US008153076B2

(12) United States Patent (10) Patent No.: US 8,153,076 B2

Hassan et al. (45) Date of Patent: Apr. 10, 2012
(54) SYSTEMAND PROCESS FOR PRODUCTION (56) References Cited
OF ANILINE AND TOLUENEDAMINE
U.S. PATENT DOCUMENTS
(75) Inventors: Abbas Hassan, Sugar Land, TX (US); 2.463,975 A 4, 1945 Johnson
Ebrahim Bagherzadeh, Sugar Land, TX 2,664.433 A 12, 1953 Hudson ......................... 518,706
(US); Rayford G. Anthony, College 3,636,152 A * 1/1972 Szigeth .............. ... 564,420
3,637.820 A * 1/1972 Dodman et al. ................ 562/68
Station, TX (US); Gregory G. 3,781,320 A 12, 1973 Irwin
Borsinger, Chatham, NJ (US): Aziz 3,892,798 A * 7/1975 Heegetal. ...................... 560.94
Hassan, Sugar Land, TX (US) 3,963,640 A * 6/1976 Smith ............................. 516.79
4,275,034 A * 6/1981 Friedman et al. .. ... 422,643
4,571.437 A * 2/1986 Caskey et al. ................. 564, 418
(73) Assignee: H R D Corporation, Houston, TX (US)
(Continued)
(*) Notice: Subject to any disclaimer, the term of this FOREIGN PATENT DOCUMENTS
patent is extended or adjusted under 35
U.S.C. 154(b) by 0 days. CN 1528.737 A 9, 2004
(Continued)
(21) Appl. No.: 12/568,155 OTHER PUBLICATIONS
(22) Filed: Sep. 28, 2009 IKA Rotor/Stator Generators—2003 Process Catalog.*

(65) Prior Publication Data (Continued)

US 201O/OO15O19 A1 Jan. 21, 2010 Primary Examiner – Walter D Griffin
Assistant Examiner — Huy-Tram Nguyen
Related U.S. Application Data (74) Attorney, Agent, or Firm — Timothy S. Westby: Porter
Hedges LLP
(62) Division of application No. 12/141,196, filed on Jun. (57) ABSTRACT
18, 2008.
A method for producing aniline or toluenediamine is dis
(60) Provisional application No. 60/946,493, filed on Jun. closed which comprises forming a dispersion comprising
27, 2007, provisional application No. 60/946,469, hydrogen gas bubbles dispersed in a liquid medium compris
filed on Jun. 27, 2007. ing either nitrobenzene or dinitrotoluene, wherein the hydro
gen gas bubbles have a mean diameter less than 1 micron; and
(51) Int. C. Subjecting the dispersion to hydrogenation reaction promot
BOI. I/18 (2006.01) ing conditions comprising pressure less than about 600 kPa
(52) U.S. C. .......... 422/225; 366/342: 366/302:44/301; and temperature less than about 200° C., whereby at least a
44/302:516/197 portion of the nitrobenzene or dinitrotoluene is hydrogenated
(58) Field of Classification Search .................. 422/225; to form aniline or toluenediamine, respectively. A system for
366/364, 342, 302; 44/301, 302; 516/197 carrying out the method is also disclosed.
See application file for complete search history. 22 Claims, 2 Drawing Sheets

1N

22N
21
 US 8,153,076 B2
Page 2

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U.S. Patent Apr. 10, 2012 Sheet 1 of 2 US 8,153,076 B2

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U.S. Patent Apr. 10, 2012 Sheet 2 of 2 US 8,153,076 B2

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 US 8,153,076 B2
1. 2
SYSTEMAND PROCESS FOR PRODUCTION Toluenediamine (TDA) exists in several isomeric forms.
OF ANILINE AND TOLUENEDAMINE The TDAs are large-volume intermediates used in the pro
duction of a wide variety of industrial and consumer products,
CROSS-REFERENCE TO RELATED including explosives (TNT), dyes and plastics. The mixture
APPLICATIONS of 2.4- and 2.6-isomers is used predominantly as an interme
diate in the manufacture of toluene diisocyanate. Commercial
This application is a divisional application which claims mixtures of 2.3- and 3.4-isomers, as well as the 2.4- and
the benefit under 35 U.S.C. S 121 of U.S. patent application 2,6-isomers, are used as co-reactants or as raw materials in the
Ser. No. 12/141,196, filed Jun. 18, 2008, which claims the 10
manufacture of urethane products, dyes, corrosion inhibitors,
benefit under 35 U.S.C. S 119(e) of U.S. Provisional Patent and rubber antioxidants. The most commonly marketed iso
Application No. 60/946,493 filed Jun. 27, 2007, and U.S. mers and isomer mixtures are 2,4-TDA, 3,4-TDA, m-TDA
Provisional Patent Application No. 60/946,469 filed Jun. 27, (an 80:20 or 65:35 mixture of the 2.4- and 2,6-isomers), and
2007, the disclosures of each of which are hereby incorpo o-TDA (3.4-, 2.3-isomers, as 60:40 mixture); 2.5-TDA is also
rated herein by reference. 15 marketed in Small quantities. Any single commercial product
will contain various levels of the other isomers. TDAs are
STATEMENT REGARDING FEDERALLY typically produced from dinitrotoluenes through a liquid
SPONSORED RESEARCH ORDEVELOPMENT phase catalytic hydrogenation process, or by the reaction of
iron and hydrochloric acid with the dinitrotoluenes. Byprod
Not Applicable. ucts of the reactions include water and organic by-products,
TECHNICAL FIELD
which are separated from the TDA product based on their
lower or higher boiling points. Most existing processes and
production facilities for toluenediamine oraniline are subject
The present invention generally relates to the gas-liquid to a variety of constraints such as product yield, plant size,
phase catalyzed hydrogenation of nitrobenzene or methyl 25 energy consumption and mass flow limitations. Accordingly,
dinitrobenzene (dinitrotoluene) to produce the corresponding there is continuing interest in improving the ways that aniline
aromatic amines aniline or toluenediamine, respectively. and toluenediamine are produced.
More particularly, the invention relates to apparatus and
methods for producing those aromatic amines, which employ SUMMARY
high shear mixing of the reactants. 30
In accordance with certain embodiments of the invention, a
BACKGROUND method is provided for producing aniline or toluenediamine,
which includes forming a dispersion comprising hydrogen
Aniline is widely used in the production of methylene gas bubbles dispersed in a liquid medium comprising either
diphenyl diisocyanate (MDI), a key intermediate for polyure 35 nitrobenzene or dinitrotoluene, wherein the hydrogen gas
thanes and automotive plastics, and is used to produce anti bubbles have a mean diameter less than 1 micron; and sub
oxidants and Vulcanization accelerators for rubber, and as an jecting the dispersion to hydrogenation reaction promoting
intermediate in the production of herbicides, pesticides, dyes conditions comprising pressure less than about 600 kPa and
and pigments, among many other uses. Today it is typically temperature less than about 200°C., whereby at least a por
produced by catalytic hydrogenation of nitrobenzene, or less 40 tion of the nitrobenzene or dinitrotoluene is hydrogenated to
commonly, by amination of phenol. Catalytic hydrogenation form aniline or toluenediamine, respectively. In some
of nitrobenzene is highly exothermic, having a heat of reac embodiments, the gas bubbles have a mean diameter of less
tion of about 130 kilocalories per mol. The reaction is carried than 400 nm.
out commercially in the presence of excess hydrogen in both In accordance with certain embodiments of the present
the vapor phase and the liquid phase. Vapor-phase processes 45 invention, a method is provided for producing aniline, com
typically employ either fixed-bed or fluidized-bed reactors. prising: forming a dispersion comprising hydrogen gas
Catalysts of palladium or copper on activated carbon or alter bubbles dispersed in a liquid medium comprising nitroben
nate Support, often in combination with other metals selected Zene, wherein the bubbles have a mean diameter less than 1
from the group consisting of lead, Vanadium, phosphorous, micron; and Subjecting the dispersion to hydrogenation reac
and chromium as modifiers/promoters have proven to be 50 tion promoting conditions, whereby at least a portion of the
effective for vapor-phase hydrogenation. High activity and nitrobenzene is hydrogenated to form aniline. In some
selectivity have been obtained with these catalysts. Hydroge embodiments, the reaction promoting conditions comprise
nation of nitrobenzene in the liquid phase has been performed contacting the dispersion with a hydrogenation catalyst. In
with slurry or fluidized-bed reactors. Operating conditions Some embodiments, the reaction promoting conditions fur
are typically a temperature in the range of from about 90° C. 55 ther comprise a pressure less than about 600 kPa and a tem
to about 200° C. and pressure in the range of from about 100 perature less than about 200°C.
kPa to about 600 kPa. In some cases, the liquid phase process Also provided in accordance with certain embodiments of
utilizes an excess of aniline as the reaction solvent and the invention is a method for producingtoluenediamine, com
removes heat produced via the reaction by allowing the reac prising: forming a dispersion comprising hydrogen gas
tion mixture to boil offat a reaction pressure usually less than 60 bubbles dispersed in a liquid medium comprising dinitrotolu
100 kPa. One catalyst that has been used for the liquid process ene, wherein the bubbles have a mean diameter less than 1
is finely divided nickel on diatomite. One continuous liquid micron; and Subjecting the dispersion to hydrogenation reac
phase hydrogenation process is carried out in a plug-flow tion promoting conditions, whereby at least a portion of the
reactor with a platinum-palladium catalyst on a carbon Sup dinitrotoluene is hydrogenated to form toluenediamine. In
port, with iron as modifier. The modifier is used to provide 65 Some embodiments, the reaction promoting conditions com
good catalyst life, high activity, and protection against aro prise contacting the dispersion with a hydrogenation catalyst.
matic ring hydrogenation. In some embodiments, the reaction promoting conditions
 US 8,153,076 B2
3 4
further comprise a pressure less than about 600 kPa and a System for Production of Aniline or Toluenediamine.
temperature less than about 200° C. A high shear aniline or toluenediamine production system
Also provided in accordance with certain embodiments of will now be described in relation to FIG.1, which is a process
the invention is a system for production of aniline from flow diagram of an embodiment of a high shear system 1 for
nitrobenzene or for producing toluenediamine from dinitro the production of aniline by gas-liquid phase hydrogenation
toluene. The system comprises at least one high shear mixing of nitrobenzene, or for the production of toluenediamine by
device configured for producing a dispersion of hydrogen gas gas-liquid phase hydrogenation of dinitrotoluene. The basic
bubbles in a liquid medium comprising either nitrobenzene or components of a representative system include external high
dinitrotoluene, wherein the dispersion has a mean bubble shear mixing device (HSD) 40, vessel 10, and pump 5. As
diameter of less than 400 nmi; a pump configured for deliver 10 shown in FIG. 1, the high shear device is located external to
ing a liquid stream comprising nitrobenzene ordinitrotoluene vessel/reactor 10. Each of these components is further
to the high shear mixing device; and a vessel configured for described in more detail below. Line 21 is connected to pump
receiving the dispersion from the high shear mixer and for 5 for introducing either nitrobenzene or dinitrotoluene reac
maintaining a predetermined pressure and temperature. In tant. Line 13 connects pump 5 to HSD 40, and line 18 con
15 nects HSD 40 to vessel 10. Line 22 is connected to line 13 for
Some embodiments, the vessel comprises a hydrogenation introducing dispersible molecular hydrogen. Line 17 is con
catalyst. These and other embodiments and potential advan nected to vessel 10 for removal of unreacted nitrobenzene or
tages will be apparent in the following detailed description dinitrotoluene vapor, and other Volatile reaction gases. Addi
and drawings. tional components or process steps may be incorporated
between vessel 10 and HSD 40, or ahead of pump 5 or HSD
BRIEF DESCRIPTION OF THE DRAWINGS 40, if desired. For example, line 16 may be connected to line
21 or line 13, to provide for multi-pass operation, if desired.
FIG. 1 is a process flow diagram of a process for production High Shear Mixing Device. External high shear mixing
of either aniline or toluenediamine, according to certain device (HSD) 40, also sometimes referred to as a high shear
embodiments of the invention. 25 mixer, is configured for receiving an inlet stream via line 13,
FIG. 2 is a longitudinal cross-section view of a multi-stage comprising liquid nitrobenzene or dinitrotoluene and
high shear device, as employed in an embodiment of the molecular hydrogen. Alternatively, HSD 40 may be config
system of FIG. 1. ured for receiving the liquid and gaseous reactant streams via
separate inlet lines (not shown). Although only one high shear
DETAILED DESCRIPTION OF THE PREFERRED 30 device is shown in FIG. 1, it should be understood that some
EMBODIMENTS embodiments of the system may have two or more high shear
mixing devices arranged either in series or parallel flow. HSD
The present methods and systems for the production of 40 is a mechanical device that utilizes one or more generators
aniline and toluenediamine via gas-liquid phase partial oxi comprising a rotor/stator combination, each of which has a
dation of nitrobenzene and dinitrotoluene, respectively, 35 fixed gap between the stator and rotor. HSD 40 is configured
employ an external high shear mechanical device to provide in Such a way that it is capable of producing Submicron (i.e.,
rapid contact and mixing of chemical ingredients in a con less than 1 micron in diameter) and micron-sized bubbles in a
trolled environment in the mixing device. The high shear reactant mixture flowing through the mixer. The high shear
device reduces the mass transfer limitations on the reaction mixer comprises an enclosure or housing so that the pressure
40 and temperature of the reaction mixture may be controlled.
and thus increases the overall reaction rate. For the purposes High shear mixing devices are generally divided into three
of this disclosure, "dinitrotoluene' and “toluenediamine' general classes, based upon their ability to mix fluids. Mixing
include the corresponding isomers, and mixtures thereof. is the process of reducing the size of particles or inhomoge
Chemical reactions involving liquids, gases and Solids rely neous species within the fluid. One metric for the degree or
on the laws of kinetics that involve time, temperature, and 45 thoroughness of mixing is the energy density per unit volume
pressure to define the rate of reactions. In cases where it is that the mixing device generates to disrupt the fluid particles.
desirable to react two or more raw materials of different The classes are distinguished based on delivered energy den
phases (e.g. Solid and liquid; liquid and gas; Solid, liquid and sities. Three classes of industrial mixers having Sufficient
gas), one of the limiting factors in controlling the rate of energy density to consistently produce mixtures or emulsions
reaction involves the contact time of the reactants. In the case 50 with particle sizes in the range of submicron to 50 microns
of heterogeneously catalyzed reactions there is the additional include homogenization valve systems, colloid mills and high
rate limiting factor of having the reacted products removed speed mixers. In the first class of high energy devices, referred
from the surface of the catalyst to enable the catalyst to to as homogenization valve systems, fluid to be processed is
catalyze further reactants. Contact time for the reactants and/ pumped under very high pressure through a narrow-gap valve
or catalyst is often controlled by mixing which provides con 55 into a lower pressure environment. The pressure gradients
tact with two or more reactants involved in a chemical reac across the valve and the resulting turbulence and cavitation
tion. A reactor assembly that comprises an external high shear act to break-up any particles in the fluid. These valve systems
device or mixer as described herein makes possible decreased are most commonly used in milk homogenization and can
mass transfer limitations and thereby allows the reaction to yield average particle sizes in the 0-1 micron range.
more closely approach kinetic limitations. When reaction 60 At the opposite end of the energy density spectrum is the
rates are accelerated, residence times may be decreased, third class of devices referred to as low energy devices. These
thereby increasing obtainable throughput. Product yield may systems usually have paddles or fluid rotors that turn at high
be increased as a result of the high shear system and process. speed in a reservoir of fluid to be processed, which in many of
Alternatively, if the product yield of an existing process is the more common applications is a food product. These low
acceptable, decreasing the required residence time by incor 65 energy systems are customarily used when average particle
poration of suitable high shear may allow for the use of lower sizes of greater than 20 microns are acceptable in the pro
temperatures and/or pressures than conventional processes. cessed fluid.
 US 8,153,076 B2
5 6
Between the low energy devices and homogenization valve tured by IKAR Works, Inc. Wilmington, N.C. and APV North
systems, in terms of the mixing energy density delivered to America, Inc. Wilmington, Mass., for example. In some
the fluid, are colloid mills, which are classified as intermedi instances, HSD 40 comprises the DISPAX REACTORR) of
ate energy devices. A typical colloid mill configuration IKAR Works, Inc. Several models are available having vari
includes a conical or disk rotor that is separated from a ous inlet/outlet connections, horsepower, nominal tip speeds,
complementary, liquid-cooled Stator by a closely-controlled output rpm, and nominal flow rate. Selection of a particular
rotor-stator gap, which is commonly between 0.0254-10.16 device will depend on specific throughput requirements for
mm (0.001-0.40 inch). Rotors are usually driven by an elec the intended application, and on the desired bubble size in the
tric motor through a direct drive or belt mechanism. As the outlet dispersion from the high shear mixer. The high shear
rotor rotates at high rates, it pumps fluid between the outer 10 device comprises at least one revolving element that creates
surface of the rotor and the inner surface of the stator, and the mechanical force applied to the reactants. In some
shear forces generated in the gap process the fluid. Many embodiments, the high shear device comprises at least one
colloid mills with proper adjustment achieve average particle stator and at least one rotor separated by a clearance. For
sizes of 0.1-25 microns in the processed fluid. These capa example, the rotors may be conical or disk shaped and may be
bilities render colloid mills appropriate for a variety of appli 15 separated from a complementary-shaped stator. Both the
cations including colloid and oil/water-based emulsion pro rotor and stator may comprise a plurality of circumferen
cessing such as that required for cosmetics, mayonnaise, or tially-spaced teeth. In some embodiments, the stator(s) are
silicone/silver amalgam formation, to roofing-tar mixing. adjustable to obtain the desired gap between the rotor and the
An approximation of energy input into the fluid (kW/L/ stator of each generator (rotor/stator set). Grooves in the rotor
min) can be estimated by measuring the motor energy (kW) and/or stator may change directions in alternate stages for
and fluid output (L/min). Tip speed is the circumferential increased turbulence. Each generator may be driven by any
distance traveled by the tip of the rotor per unit of time. Tip Suitable drive system configured for providing the necessary
speed is thus a function of the rotor diameter and the rota rotation.
tional frequency. Tip speed (in meters per minute, for In some embodiments, the minimum clearance between
example) may be calculated by multiplying the circumferen 25 the stator and the rotor is in the range of from about 0.0254
tial distance transcribed by the rotor tip, 2 tR, where R is the mm to about 3.175 mm (about 0.001 inch to about 0.125
radius of the rotor (in meters, for example) times the fre inch). In certain embodiments, the minimum clearance
quency of revolution (in revolutions per minute). A colloid between the stator and rotor is about 1.524mm (0.060 inch).
mill, for example, may have a tip speed in excess of 22.9 In certain configurations, the minimum clearance between
m/sec (4500 ft/min) and may exceed 40 m/sec (7900 ft/min). 30 the rotor and stator is at least 1.778 mm (0.07 inch). The shear
For the purposes of this disclosure, the term “high shear rate produced by the high shear mixer may vary with longi
refers to mechanical rotor stator devices (e.g., colloid mills or tudinal position along the flow pathway. In some embodi
rotor/stator mixers) that are capable of tip speeds in excess of ments, the rotor is set to rotate at a speed commensurate with
5.1 m/sec. (1000 ft/min) and require an external mechanically the diameter of the rotor and the desired tip speed. In some
driven power device to drive energy into the stream of mate 35 embodiments, the colloidal mill has a fixed clearance
rials to be reacted. For example, in HSD 40, a tip speed in between the stator and rotor. Alternatively, the colloid mill
excess of 22.9 m/sec (4500 ft/min) is achievable, and may has adjustable clearance.
exceed 40 m/sec (7900 ft/min). In some embodiments, HSD In some embodiments, HSD 40 comprises a single stage
40 is capable of delivering at least 300 L/h with a power dispersing chamber (i.e., a single rotor/stator combination, a
consumption of about 1.5 kW at a nominal tip speed of at least 40 single generator). In some embodiments, high shear device 40
22.9 m/sec (4500 ft/min). is a multiple stage inline disperser and comprises a plurality
HSD 40 combines high tip speeds with a very small shear of generators. In certain embodiments, HSD 40 comprises at
gap to produce significant shear on the material being pro least two generators. In other embodiments, high shear device
cessed. The amount of shear will be dependent on the viscos 40 comprises at least 3 high shear generators. In some
ity of the fluid. Accordingly, a local region of elevated pres 45 embodiments, high shear device 40 is a multistage mixer
Sure and temperature is created at the tip of the rotor during whereby the shear rate (which varies proportionately with tip
operation of the high shear device. In some cases the locally speed and inversely with rotor/stator gap) varies with longi
elevated pressure is about 1034.2 MPa (150,000 psi). In some tudinal position along the flow pathway, as further described
cases the locally elevated temperature is about 500° C. In herein below.
Some cases these local pressure and temperature elevations 50 In some embodiments, each stage of the external high shear
may persist for nano or pico seconds. In some embodiments, device has interchangeable mixing tools, offering flexibility.
the energy expenditure of the high shear mixer is greater than For example, the DR2000/4 DISPAX REACTORR) of IKAR
1000 W/m. In embodiments, the energy expenditure of HSD Works, Inc. Wilmington, N.C. and APV North America, Inc.
40 is in the range of from about 3000 W/m to about 7500 Wilmington, Mass., comprises a three stage dispersing mod
W/m. The shear rate is the tip speed divided by the shear gap 55 ule. This module may comprise up to three rotor/stator com
width (minimal clearance between the rotor and stator). The binations (generators), with choice of fine, medium, coarse,
shear rate generated in HSD 40 may be greater than and Super-fine for each stage. This allows for creation of
20,000 s'. In some embodiments the shear rate is at least dispersions having a narrow distribution of the desired bubble
1,600,000 s. In embodiments, the shear rate generated by size. In some embodiments, each of the stages is operated
HSD 40 is in the range of from 20,000 s to 100,000 s. For 60 with Super-fine generator. In some embodiments, at least one
example, in one application the rotor tip speed is about 40 of the generator sets has a rotor/stator minimum clearance of
m/sec (7900 ft/min) and the shear gap width is 0.0254 mm greater than about 5.08 mm (0.20 inch). In some embodi
(0.001 inch), producing a shear rate of 1,600,000 s. ments, at least one of the generator sets has a minimum
HSD 40 is capable of highly dispersing or transporting rotor/stator clearance of greater than about 1.778 mm (0.07
hydrogen gas into a main liquid phase comprising nitroben 65 inch). In some embodiments the rotors are 60 mm and the
Zene or dinitrotoluene. In some embodiments, HSD 40 com stators are 64 mm in diameter, providing a clearance of about
prises a colloid mill. Suitable colloidal mills are manufac 4 mm.
 US 8,153,076 B2
7 8
Referring now to FIG. 2, there is presented a longitudinal ring system, heating and/or cooling capabilities, pressure
cross-section of a suitable high shear device 200. High shear measurement instrumentation, temperature measurement
device 200 is a dispersing device comprising three stages or instrumentation, one or more injection points, and level regu
rotor-stator combinations, 220, 230, and 240. Three rotor/ lator (not shown), as are known in the art of reaction vessel
stator sets or generators 220, 230, and 240 are aligned in 5 design. For example, a stirring system may include a motor
series along drive input 250. The first generator 220 com driven mixer. A heating and/or cooling apparatus may com
prises rotor 222 and stator 227. The second generator 230 prise, for example, a heat exchanger. One or more product
comprises rotor 223, and stator 228; the third generator 240 lines 16 are connected to vessel 10 for removal and recovery
comprises rotor 224 and stator 229. For each generator the of product.
rotor is rotatably driven by input 250 and rotates, as indicated 10 HeatTransfer Devices. In addition to the above-mentioned
by arrow 265, about axis 260. Stator 227 is fixedly coupled to heating/cooling capabilities of vessel 10, other external or
high shear device wall 255. Each generator has a shear gap internal heat transfer devices for heating or cooling a process
which is the distance between the rotor and the stator. First stream are also contemplated in variations of the embodi
generator 220, comprises a first shear gap 225; second gen ments illustrated in FIG.1. Some suitable locations for one or
erator 230 comprises a second shear gap 235; and third gen- 15 more such heat transfer devices are between pump 5 and HSD
erator 240 comprises a third shear gap 245. In some embodi 40, between HSD 40 and vessel 10, and between vessel 10 and
ments, shear gaps 225, 235, 245 are between about 0.025 mm pump 5, if system 1 is operated in multi-pass mode. Some
and 10.0 mm wide. In some embodiments, the process com non-limiting examples of such heat transfer devices are shell,
prises utilization of a high shear device 200 wherein the gaps tube, plate, and coil heat exchangers, as are known in the art.
225, 235, 245 are between about 0.5 mm and about 2.5 mm. 20 Pumps. Pump 5 is configured for either continuous or
In certain instances the gap is maintained at about 1.5 mm. semi-continuous operation, and may be any suitable pumping
Alternatively, the gaps 225, 235, 245 are different for genera device that is capable of providing greater than 203 kPa (2
tors 220, 230, 240. In certain instances, the gap 225 for the atm) pressure, preferably greater than 304 kPa (3 atm) pres
first generator 220 is greater than about the gap 235 for the sure, to allow controlled flow through HSD 40 and system 1.
second generator 230, which is in turn greater than about the 25 For example, a Roper Type 1 gear pump, Roper Pump Com
gap 245 for the third generator. As mentioned above, the pany (Commerce Ga.) Dayton Pressure Booster Pump Model
generators of each stage may be interchangeable, offering 2P372E, Dayton Electric Co (Niles, Ill.) is one suitable pump.
flexibility. Preferably, all contact parts of the pump comprise stainless
Generators 220, 230, and 240 may comprise a coarse, steel, or, if corrosive Substances will be pumped, the contact
medium, fine, and Super-fine characterization. Rotors 222, 30 Surfaces may be gold plated. In some embodiments of the
223, and 224 and stators 227, 228, and 229 may be toothed system, pump 5 is capable of pressures greater than about
designs. Each generator may comprise two or more sets of 2027 kPa (20 atm). In addition to pump 5, one or more
rotor-stator teeth. Rotors 222, 223, and 224 may comprise a additional, high pressure pump (not shown) may be included
number of rotor teeth circumferentially spaced about the cir in the system illustrated in FIG. 1. For example, a booster
cumference of each rotor. Stators 227, 228, and 229 may 35 pump, which may be similar to pump 5, may be included
comprise a complementary number of stator teeth circumfer between HSD 40 and vessel 10 for boosting the pressure into
entially spaced about the circumference of each stator. In vessel 10. As another example, a Supplemental feed pump,
embodiments, the inner diameter of the rotor is about 11.8 which may be similar to pump 5, may be included for intro
cm. In embodiments, the outer diameter of the stator is about ducing additional reactants or catalyst into vessel 10. As still
15.4 cm. In certain embodiments, each of three stages is 40 another example, a compressor type pump may be positioned
operated with a Super-fine generator, comprising a shear gap between line 17 and HSD 40 for recycling unreacted hydro
of between about 0.025 mm and about 3 mm. For any appli gen and other gases or vapors from Vessel 10 to an inlet of the
cations in which solid particles (e.g., catalyst) are to be sent high shear device.
through high shear device 200, shear gap width may be Production of Aniline or Toluenediamine.
selected for reduction in particle size and increase in particle 45 In operation for the catalytic production of aniline from
Surface area. In some embodiments, the disperser is config nitrobenzene, or, alternatively, for the independent produc
ured so that the shear rate will increase stepwise longitudi tion of toluenediamine from dinitrotoluene, a dispersible
nally along the direction of the flow. The IKAR model DR H-containing gas stream is introduced into system 1 via line
2000/4, for example, comprises a belt drive, 4M generator, 22, and combined in line 13 with either a nitrobenzene- or
PTFE sealing ring, inlet flange 25.4 mm (1 inch) sanitary 50 dinitrotoluene-containing liquid stream. For ease of refer
clamp, outlet flange 19 mm (3/4 inch) sanitary clamp, 2 HP ence, the dinitrotoluene isomers are individually and collec
power, output speed of 7900 rpm, flow capacity (water) tively referred to herein as "dinitrotoluene', although it
approximately 300-700 L/h (depending on generator), a tip should be understood that a specific isomer or combination of
speed of from 9.4-41 m/sec (1850 ft/min to 8070 ft/min). isomers could be substituted in place of the generic term
Vessel. Vessel or reactor 10 is any type of vessel in which a 55 where the context allows. Likewise, use of the generic term
multiphase reaction can be propagated to carry out the above “toluenediamine.” in this disclosure represents each of its
described conversion reaction(s). For instance, a fixed bed isomers, individually and collectively, where the context
catalytic reactor, a continuous or semi-continuous stirred tank allows. Alternatively, the hydrogen-containing gas may be
reactor, or one or more batch reactors may be employed in fed directly into HSD 40, instead of being combined with the
series or in parallel. In some applications vessel 10 may be a 60 liquid reactant (i.e., nitrobenzene ordinitrotoluene) in line 13.
tower reactor, and in others a tubular reactor or multi-tubular In some embodiments an aliphatic alcohol solvent and/or
reactor. One or more inlet line 15 may be connected to vessel carbon monoxide is added into line 13 to enhance the hydro
10 for receiving any additional reactants or catalyst during genation process and act as a reaction solvent. The unsubsti
operation of the system. If desired, vessel 10 may be con tuted alkyl monoalcohols contain from 1-8 carbon atoms,
nected to line 21 for recycling unreacted nitrobenzene or 65 and, in some cases, 1-4 carbon atoms. Examples include
dinitrotoluene back into HSD 40 via pump 5. Vessel 10 may methanol, ethyl alcohol, isopropyl alcohol, butyl alcohol,
also include one or more of the following components: stir pentyl alcohol, and mixtures thereof. In many cases, the
 US 8,153,076 B2
10
selected alcohol solvent is methanol. If carbon monoxide is embodiments, the shear rate increases stepwise longitudi
included, especially in the production of toluenediamine, it is nally along the direction of the flow. For example, in some
used in a relatively small proportion, so that the formation of embodiments, the shear rate in the first rotor/stator stage is
toluenediamine is effected primarily via the hydrogen reduc greater than the shear rate in Subsequent stage(s). In other
tion of dinitrotoluene. embodiments, the shear rate is Substantially constant along
Pump 5 is operated to pump the liquid reactant through line the direction of the flow, with the stage or stages being the
21, and to build pressure and feed HSD 40, providing a same. If the high shear mixer includes a PTFE seal, for
controlled flow throughout high shear mixer (HSD) 40 and example, the seal may be cooled using any suitable technique
high shear system 1. In some embodiments, pump 5 increases that is known in the art. For example, the reactant stream
the pressure of the nitrobenzene or dinitrotoluene stream to 10
flowing in line 13 may be used to cool the seal and in So doing
greater than 203 kPa (2 atm), preferably greater than about be preheated as desired prior to entering the high shear mixer.
304 kPa (3 atm). In some embodiments the pressure is about The rotor of HSD 40 is set to rotate at a speed commensu
1013 kPa (10 atm). rate with the diameter of the rotor and the desired tip speed. As
After pumping, the hydrogen and liquid reactants, and any
carbon monoxide or alkyl monoalcohol, are mixed within 15 described above, the high shear mixer (e.g., colloid mill) has
HSD 40, which serves to create a fine dispersion of the hydro either a fixed clearance between the stator and rotor or has
gen gas in the nitrobenzene or dinitrotoluene. In some adjustable clearance. HSD 40 serves to intimately mix the
embodiments it may create a fine mixture, emulsion or dis hydrogen-containing gas and the reactant liquid (i.e.,
persion of the reactants. As used herein, the term “dispersion nitrobenzene or dinitrotoluene). In some embodiments of the
refers to a liquefied mixture that contains two distinguishable process, the transport resistance of the reactants is reduced by
Substances (or phases) that will not readily mix and dissolve operation of the high shear mixer such that the velocity of the
together. A dispersion comprises a continuous phase (or reaction is increased by greater than a factor of about 5. In
matrix), which holds therein discontinuous droplets, bubbles, Some embodiments, the Velocity of the reaction is increased
and/or particles of the other phase or substance. The term by at least a factor of 10. In some embodiments, the velocity
dispersion may thus refer to foams comprising gas bubbles 25 is increased by a factor in the range of about 10 to about 100
Suspended in a liquid continuous phase, emulsions in which fold. In some embodiments, HSD 40 delivers at least 300 L/h
droplets of a first liquid are dispersed throughout a continuous with a power consumption of 1.5 kW at a nominal tip speed of
phase comprising a second liquid with which the first liquid is at least 22.9 m/sec (4500 ft/min), and which may exceed 40
immiscible, and continuous liquid phases throughout which m/sec (7900 ft/min). In some embodiments, the mixture is
solid particles are distributed. The term “dispersion' encom 30
subjected to a shear rate greater than 20,000 s.
passes continuous liquid phases throughout which gas Although measurement of instantaneous temperature and
bubbles are distributed, continuous liquid phases throughout pressure at the tip of a rotating shear unit or revolving element
which solid particles (e.g., Solid catalyst) are distributed, in HSD 40 is difficult, it is estimated that the localized tem
continuous phases of a first liquid throughout which droplets
of a second liquid that is substantially insoluble in the con 35 perature seen by the intimately mixed reactants is in excess of
tinuous phase are distributed, and liquid phases throughout 500° C. and at pressures in excess of 500 kg/cm under cavi
which any one or a combination of solid particles, immiscible tation conditions. The high shear mixing results in dispersion
liquid droplets, and gas bubbles are distributed. Hence, a of the hydrogen-containing gas in micron or Submicron-sized
dispersion can exist as a homogeneous mixture in some cases bubbles (i.e., mean diameter less than 1 micron). In some
(e.g., liquid/liquid phase), or as a heterogeneous mixture 40 embodiments, the resultant dispersion has an average bubble
(e.g., gas/liquid, Solid/liquid, or gas/solid/liquid), depending size less than about 1.5um. Accordingly, the dispersion exit
on the nature of the materials selected for combination. ing HSD 40 via line 18 comprises micron and/or submicron
In HSD 40, the hydrogen-containing gas and nitrobenzene sized gas bubbles. In some embodiments, the mean bubble
or dinitrotoluene are highly dispersed such that nanobubbles size is in the range of about 0.4 um to about 1.5um. In some
and microbubbles of the gaseous reactants, and or, nanodrop 45 embodiments, the mean bubble size less than 400 nm, in the
lets or particles of alcohol, if present, are formed for superior range of about 200 nm to about 400 nm, or it may be about 100
dissolution into Solution and enhancement of reactant mix nm in Some cases. In many embodiments, the microbubble
ing. For example, disperser IKAR model DR 2000/4, a high dispersion is able to remain dispersed at atmospheric pressure
shear, three stage dispersing device configured with three for at least 15 minutes.
rotors in combination with stators, aligned in series, is used to 50 Once dispersed, the resulting gas/liquid dispersion exits
create the dispersion of dispersible hydrogen-containing gas HSD 40 via line 18 and feeds into vessel 10, as illustrated in
in liquid medium comprising nitrobenzene or dinitrotoluene FIG. 1. The dispersion may be further processed prior to
(i.e., “the reactants'). The rotor/stator sets may be configured entering vessel 10, if desired. Hydrogenation of dinitrotolu
as illustrated in FIG. 2, for example. For some applications, ene to form toluenediamine, or of nitrobenzene to form
the direction of rotation of the generators may be opposite that 55 aniline, will occur whenever suitable time temperature and
shown by arrow 265 (e.g., clockwise or counterclockwise pressure conditions exist, facilitated by the presence of a
about axis of rotation 260). The combined gas and liquid Suitable catalyst. In this sense hydrogenation could occur at
reactants enter the high shear mixer and enter a first stage any point in the flow diagram of FIG. 1 if temperature and
rotor/stator combination having circumferentially spaced pressure conditions are Suitable. A discrete reactor is usually
first stage shear openings. In some applications, the direction 60 desirable, however, to allow for the presence of a fixed cata
of flow of the reactant stream entering inlet 205 corresponds lyst, increased residence time, agitation and heating and/or
to the axis of rotation 260. The coarse dispersion exiting the cooling. When a fixed bed catalyst is utilized, the reactor
first stage enters the second rotor/stator stage, having second becomes the main location for the hydrogenation reaction to
stage shear openings. The reduced bubble-size dispersion occur due to the presence of catalyst and its effect on the rate
emerging from the second stage enters the third stage rotor/ 65 of hydrogenation. The catalytic reactor may also be operated
stator combination having third stage shear openings. The as a slurry reactor, trickle bed reactor, fluidized bed reactor,
dispersion exits the high shear mixer via line 18. In some bubble column or other suitable reactor configuration. In
 US 8,153,076 B2
11 12
Some applications, the incorporation of external high shear catalyst particles, thereby facilitating and accelerating the
mixer 40 will allow the operation of trickle bed reactors as catalytic reaction through enhanced transport of reactants.
slurry reactors, for example. The bulk or global operating temperature of the reactants is
Any of a variety of catalysts that are known for promoting desirably maintained below their flash points. In some
these types of reactions may be employed. It is generally 5 embodiments, the operating conditions of system 1 comprise
preferred to employ metallic catalysts including mixtures a temperature in the range of from about 100° C. to about 230°
comprising Such catalysts. These catalysts may be pelleted, C. In embodiments, the temperature is in the range of from
granular or powdered, although for slurry systems the pow about 160° C. to 180°C. In specific embodiments, the reac
dered form is preferred. Such as having a particle size from tion temperature in vessel 10, in particular, is in the range of
about 2 to about 400 microns. For fixed bed systems catalysts 10 from about 155° C. to about 160° C. In some embodiments,
may be either supported on a carrier. Some of the useful the reaction pressure in vessel 10 is in the range of from about
metallic catalysts which may be employed, together with 203 kPa (2 atm) to about 5573 kPa-6080 kPa (55-60 atm). In
references to their preparation, are disclosed in U.S. Pat. No. Some embodiments, reaction pressure is in the range of from
3.232,989 (Graham et al.). A group of catalysts for production about 811 kPa (8 atm) to about 1520 kPa (15 atm). In some
of toluenediamine is nickel, platinum, palladium and mix- 15 embodiments, operating conditions comprise a temperature
tures thereof, one of which is Raney nickel. In some cases, the in the range of about 90° C. to about 200° C. and pressure in
vessel 10 is charged with catalyst and, if required, the catalyst the range of about 100 kPa to about 600 kPa.
is activated according to procedures recommended by the The hydrogenation of 1 mole of nitrobenzene produces 2
catalyst vendors. moles of water and consumes 3 moles of hydrogen for each
Catalyst may be introduced into the vessel via line 15, as an 20 mole of aniline produced. In vessel 10, aniline or toluenedi
aqueous or nonaqueous slurry or stream, or it may be present amine production occurs via catalytic hydrogenation. The
in vessel 10 as a fixed bed, for example. As a result of the temperature of the reactants is controlled (e.g., using a heat
intimate mixing of the H and nitrobenzene or dinitrotoluene exchanger), and the fluid level inside vessel 10 is regulated
reactants prior to entering vessel 10, Some portion of the using standard techniques. The hydrogenation product may
chemical reaction may take place in HSD40, with or without 25 be produced either continuously, semi-continuously or batch
the presence of a catalyst. Accordingly, in Some embodi wise, as desired for a particular application. Any reaction gas
ments, reactor/vessel 10 may be used primarily for heating that is produced exits reactor 10 via gas line 17. This gas
and separation of Volatile reaction products from the aniline stream may comprise unreacted hydrogen and nitrobenzene
or toluenediamine product. In most cases, however, Vessel 10 or dinitrotoluene vapor, for example. The reaction gas
serves as a primary catalytic reaction vessel where most of the 30 removed via line 17 may be further treated, and the compo
aniline or toluenediamine product is produced. In some nents may be recycled, as desired. For example, all or a
embodiments, vessel 10 is a fixed bed catalytic reactor, con portion of hydrogen-containing vent gas in line 17 may be
taining a Suitable hydrogenation catalyst Suitable for cata recycled to line 13 and back into HSD 40 using a compressor
lyzing the hydrogenation of nitrobenzene or dinitrotoluene, type pump. In some embodiments, a portion of unreacted
depending on which reactant liquid is to be hydrogenated. In 35 nitrobenzene or dinitrotoluene in vessel 10 is recycled to high
Some embodiments, dinitrotoluene in contact with the highly shear mixer 40, via line 21, for example. Water produced
dispersed hydrogen bubbles, in the presence of a palladium during the reaction may be removed from vessel 10 prior to
catalyst, is hydrogenated to toluenediamine. In other embodi reuse/recycle.
ments, nitrobenzene in contact with highly dispersed hydro The reaction product stream comprising aniline or toluene
gen bubbles, in the presence of a suitable catalyst, is hydro- 40 diamine, and any non-converted liquid reactant, water, Sol
genated to aniline. Catalyst Suitable for the hydrogenation of vent, and any by-products exits vessel 10 by way of at least
nitrobenzene includes, for example, FeCl and water. In some one line 16. The aniline or toluenediamine may be recovered
embodiments, hydrogenation catalyst comprises finely and treated as known to those of skill in the art, or use as a feed
divided nickel on diatomite. In some embodiments, the cata for further processing. For instance, toluenediamine may be
lyst comprises a platinum-palladium catalyst on a carbon 45 further processed by reacting with phosgene gas to produce
Support. In some embodiments, the catalyst also includes a toluenediisocyanate. Aniline product may be recovered for
modifier, which in some cases comprises iron. For hydroge use as a feed stock in the production of methylene diphenyl
nation of dinitrotoluene, a palladium catalyst is used in some diisocyanate (MDI), which, in turn, is useful for manufactur
embodiments. ing polyurethanes.
Depending on the type of catalytic reactor selected for the 50 Multiple Pass Operation. In the embodiment shown in FIG.
process, catalyst may be added continuously to vessel 10 via 1, the system is configured for single pass operation, wherein
line 15 in some cases. Vessel/reactor 10 may be operated in the output from vessel 10 goes directly to further processing
either continuous or semi-continuous flow mode, or it may be for recovery of aniline or toluenediamine product. In some
operated in batch mode. The contents of vessel 10 may be embodiments it may be desirable to pass the contents of
maintained at a specified reaction temperature using heating 55 vessel 10, or a liquid fraction containing unreacted nitroben
and/or cooling capabilities (e.g., cooling coils) and tempera Zene or dinitrotoluene, through HSD 40 during a second pass.
ture measurement instrumentation. Pressure in the vessel may In this case, line 16 may be joined to line 21, and the recycle
be monitored using Suitable pressure measurement instru stream from vessel 10 pumped by pump 5 into line 13 and
mentation, and the level of reactants in the vessel may be thence into HSD40. Additional hydrogen gas may be injected
controlled using a level regulator (not shown), employing 60 via line 22 into line 13, or it may be added directly into the
techniques that are known to those of skill in the art. The high shear mixer (not shown).
contents are stirred continuously or semi-continuously. With Multiple High Shear Mixing Devices. In some embodi
out wishing to be limited by theory, it is believed that sub ments, two or more high shear devices like HSD 40, or con
micron particles or bubbles dispersed in a liquid undergo figured differently, are aligned in series, and are used to
movement primarily through Brownian motion effects. The 65 further enhance the reaction. Their operation may be in either
nanobubbles in the product dispersion created by HSD 40 batch or continuous mode. In some instances in which a
may have greater mobility through boundary layers of Solid single pass or “once through' process is desired, the use of
 US 8,153,076 B2
13 14
multiple high shear devices in series may also be advanta system and method for the production of aniline or toluene
geous. When multiple high shear devices are operated in diamine include, but are not limited to, faster cycle times,
series, additional reactant(s) may be injected into the inlet increased throughput, higher conversion, reduced operating
feed stream of each device. In some embodiments, multiple costs and/or reduced capital expense due to the possibility of
high shear devices 40 are operated in parallel, and the outlet designing Smaller reactors and/or operating the process at
dispersions therefrom are introduced into one or more vessel lower temperature and/or pressure. Some embodiments of the
10. present methods make possible an increase in the rate of a
The application of enhanced mixing of the reactants by gas/liquid phase hydrogenation process for the production of
HSD 40 potentially causes greater conversion of nitroben toluenediamine from dinitrotoluene and hydrogen gas, or for
Zene to aniline, or greater conversion of dinitrotoluene to 10 the production of aniline from nitrobenzene and hydrogen
toluenediamine, in various embodiments of the method. In gas, by providing for more optimal time, temperature and
Some embodiments, the enhanced mixing potentiates an pressure conditions than are used in other methods. In some
increase in throughput of the process stream. In some embodiments. Such a method employs an external high shear
embodiments, the high shear mixing device is incorporated mechanical reactor to provide enhanced time, temperature
into an established process, thereby enabling an increase in 15 and pressure conditions resulting in accelerated chemical
production (i.e., greater throughput). In contrast to some reactions between multiphase reactants. In still other embodi
methods that attempt to increase the degree of conversion of ments, a high shear method uses an external pressurized high
nitrobenzene or dinitrotoluene by simply increasing reactor shear mixer/reactor to produce aniline or toluenediamine
pressures, the Superior dispersion and/or dissolution provided without the need for large volume reactors or for recovery of
by external high shear mixing may allow in many cases a substantial unconverted nitrobenzene or dinitrotoluene.
decrease in overall operating pressure while maintaining or While preferred embodiments of the invention have been
even increasing reaction rate. Without wishing to be limited to shown and described, modifications thereof can be made by
a particular theory, it is believed that the level or degree of one skilled in the art without departing from the spirit and
high shear mixing is sufficient to increase rates of mass trans teachings of the invention. The embodiments described
fer and may also produce localized non-ideal conditions that 25 hereinare exemplary only, and are not intended to be limiting.
enable reactions to occur that might not otherwise be Many variations and modifications of the invention disclosed
expected to occur based on Gibbs free energy predictions. herein are possible and are within the scope of the invention.
Localized non-ideal conditions are believed to occur within Where numerical ranges or limitations are expressly stated,
the high shear device resulting in increased temperatures and Such express ranges or limitations should be understood to
pressures with the most significant increase believed to be in 30 include iterative ranges or limitations of like magnitude fall
localized pressures. The increase in pressures and tempera ing within the expressly stated ranges or limitations (e.g.,
tures within the high shear device are instantaneous and local from about 1 to about 10 includes, 2, 3, 4, etc.; greater than
ized and quickly revert back to bulk or average system con 0.10 includes 0.11, 0.12, 0.13, and so forth). Use of broader
ditions once exiting the high shear device. In some cases, the terms such as comprises, includes, having, etc. should be
high shear mixing device induces cavitation of Sufficient 35 understood to provide Support for narrower terms such as
intensity to dissociate one or more of the reactants into free consisting of consisting essentially of comprised substan
radicals, which may intensify a chemical reaction or allow a tially of, and the like. Accordingly, the scope of protection is
reaction to take place at less stringent conditions than might not limited by the description set out above but is only limited
otherwise be required. Cavitation may also increase rates of by the claims which follow, that scope including all equiva
transport processes by producing local turbulence and liquid 40 lents of the subject matter of the claims. Each and every
micro-circulation (acoustic streaming). An overview of the original claim is incorporated into the specification as an
application of cavitation phenomenon in chemical/physical embodiment of the invention. Thus, the claims are a further
processing applications is provided by Gogate et al., "Cavi description and are an addition to the preferred embodiments
tation: A technology on the horizon. Current Science 91 (No. of the present invention. The disclosures of all patents, patent
1): 35-46 (2006). The high shear mixing device of certain 45 applications, and publications cited herein are hereby incor
embodiments of the present system and methods is operated porated by reference, to the extent they provide exemplary,
under what is believed to be cavitation conditions effective to procedural or other details supplementary to those set forth
dissociate the hydrogen and liquid reactants into free radicals, herein.
which then form the corresponding aniline ortoluenediamine What is claimed is:
product. 50 1. A system for production of aniline from nitrobenzene,
Certain embodiments of the high shear method make pos the system comprising:
sible a reduction in mass transfer limitations, thereby poten at least one high shear mixing device configured for pro
tially increasing the reaction rate and enabling a reduction in ducing a dispersion of hydrogen gas bubbles in a liquid
reactor temperature, a reduction in reactor pressure, a reduc medium comprising nitrobenzene, wherein the disper
tion in contact time, and/or an increase in product yield. In 55 sion has a mean bubble diameter of less than about 1.5
Some embodiments, the system and methods described herein Lim,
make possible the design of a smaller and/or less capital a pump configured for delivering a feed comprising the
intensive process than previously possible without the use of liquid medium and hydrogen gas to said high shear
the same external high shear mixing. Potential advantages of mixing device, wherein the pump is fluidly connected to
certain embodiments of the disclosed methods are reduced 60 the at least one high shear mixing device via a conduit;
operating costs and increased production from an existing a gas inlet line configured for introducing a dispersible gas
process. Certain embodiments of the disclosed processes comprising hydrogen into said conduit; and
additionally offer the advantage of reduced capital costs for a pressure vessel configured for receiving said dispersion
the design of new processes. In some embodiments, dispers from said high shear mixer and comprising an outlet, and
ing hydrogen-containing gas in Solution prior to hydrogena 65 wherein the pressure vessel is configured to provide
tion decreases the amount of unreacted nitrobenzene or dini Sufficient operating conditions for an exothermic cata
trotoluene. Potential benefits of some embodiments of this lytic reaction of nitrobenzene to form aniline.
 US 8,153,076 B2
15 16
2. The system of claim 1 wherein said high shear mixing 13. The system of claim 12 further comprising a pump on
device comprises a rotor tip and said device is configured for the recycle line.
operating at a flow rate of at least 300 L/h at a tip speed of at 14. The system of claim 1 further comprising apparatus for
least 22.9 m/s. removing from the product at least one component selected
3. The system of claim 1 wherein said high shear mixing from the group consisting of nitrobenzene, liquid medium,
device is configured for operating at a tip speed of at least 40 and water and other by-products of aniline production.
m/s.
4. The system of claim 1 further comprising a recycle line 15. The system of claim 1 wherein said conduit is config
configured for recycling a fluid from the vessel to the at least ured to convey the feed comprising liquid medium and hydro
one high shear mixing device. gen.
10
5. The system of claim 1 wherein the feed further com 16. The system of claim 4 wherein the recycle line is
prises an alkyl monoalcohol, carbon monoxide, or both. configured to recycle a fluid comprising unreacted nitroben
6. The system of claim 5 wherein the alkyl monoalcohol is Zene from the vessel to the pump.
selected from the group consisting of methanol, ethyl alcohol, 17. The system of claim 4 wherein the recycle line connects
isopropyl alcohol, butyl alcohol, pentyl alcohol, and combi 15
the vessel with the conduit.
nations thereof. 18. The system of claim 10 wherein the hydrogenation
7. The system of claim 1 wherein the dispersion has a mean catalyst comprises a metallic catalyst.
bubble diameter of less than 400 nm.
8. The system of claim 1 wherein the at least one high shear 19. The system of claim 18 wherein the metallic catalyst
mixing device comprises at least one rotor and at least one comprises at least one component selected from the group
complementarily-shaped stator. consisting of ferrous chloride, iron, palladium, platinum and
nickel.
9. The system of claim 1 wherein the at least one high shear 20. The system of claim 12 wherein the gas comprises at
mixing device is capable of subjecting the hydrogen gas and
liquid medium to a shear rate of at least 20,000s. least one component selected from the group consisting of
10. The system of claim 1 further comprising a hydroge unreacted nitrobenzene and hydrogen.
nation catalyst within the vessel, the liquid medium, or both, 25
21. The system of claim 1, wherein the pressure vessel is
wherein the hydrogenation catalyst is active for catalyzing the configured to provide an operable reaction pressure of
hydrogenation of nitrobenzene to aniline. between the range of about 150 kPa and 6080 kPa.
11. The system of claim 1 wherein the vessel further com 22. The system of claim 21, wherein the pressure vessel is
prises a vent gas line whereby gas may be removed from the configured to provide an operable reaction pressure of
vessel. 30 between the range of about 811 kPa and 1520 kPa.
12. The system of claim 11 further comprising a recycle
line fluidly connecting the vent gas line with the at least one
high shear mixing device.