separator of exitting of speeding from top; The venting of speeding of speeding to exit in separator is through pipeline 14 emptying or recycling, and isolated liquid phase is back in hydrogenation reactor through pipeline 7.

C. the clear liquid that autocatalysis agent separator I comes carries out secondary settlement in catalyst separator II, settling time is 3.5h, the catalyst slurry of sedimentation is first back in hydrogenation reactor by pipeline 15,11 and 6 by pump, and clear liquid obtains thick TDA product after being filtered, it is 4.0 that catalyst separator II removes the clear liquid of strainer and the mass ratio that returns to the catalyst slurry of hydrogenation reactor; It is one standby that strainer one leaves, the lower small catalyst particles elder generation of strainer filter by high pressure nitrogen through pipeline 18 blowbacks to spent catalyst storage tank, then by the de-salted water from pipeline 22, regularly it is cleaned, the spent catalyst slip after cleaning is also delivered to spent catalyst storage tank through pipeline 18.

The quality that catalyzer prepared by the present embodiment is measured through ICP forms for details see attached table 3; Catalyst activity data are all measured on the industrial side line device of 3000 tons/year, and concrete technology is shown in accompanying drawing 4, and process portion operating parameters and product form for details see attached table 3.

Embodiment 5

2 μ m nickel powders, 15 μ m aluminium powders and 4 μ m promoter metal powder be take to massfraction to be mixed as Ni45wt%-Al50wt%-auxiliary agent (Fe+Cr+Mo) 5wt%, being placed on bottom has funnel and around inlays in the crucible of SiC, with microwave, with the speed of 40 ℃/min, be heated to 1400 ℃ of meltings, after the Ar of 0.9MPa gasifies atomization, obtain alloy powder, rate of cooling is 1.5 * 10 ⁶k/s; Mass ratio by alloy powder and NaOH powder with 1.4:1 mixes, and at normal temperatures the distilled water of 5 times of alloy powder volumes is dropped in container, and rate of addition keeps mix wetting evenly but do not form liquid phase; Suspension liquid after dropping is finished is at 70kHZ, and ultrasonic 20min under the condition of 40 ℃ then obtains catalyzer after distilled water wash, is kept in water standby.Catalyzer prepared by this embodiment is as follows for concrete technology route and the reaction conditions of hydrogenation of dinitro toluene:

A. the Raney-Ni catalyzer of preparation and DNT are configured to the live catalyst slip that catalyst quality content is 10wt% in live catalyst storage tank, and the speed with 10kg/h is added in hydrogenation reactor through pipeline 4; Raw material DNT and hydrogen are squeezed in hydrogenation reactor through pipeline 1 and 2 respectively, and at H ₂with the mol ratio of DNT charging be that 6.4:1, temperature of reaction are that 115 ℃, reaction pressure are that 1.0MPa, catalyst quality content are that 3wt% and stirring velocity are to carry out hydrogenation reaction under the condition of 400 revs/min, reaction heat shifts out by the coil pipe of hydrogenation reactor and the water coolant in chuck; DNT raw material is average stop after 3.0h in reactor, and liquid product imports catalyst separator I from hydrogenation reactor bottom through pipeline 5, and carries out pressure equilibrium by pipeline 8 with catalyst separator I.

B. from the liquid product of hydrogenation reactor after the average stop 1.6h in catalyst separator I, upper clear supernate is added in settlement separator II through pipeline 12, and sedimentation catalyst slurry is first back in hydrogenation reactor by pipeline 9,10 and 6 by pump, the catalyst slurry of returning to hydrogenation reactor is 3.0 with removing the mass ratio of the clear liquid of catalyst separator II; Gas phase enters through pipeline 13 separator of exitting of speeding from top; The venting of speeding of speeding to exit in separator is through pipeline 14 emptying or recycling, and isolated liquid phase is back in hydrogenation reactor through pipeline 7.

Embodiment 6

4 μ m nickel powders, 5 μ m aluminium powders and 5 μ m promoter metal powder be take to massfraction to be mixed as Ni49wt%-Al55wt%-Cr1wt%, being placed on bottom has funnel and around inlays in the crucible of SiC, with microwave, with the speed of 30 ℃/min, be heated to 1600 ℃ of meltings, after the Ar of 1.0MPa gasifies atomization, obtain alloy powder, rate of cooling is 1.5 * 10 ⁶k/s; Mass ratio by alloy powder and NaOH powder with 1.5:1 mixes, and at normal temperatures the distilled water of 4 times of alloy powder volumes is dropped in container, and rate of addition keeps mix wetting evenly but do not form liquid phase; Suspension liquid after dropping is finished is at 80kHZ, and ultrasonic 40min under the condition of 40 ℃ then obtains catalyzer after distilled water wash, is kept in water standby.Catalyzer prepared by this embodiment is as follows for concrete technology route and the reaction conditions of hydrogenation of dinitro toluene:

A. the Raney-Ni catalyzer of preparation and DNT are configured to the live catalyst slip that catalyst quality content is 10wt% in live catalyst storage tank, and the speed with 7.5kg/h is added in hydrogenation reactor through pipeline 4; Raw material DNT and hydrogen are squeezed in hydrogenation reactor through pipeline 1 and 2 respectively, and at H ₂with the mol ratio of DNT charging be that 6.4:1, temperature of reaction are that 110 ℃, reaction pressure are that 1.0MPa, catalyst quality content are that 3wt% and stirring velocity are to carry out hydrogenation reaction under the condition of 400 revs/min, reaction heat shifts out by the coil pipe of hydrogenation reactor and the water coolant in chuck; DNT raw material is average stop after 3.0h in reactor, and liquid product imports catalyst separator I from hydrogenation reactor bottom through pipeline 5, and carries out pressure equilibrium by pipeline 8 with catalyst separator I.

Comparative example 1

Adopt equi-volume impregnating to prepare loading type Ni/SiO ₂catalyzer.First by SiO ₂carrier (specific surface area 199.907m ²/ g) standby after 200 ℃ of roasting 2h in retort furnace.Compound concentration is the soluble salt (MoCl of 0.1moL/L nickelous nitrate and finite concentration auxiliary agent respectively ₅, La (NO ₃) ₃, CoCl ₂6H ₂o and ZrOCl ₂8H ₂o) mixing solutions, by SiO ₂powder joins in above-mentioned solution, under agitation condition, flood 12h, then be placed in baking oven in 110 ℃ of dry 11h, dried precursor is ground and is placed in retort furnace in 500 ℃ of roasting 4h, sieve is got 80～100 object particles, has both obtained (NiO+ auxiliary agent oxide compound)/SiO that charge capacity is 28wt% ₂presoma.By catalyst precursor in 500 ℃ at gas mixture 90%N ₂-10%H ₂under atmosphere, reduce 5h, and in nitrogen atmosphere, be down to the room temperature loaded catalyst that gets product, be kept in reagent bag or water standby.

This comparative example is to carry out under the optimum preparation condition of loading type nickel-based catalyst, choose and add respectively La, Mo, the Uru shibara nickel catalyst of Co and tetra-kinds of auxiliary agents of Zr is comparative catalyst, wherein promoter addition is 6% of Ni molar weight, further by catalyzer called after FZ _ni-La, FZ _ni-Mo, FZ _ni-Coand FZ _ni-Zr, concrete data see attached list 1, and concrete evaluation procedure is as follows:

Catalyst activity evaluation procedure:

By 40g dinitrotoluene (DNT) raw material and 200ml solvent (H ₂o38.9～39.4wt%+TDA60.6～61.1wt%, from the thick TDA product of the huge power in Yantai) put into 500ml beaker, after melting in 70 ℃ of water-baths, be poured in 500ml reactor, add 6g catalyzer simultaneously.At ambient temperature, use respectively N ₂and H ₂replacement reaction kettle three times, the punching press of rear use hydrogen, to 1MPa or 2MPa, checks resistance to air loss.With 10 ℃/min, rise to 110 ℃, and start reaction under 500r/min stirs, in reaction process, constantly pass into H ₂to maintain still internal pressure, after reaction 2h, finish.

Catalyst life evaluation procedure:

By 40g dinitrotoluene (DNT) and 250mL solvent (H ₂o38.9～39.4wt%+TDA60.6～61.1wt%, from the thick TDA product of the huge power in Yantai) put into 500ml beaker, after melting in 70 ℃ of water-baths, be poured in 500ml reactor, add 10g catalyzer simultaneously.Under room temperature condition, by high pure nitrogen, rush and bleed off pressure 4 times to remove the residual air in reactor, then with high-purity hydrogen, replace 5 backlash to 1MPa.With 10 ℃/min, rise to 110 ℃, and start reaction under 500r/min stirs, in reaction process, constantly pass into H ₂to maintain still internal pressure, after reaction 60min, first set reaction finishes, open tapping switch, 100ml reaction solution is passed through to strainer and after condensation, discharges and analyze, then open sampling pump and 40ml raw material DNT liquid phase is squeezed in reactor and start reaction, after reaction 30min, finish, then repeat setting-out and sample introduction operation above, by analyzing the DNT content in each product, the activity of catalyzer is monitored.

Comparative example 2

Taking 6.5g zinc powder and will fully mix with 5ml water under agitation condition, is 1mol/L NiCl by 25ml concentration ₂with promoter soluble salt (MoCl ₅, La (NO ₃) ₃, CoCl ₂6H ₂o and ZrOCl ₂8H ₂o) mixing solutions is added in the suspension of zinc powder, under agitation condition, after 80 ℃ of reaction 6h, finish, precipitation is leached, and after water washing three times, join in the acetum that 150ml concentration is 2mol/L, under agitation condition in 50 ℃ of reaction 2h, finally respectively after water and washing with alcohol three times finished catalyst.

This comparative example is to carry out under the optimum preparation condition of lacquer original nickel, has chosen interpolation La, Mo, and the Uru shibara nickel catalyst of Co and tetra-kinds of auxiliary agents of Zr is comparative catalyst, wherein promoter addition is 6% of Ni molar weight, further by catalyzer called after QY _ni-La, QY _ni-Mo, QY _ni-Coand QY _ni-Zr, concrete evaluation procedure is shown in comparative example 1, concrete data see attached list 1.

Comparative example 3

Adopt chemical preparation Ni-B amorphous alloy catalyst.In beaker, add a certain amount of 0.1molL ^-1acetic acid nickel (AC) ₂and promoter soluble salt (MoCl ₅, La (NO ₃) ₃, CoCl ₂6H ₂o and ZrOCl ₂8H ₂o) mixed aqueous solution, and be placed in the ice-water bath of 0 ℃, under the condition stirring, dropwise add 2molL ^-1pOTASSIUM BOROHYDRIDE (A.R., Chemical Reagent Co., Ltd., Sinopharm Group) solution, make KBH ₄/ Ni ²⁺=4:1 after dropping finishes, continues suspension to be stirred to stopped reaction while emitting without gas in ice-water bath.Use deionized water repetitive scrubbing to pH ≈ 7 black precipitate, then by methanol wash, obtain product catalyst three times, be kept in methyl alcohol standby.

This comparative example is to carry out under the optimum preparation condition of Ni-B amorphous alloy catalyst, choose and add respectively La, Mo, the Ni-B catalyzer of Co and tetra-kinds of auxiliary agents of Zr is comparative catalyst, wherein promoter addition is 6% of Ni molar weight, further by catalyzer called after FJT _ni-La, FJT _ni-Mo, FJT _ni-Coand FJT _ni-Zr, concrete evaluation procedure is shown in comparative example 1, concrete data see attached list 1.

Comparative example 4

Adopt ordinary method to prepare Raney's nickel catalyst.By 10g Ni-Al-M alloy powder, (mass ratio of Ni-Al is 1:1, granularity 120～200 orders) put into beaker, and add the distilled water of 10ml, then be placed in the water-bath of 50 ℃, the NaOH aqueous solution that is 16wt% by mass concentration is dropwise added in above-mentioned beaker under agitation condition, rate of addition is 5ml/min, NaOH:Al mol ratio is 3:1, after dropping finishes, bath temperature is risen to 70 ℃, be stirred to without finishing after Bubble formation, water obtains finished catalyst after being washed neutrality processed, is kept in water standby.

This comparative example is that industrial Ni-Al alloy powder is prepared under preparation condition, and its auxiliary agent is respectively La, Mo, and one or more in Co and Zr, for convenience of discussing, further by catalyzer called after RAN _ni-La, RAN _ni-Mo, RAN _ni-Coand RAN _ni-Zr, concrete evaluation procedure is shown in comparative example 1, concrete data see attached list 1.

Comparative example 5

The catalyzer that adopts the embodiment of the present invention 1～6 preparation, carries out activity and life assessment with the disclosed evaluation procedure of comparative example 1 to catalyzer, and contrasts with the catalyzer of comparative example 1～4, and specific performance evaluating data sees attached list 1.

Comparative example 6

By 40g dinitrotoluene (DNT) and 250mL solvent (H ₂o38.9～39.4wt%+TDA60.6～61.1wt%, from the thick TDA product of the huge power in Yantai) put into 500ml beaker, after melting in 70 ℃ of water-baths, be poured in 500ml reactor, add the Raney's nickel catalyst of 10g embodiment 1 preparation simultaneously; Under room temperature condition, by high pure nitrogen, rush and bleed off pressure 4 times, to remove the residual air in reactor, under normal pressure, with 10 ℃/min, rise to 110 ℃, then pass into H ₂punching press, to 1MPa, starts reaction simultaneously under 500r/min stirs, and constantly passes into H in reaction process ₂to maintain still internal pressure, every 5min sampling analysis in reaction process, until in product without finishing after DNT product, by composition and the variation of the product in analytical reaction process, determined the reaction mechanism of raney ni catalysis hydrogenation of dinitro toluene, refer to accompanying drawing 1, and the reaction times of Accurate Determining catalyzer, refer to accompanying drawing 2 (left side).

Comparative example 7

By 40g dinitrotoluene (DNT) and 250mL solvent (H ₂o38.9～39.4wt%+TDA60.6～61.1wt%, thick TDA product from the huge power in Yantai) put into 500ml beaker, after melting in 70 ℃ of water-baths, be poured in 500ml reactor, add 10g precious metal (Pd+Pt)/C catalyzer (commercial catalysts that the huge power in Yantai provides) simultaneously; Under room temperature condition, by high pure nitrogen, rush and bleed off pressure 4 times, to remove the residual air in reactor, under normal pressure, with 10 ℃/min, rise to 110 ℃, then pass into H ₂punching press, to 1MPa, starts reaction simultaneously under 500r/min stirs, and constantly passes into H in reaction process ₂to maintain still internal pressure, every 5min sampling analysis in reaction process, until in product without finishing after DNT product, by composition and the variation of the product in analytical reaction process, in the reaction times of Accurate Determining catalyzer, refer to accompanying drawing 2 (right side).

Comparative example 8

40g dinitrotoluene (DNT) raw material and 200ml deionized water are put into 500ml beaker, after melting, be poured in 500ml reactor the catalyzer that simultaneously adds 6g to prepare in 70 ℃ of water-baths under the condition of embodiment 1～6; At ambient temperature, use respectively N ₂and H ₂replacement reaction kettle three times, rear with hydrogen punching press to 0.9～1.1MPa, after inspection resistance to air loss, with 10 ℃/min, rise to 95～115 ℃, and start reaction under 500R/min stirs, in reaction process, constantly pass into H ₂to maintain still internal pressure, after reaction 2h, finish, concrete activity rating data see attached list 2.Fundamentally solved two kinds of industrial hydrogenation of dinitro toluene technology as Sweden, the reaction that the catalyzer that exists in Dupont technology is expensive, exist in the easy inactivation of catalyzer and separation difficulty and BASF technology needs plus solvent, reaction pressure is high and facility investment is large problem.

Subordinate list 1

Subordinate list 2

Subordinate list 3

Note: the mass percent that the numeric suffix during catalyzer forms is each element.

Claims

1. by a technique for the synthetic tolylene diamine of dinitrotoluene (DNT) low-voltage hydrogenation, it is characterized in that comprising the steps:

(1) fresh Raney's nickel catalyst and dinitrobenzene are configured to live catalyst slip in live catalyst storage tank, and are added in hydrogenation reactor; Raw material dinitrobenzene and hydrogen add in hydrogenation reactor and react respectively, and reaction heat shifts out by the coil pipe of hydrogenation reactor and the water coolant in chuck; The liquid product of reaction imports catalyst separator I from hydrogenation reactor bottom, and carries out pressure equilibrium by pipeline and catalyst separator I;

(3) after being filtered from the clear liquid at catalyst separator II middle part crude cresylic acid two amine products; It is one standby that strainer one leaves, the lower small catalyst particles elder generation of strainer filter by high pressure nitrogen blowback to spent catalyst storage tank, then by coming de-salted water regularly strainer to be cleaned, spent catalyst slip after cleaning is delivered to spent catalyst storage tank, from gas phase emptying or the recycling at catalyst separator II top, and the catalyst slurry of sedimentation is back to hydrogenation reactor from catalyst separator I bottom.

2. the catalyzer using in a kind of technique by the synthetic tolylene diamine of dinitrotoluene (DNT) low-voltage hydrogenation as claimed in claim 1, it is characterized in that described Raney's nickel catalyst quality group becomes Ni85～90wt%, Al5～10wt%, promoter metal 2～7wt%, promoter metal is one or more in Fe, Cr and Mo.

3. in a kind of technique by the synthetic tolylene diamine of dinitrotoluene (DNT) low-voltage hydrogenation as claimed in claim 1, use the preparation method of catalyzer, it is characterized in that comprising the steps:

4. as claimed in claim 1 a kind of by the technique of the synthetic tolylene diamine of dinitrotoluene (DNT) low-voltage hydrogenation, the condition that it is characterized in that step (1) hydrogenation is that temperature of reaction is 95～115 ℃, reaction pressure is 0.9～1.1MPa, the mol ratio of hydrogen feed and dinitrobenzene charging is 6.0～6.5, and stirring velocity is 350～500 revs/min.

5. as claimed in claim 1 a kind of by the technique of the synthetic tolylene diamine of dinitrotoluene (DNT) low-voltage hydrogenation, it is characterized in that the mean residence time of step (1) DNT raw material in hydrogenation reactor is 2.5～3.5h.

6. as claimed in claim 1 a kind of by the technique of the synthetic tolylene diamine of dinitrotoluene (DNT) low-voltage hydrogenation, it is characterized in that step (1) is in the start-up of reaction, in hydrogenation reactor, with pure water, make solvent, after device is stable, the liquid phase of reactor outlet consists of: H ₂o36.5～37.5wt%, TDA58.5～59.5wt%, catalyzer 3～5wt%.

7. as claimed in claim 1 a kind of by the technique of the synthetic tolylene diamine of dinitrotoluene (DNT) low-voltage hydrogenation, it is characterized in that described reaction liquid phase is 1.5～1.6h in the average retention time of catalyst separator I, removing the supernatant liquor of catalyst separator II and catalyst slurry mass ratio that catalyst separator I returns to hydrogenation reactor is 2.2～2.5.

8. as claimed in claim 1 a kind of by the technique of the synthetic tolylene diamine of dinitrotoluene (DNT) low-voltage hydrogenation, it is characterized in that reacting liquid phase is 2.5～3.5h in the average retention time of catalyst separator II, and removing the clear liquid of strainer and catalyst slurry mass ratio that catalyst separator II returns to hydrogenation reactor is 3.5～4.5.

9. as claimed in claim 1 a kind of by the technique of the synthetic tolylene diamine of dinitrotoluene (DNT) low-voltage hydrogenation, it is characterized in that the mass content of the catalyzer in step (1) live catalyst storage tank is 10wt%.

10. as claimed in claim 1 a kind of by the technique of the synthetic tolylene diamine of dinitrotoluene (DNT) low-voltage hydrogenation, it is characterized in that the continuously feeding speed of step (1) live catalyst slip is 0.25～0.5% of dinitrotoluene (DNT) input speed.