Abstract: The invention relates to an esterification unit (150) and esterification process for producing crude methyl methacrylate (MMA) from methacrylamide (MAM), which enable particularly to improve the yield, meaning that the organics spent acids are low; and at the same time, providing crude MMA with rather good quality, meaning that MMA concentration in crude MMA is rather high and preferably from 50 wt % to 80 wt %. According to the invention, the esterification unit comprises esterification reactors (1, . . . , 5 (or 6) set up in a serial way so that there is a counter current flow between gaseous phase and liquid phase, the liquid phase flowing from first reactor (1) of the series to last reactor (5 (or 6)), and the gaseous phase flowing from reactor to first reactor (1).

Abstract: We have discovered that addition of water to a mixture of oxygenates increases their volatility relative to methanol. A process and apparatus are disclosed for separating methanol from other oxygenates. Water is separated from a stream comprising water, methanol and at least one other oxygenate to provide a water rich stream and a methanol and oxygenate rich stream. The methanol and oxygenate rich stream and water are fed to a column to provide an oxygenate rich stream and a methanol and water extract stream. The methanol and water can then be readily separated from each other.

Abstract: A resource recovery method includes: feeding raw water to a first-stage raw water tank; supplying high-temperature vapor to a first-stage heat exchanger; performing heat exchange between the supplied high-temperature vapor and the raw water in the first-stage raw water tank, changing a portion of the water into vapor and supplying the changed vapor to a subsequent-stage heat exchanger; repeatedly performing the performing step for each of the raw water tanks sequentially in the order from a second state to a n-th stage; being feed to a crystallizer from the n-th stage raw water tank; detecting a turbidity of the raw water fed to the crystallizer from the n-th-stage raw water tank; and extracting crystals of valuable resources contained in the raw water fed to the crystallizer from the n-th-stage raw water tank when the turbidity of the raw water becomes a predetermined value.

Abstract: A system and method for producing substantially anhydrous ethanol, methanol or other volatile chemicals includes: (a) a first distillation stripping column or column set with overhead vapors compressed using mechanical vapor recompression to strip off a weak ethanol overheads; (b) a second distillation rectifying column having a higher operating temperature than the stripping column; (c) a dehydration means in fluid communication with the rectifying column; (d) reboiler for the stripping column which partially condenses the vapor from the mechanical vapor recompression, (e) a trim condenser which completes the condensing of the vapor/liquid mix of the reboiler, (f) a heat recovery circuit which condenses the rectifying column overheads and molecular sieve dry ethanol condenser and (g) a heat exchange to transfer the recovered heat of (f) to the first distillation stripping column reboiler feed.

Abstract: A method for converting methanol to gasoline boiling range hydrocarbons is disclosed. In an aspect the method includes feeding crude methanol from a methanol synthesis reactor to a methanol separation vessel to recover a methanol stream in a vapor phase; and without condensing the methanol stream, feeding the methanol stream in the vapor phase to a reactor containing a conversion catalyst for converting methanol to at least one of dimethyl ether or gasoline boiling range hydrocarbons.

Abstract: The invention relates to an esterification unit (150) and esterification process for producing crude methyl methacrylate (MMA) from methacrylamide (MAM), which enable particularly to improve the yield, meaning that the organics spent acids are low; and at the same time, providing crude MMA with rather good quality, meaning that MMA concentration in crude MMA is rather high and preferably from 50 wt % to 80 wt %. According to the invention, the esterification unit comprises esterification reactors (1, . . . , 5 (or 6) set up in a serial way so that there is a counter current flow between gaseous phase and liquid phase, the liquid phase flowing from first reactor (1) of the series to last reactor (5 (or 6)), and the gaseous phase flowing from reactor to first reactor (1).

Abstract: Process for copolymerizing ethylene and esters of vinyl alcohol in the presence of free-radical polymerization initiators at pressures in the range of from 110 MPa to 500 MPa and temperatures in the range of from 100° C. to 350° C. in a continuously operated polymerization apparatus comprising a polymerization reactor and one or more compressors, which compress the monomer mixture fed to the polymerization reactor to the polymerization pressure, wherein the monomer mixture is compressed by a sequence of compression stages in which the compressed gas mixture is cooled after each compression stage and the fraction of the monomer mixture, which is liquid after this cooling, is separated off and returned to the polymerization apparatus in liquid form, and wherein at least a part of the liquid fractions obtained after compressing the monomer mixture in the respective compression stage to a pressure of from 0.2 MPa to 10 MPa is purified before being returned to the polymerization process.

Abstract: A method for preparing methyl formate in which a raw material containing formaldehyde, methanol and/or dimethyl ether is introduced into a first reaction zone to come into contact with a catalyst A, and a component I is obtained by separation, the component I is introduced into a second reaction zone to come into contact with a catalyst B so as to obtain, by separation, methyl formate as a product, dimethyl ether that is returned to the first reaction zone and a component II that is returned to the second reaction zone, the catalysts have a long service life, the reaction conditions are mild, and the utilization rate of the raw material is high, thus enabling a continuous production for large-scale industrial application.

Abstract: Method for preparing methyl formate and coproducing dimethyl ether by reacting a formaldehyde and methanol raw material (molar ratio range of 1:4 to 1:0.05) in a First Reaction Region at ranges from 50° C. to 100° C. with Catalyst A resulting in post-reaction material separated into Constituent I. Reacting Constituent I in a Second Reaction Region at ranges from 50° C. to 200° C. and from 0.1 MPa to 10 MPa with Catalyst B resulting in post-reaction material, which is separated into methyl formate, dimethyl ether and Constituent II. At least 1% of dimethyl ether is product, and recycling the rest to the First Reaction Region. Constituent II is recycled to the Second Reaction Region. Each component is gaseous phase and/or liquid phase, independently. The method shows long catalyst life, mild reaction condition, high utilization ratio of raw materials, continuous production and large scale industrial application potential.

Abstract: A vehicle includes a vehicle platform and a natural gas fueled engine attached to the vehicle platform. The engine provides tractive power to at least one drive wheel. The vehicle includes an enclosure, attachable to the vehicle platform, to contain an array of natural gas storage vessels. The array of natural gas storage vessels is disposed completely within the enclosure. Each storage vessel of the array of natural gas storage vessels is in fluid communication with a single outlet port for selectively extracting the natural gas from the array of natural gas storage vessels. Each storage vessel of the array of natural gas storage vessels is in fluid communication with a single natural gas fill port.

Abstract: The present invention relates to a process for the recovery of acetic acid. The invention more particularly relates to a process comprising a stage of liquid/liquid extraction of an aqueous solution comprising acetic acid and to a stage of distillation of the extract obtained.

Abstract: The invention relates to a process for the preparation of aromatic amines in the liquid phase by catalytic hydrogenation of the corresponding nitroaromatic compounds in at least two reaction spaces connected in series, wherein at least one reaction space is operated isothermally and at least the reaction space connected downstream thereof is operated adiabatically, and in preferred embodiments the sudden adiabatic temperature change is used for monitoring the reaction.

Abstract: A working substance pairing comprising a working substance and an ionic liquid, its use in absorption heat pumps, absorption refrigeration machines and heat transformers and also corresponding apparatuses.

Abstract: Disclosed herein is a system comprising an evaporation unit comprising a first heat exchanger in fluid communication with a second heat exchanger; where the first heat exchanger is operative to heat an effluent stream comprising an amine solvent and/or amine byproducts and water and to discharge the effluent stream to the second heat exchanger; where the second heat exchanger is operative to convert the effluent stream into a distillate stream and a concentrate stream; and a reverse osmosis unit in fluid communication with the evaporation unit; where the reverse osmosis unit comprises a first reverse osmosis unit that is operative to receive the distillate stream and to separate water from byproducts of the amine solvent such that the water has a purity of greater than 95%, based on the weight of the distillate stream.

Abstract: A contaminant control system for an evaporative water purification process as deployed in a steam assisted gravity drainage process facility for in situ heavy oil recovery, The contaminant control system is specifically designed to simultaneously control silica, hardness and oil contaminant present in the evaporator feed water to prevent fouling of heat exchange surfaces and improve system reliability and can be applied to many evaporator designs available on the market.

Abstract: A closed loop contaminant control system for an evaporative water purification process at an oil recovery facility includes an evaporator having a water inlet, a distilled water discharge, and an oil and brine water discharge. A sump in the evaporator is divided by an oil skimming weir into a main sump and a blowdown sump, with the oil and brine water discharge located proximate the blowdown sump and the steam discharge located above the oil and brine discharge. A distillate tank receives distilled water from the evaporator and discharges the distilled water. The distillate tank has a level controller, other controllers provided for the system include a distilled water flow meter, a blowdown flow meter, a cycle controller, a total flow controller, a hardness controller, and a silica controller.

Abstract: The present invention relates to a method for preparing 1,3,5-trioxane using a distillation tower including a reactor, a distillation section, and an extraction section. Particularly, the present invention relates to a method for preparing 1,3,5-trioxane, in which the water phase separated from the stream discharged through the extraction unit of the reaction distillation tower is used in the process of extracting 1,3,5-trioxane.

Abstract: The present invention relates to a method for preparing 1,3,5-trioxane using a reaction distillation tower including a reactor and integrally formed distillation and extraction sections. Particularly, the present invention relates to a method for preparing 1,3,5-trioxane characterized in that the amount of formaldehyde discharged to the outside of the system is reduced, to thereby increase the yield of 1,3,5-trioxane by recirculating a portion of the water phase, which is discharged through the top of the reaction extraction tower, to the extraction section, and thus to the upper portion of the extractor supply stream which supplies extractant to the extraction section.

Abstract: A process for recovering butanol from a mixture of a water-immiscible organic extractant, water, butanol, and optionally a noncondensable gas, is provided. The butanol is selected from 1-butanol, isobutanol, and mixtures thereof An overhead stream from a first distillation column is decanted into two liquid phases. The wet butanol phase is returned to the first distillation column as reflux. A bottom stream from the first distillation column is refined in a second distillation column to obtain a second overhead stream and a second bottoms stream. The extractant may be C7 to C22 fatty alcohols, C7 to C22 fatty acids, esters of C7 to C22 fatty acids, C7 to C22 fatty aldehydes, and mixtures thereof.

Abstract: A water recovery process for a steam assisted gravity drainage system for a heavy oil recovery facility, the process comprising a flash drum and a flash drum heat exchanger/condenser, wherein the water recovery process receives hot water produced by a facility at a temperature above the water atmospheric boiling point and cools it to a temperature below the water atmospheric boiling point before transferring it to the remaining section of the water recovery process.

Abstract: Integration of an acid recovery system in the manufacturing of cellulose esters may include heat recovery from a carboxylic acid recovery distillation column by solvent extracting a weak acid stream to form a first overhead stream and a first bottoms stream; distilling the first overhead stream in a distillation column to form a second overhead stream and a second bottoms stream; sending at least a portion of the second overhead stream to a heat exchanger via a process inlet; sending a boiler feed water make up stream to the heat exchanger via a water inlet; and cooling the at least a portion of the second overhead stream in the heat exchanger, such that the at least a portion of second overhead stream exits the heat exchanger via a process outlet and the boiler feed water make up stream exits the heat exchanger via a water outlet.

Abstract: A process is provided for recovering components from a low boiler mixture which is obtained in the distillation of hydrogenation effluents from the preparation of polymethylols, by multistage distillation of the low boiler mixture having a tertiary amine, water, methanol, a polymethylol, a methylolalkanal, an alcohol and an alkanal with a methylene group in the alpha position to the carbonyl group. A first distillation stage involves separating the low boiler mixture into a higher-boiling, predominantly water-rich fraction and into a lower-boiling aqueous organic fraction having the tertiary amine. A second distillation stage involves separating the aqueous organic fraction from the first distillation stage into a predominantly amine-containing fraction and a further amine-depleted fraction. The tertiary amine is trimethylamine or triethylamine and the bottom temperature in the second distillation stage is at least 110° C.

Abstract: An apparatus for separating a hydrocarbon content from a material matrix composes the hydrocarbon content and a water content, the apparatus comprising: a material feeder arranged to feed material through a treatment chamber, the treatment chamber comprising a window which is substantially transparent to microwaves; a microwave emitter arranged in use to expose feed material in the treatment chamber to microwaves via the window in order to cause rapid heating of at least part of the water content of the matrix to form steam, so as to remove at least part of the hydrocarbon content from the matrix; wherein the material feeder and treatment chamber are arranged so that in use, the treatment chamber is substantially tilted with material/matrix.

Abstract: The present application concerns a process for the removal of hydrocarbons from an aqueous stream, which process may include conducting a phenol-containing water stream into a separation column, separating the phenol-containing water in the column using heat to form an overhead portion and a bottoms portion, and collecting the overhead portion as well as the bottoms portion. Further, the process may include adding an eluent to an aqueous stream, thereby forming an aqueous mixture, subsequently conducting the aqueous mixture into a separation vessel, wherein it is allowed to settle into two phases, which form a hydrocarbon stream and a phenol-containing water stream, subsequently collecting the hydrocarbon stream, and conducting the phenol-containing water stream to the separation column for further separation.

Abstract: A catalytic reaction-rectification integrated process and a catalytic reaction-rectification integrated column, and the specialized device of such process is provided. The reactants are preheated and mixed with catalysts, and then fed into a jet agitation reaction section located in the middle of the catalytic reaction-rectification integrated column from a feeding inlet. The jet agitation reaction section is a kettle-like reactor located in the middle of the catalytic reaction-rectification integrated column. After pressurized by a centrifugal pump, the reactant materials are admitted into a subsonic or transonic agitator located within the reaction section. The reactant materials are ejected into the jet agitation reaction section at high speed, to efficiently mix the solid and liquid phases in the reaction section and to reinforce heat and mass transfer efficiency during the reaction. The liquid reaction mixture is separated and purified directly in the catalytic reaction-rectification integrated column.

Abstract: Solvent regeneration to recover a polar hydrocarbon (HC) selective solvent substantially free of hydrocarbons (HCs) and other impurities from a solvent-rich stream containing selective solvent, heavy HCs, and polymeric materials (PMs) generated from reactions among thermally decomposed or oxidized solvent, heavy HCs, and additives is provided. A combination of displacement agent and associated co-displacement agent squeezes out the heavy HCs and PMs from the extractive solvent within a solvent clean-up zone. Simultaneously, a filter equipped with a magnetic field is positioned in a lean solvent circulation line to remove paramagnetic contaminants. The presence of the co-displacement agent significantly enhances the capability of the displacement agent in removing the heavy HCs and PMs from the extractive solvent.

Abstract: The invention provides systems and methods for the pre-concentration of a target molecule from feed solution comprising a low concentration of the target molecule.

Abstract: The invention relates to a method and an apparatus for dewatering mixture of ethanol and water. The method comprises steps for feeding mixture of ethanol and water (1) into an evaporator (2), evaporating said mixture of ethanol and water (1) and feeding a stream of vaporized mixture of ethanol and water (3) to a vapor recompression unit (4), pressurizing vaporized mixture of ethanol and water (3) in the vapor recompression unit (4) and feeding a stream of pressurized vaporized mixture of ethanol and water (5) to a membrane unit (6), and dividing said stream of pressurized mixture of ethanol and water (5) in to a stream of mixture of ethanol and water (8) and into a stream of dewatered mixture of ethanol and water (7).

Abstract: Provided is a method for recovering high-concentration and high-purity amine from amine-containing waste water generated from nuclear power plants and thermal power plants. The method includes: capturing amine and concentrating waste water using a cation exchange resin; separating amine from the concentrated amine-containing waste water; and carrying out further separation of amine via distillation. The method may be applied to treat amine, which causes an increase in biochemical oxygen demand (BOD) and total nitrogen concentration, drastically at the time of its generation from waste water of nuclear power plants and thermal power plants. In this manner, the method may prevent an increase in load of existing waste water treating plants and avoid a need for modifying the equipment in the existing plants.

Abstract: A process for purifying an aqueous stream from a Fischer-Tropsch reaction that includes feeding the aqueous stream to a system that includes a distillation column equipped with a partial condenser and a total condenser, at least partially condensing the vaporized stream leaving the head of the distillation column and collecting a first distillate in which in heavier by-products, totally condensing the remaining portion of the vaporized stream leaving the partial condenser and collecting a liquid stream which is returned to the distillation column as a reflux and removing a purified aqueous stream from the bottom of the distillation column.

Abstract: A method of dehydrating tolylenediamine which includes subjecting tolylenediamine having a water content of 5-40 wt. % to first-stage distillation at a vacuum of 13-101.3 kPa and subjecting the bottoms from the first-stage distillation to second-stage distillation at a vacuum lower than 13kPa.

Abstract: A process for removing trioxane from a use stream I of formaldehyde, trioxane and water, by a) providing a use stream I which comprises formaldehyde as the main component and trioxane and water as the secondary components, b) feeding the use stream I, a recycle stream V and a recycle stream VII which comprises formaldehyde as the main component and water and trioxane as the secondary components into a first distillation stage and distilling to obtain a stream II a steam III and formaldehyde as the and a steam X c) distilling the stream III, in a second distillation stage the pressure in the second distillation stage being from 0.

Abstract: An improved process for separation of liquid mixtures involves vapor stripping followed by mechanical compression of the vapor which is then exposed to a permeation membrane for separation of the compressed vapor. The apparatus for separating a liquid mixture of two or more solvents comprises components a stripping column, at least one over-head compressor and, thereafter, at least one selectively permeable membrane wherein the membrane separates the components of the vapor based on the different sorption and diffusion characteristics.

Abstract: A process and system for removing bound water from bio-oil by azeotropic distillation. The process includes combining a bound-water-containing bio-oil with an azeotrope agent and subjecting the resulting treated bio-oil to azeotropic distillation under reduced pressure. The azeotropic distillation removes a substantial portion of the bound water from the bio-oil, thus producing a water-depleted bio-oil that is less corrosive, more stable, and more readily miscible with hydrocarbons.

Abstract: A method for treating a wastewater containing oxygen-containing compound having a phenolic hydroxyl group or a carbonyl group, including a step of adding an alkali agent to the wastewater containing the oxygen-containing compound having a phenolic hydroxyl group or a carbonyl group to control a pH of the wastewater to 10 or more; and a step of separating a discharge in which the oxygen-containing compound having a phenolic hydroxyl group or a carbonyl group is concentrated through distillation of the wastewater to which the alkali agent has been added.

Abstract: Processes for the continuous fractional distillation of a mixture containing morpholine (MO), monoaminodiglycol (ADG), ammonia and water from a reaction of diethylene glycol (DEG) with ammonia, the process including: (i) separating off ammonia from the mixture at a top of a first distillation column K10; (ii) feeding a bottom fraction from K10 to a second distillation column K20, in which water and an organic product are separated off at the top at a temperature at the top in the range from 45 to 198° C. and a pressure in the range from 0.

Abstract: A dehydration method for removing water from a hydrolysis reaction mixture containing unreacted water generated when monochlorobenzene is hydrolyzed to produce phenol, the method for dehydrating the hydrolysis reaction mixture includes supplying a hydrolysis reaction mixture to a distillation tower, supplying a liquid containing monochlorobenzene to the tower top portion of the distillation tower, and removing the substantially whole amount of the water in the hydrolysis reaction mixture together with monochlorobenzene from the tower top portion by distillation.

Abstract: A treatment system for a watery material that includes: a dewatering tank in which liquefied matter of a material that is gaseous at a normal temperature and a normal pressure is contacted with the watery material and the watery material is separated into the resultant watery material and a liquid phase that contains an aqueous component from the watery material; an evaporator that vaporizes the material that is gaseous at a normal temperature and a normal pressure from the liquid phase; a separator that separates a gas of the material thus vaporized from effluent water; a condenser that condenses the gas into liquefied matter, two or more external heat sources selected from atmosphere, sewage, warm effluent water, and ground water; an external heat temperature detector that detects temperatures of external heats of the external heat sources; and an external heat supply destination controlling unit.

Abstract: Processes for the continuous fractional distillation of a mixture comprising morpholine (MO), monoaminodiglycol (ADG), ammonia and water from a reaction of diethylene glycol (DEG) with ammonia, the process comprising: (i) separating off ammonia from the mixture at a top of a first distillation column K10; (ii) feeding a bottom fraction from the first distillation column to a second distillation column K20, wherein water and an organic product are separated off at a top of the second distillation column at a top temperature of 45 to 198° C. and a pressure in the range from 0.1 to 15 bar; (iii) feeding a bottom fraction from the second distillation column to a third distillation column K30, wherein morpholine and an organic product having a boiling point of <140° C. (1.013 bar) are separated off at a point selected from a top and a side offtake of the third distillation column, and monoaminodiglycol and an organic product having a boiling point of >190° C. (1.

Abstract: Process for the continuous fractional distillation of mixtures including morpholine (MO), monoaminodiglycol (ADG), ammonia and water obtained by reaction of diethylene glycol (DEG) with ammonia, which includes separating off ammonia at the top of a first distillation column K10, feeding the bottoms from K10 to a second distillation column K20 in which water and organic products are separated off at the top at a temperature at the top in the range from 45 to 198° C. and a pressure in the range from 0.1 to 15 bar, feeding the bottoms from K20 to a third distillation column K30 in which MO and organic products having a boiling point of <140° C. (1.013 bar) are separated off at the top or at a side offtake and ADG and organic products having a boiling point of >190° C. (1.013 bar) are separated off at the bottom, feeding the MO including stream which is separated off at the top or at a side offtake of the column K30 to a fourth column K40 in which organic products having a boiling point of ?128° C. (1.

Abstract: The invention relates to a method and a device for the purification of an aqueous solution of an organic acid having a boiling point at atmospheric pressure of less than 450° C., which further has approximately 275 g carboxylate ions/l or less, preferably 250 g carboxylate ions/l or less, and preferably less than 1% by weight ionic impurities, calculated on the basis of the total solution. In particular, the invention relates to a method and a device for the continuous purification and concentration, on an industrial scale, of an aqueous solution of an organic acid having a boiling point at atmospheric pressure of less than 450° C. According to the method, this solution is subjected to two or more distillation steps, the first distillation step being carried out at a temperature of from 80° to 150° C. and a pressure of from 50 to 250 mbar, and the second distillation step being carried out at a temperature of from 80° to 200° C. and a pressure of from 0.01 to 50 mbar.

Abstract: Water is removed from oily water produced during operation of a separation column by withdrawing the oily water from the column during separation into an external separator where the oily water is separated into a water phase and an oily phase. The oily phase is then heated to a temperature effective to produce a density differential that drives the oily phase back into the operating column.

Abstract: A contaminant control system for an evaporative water purification process as deployed in a steam assisted gravity drainage process facility for in situ heavy oil recovery, The contaminant control system is specifically designed to simultaneously control silica, hardness and oil contaminant present in the evaporator feed water to prevent fouling of heat exchange surfaces and improve system reliability and can be applied to many evaporator designs available on the market.

Abstract: Aromatic amines are produced by catalytic hydrogenation of aromatic nitro compounds. The reaction mixture generated by this hydrogenation is then worked up by distillation in a manner which makes it possible to substantially free the amine of water with increased energy efficiency. Water free of amine and low boilers and the low boiling materials are also obtained.

Abstract: A natural gas dehydration system and method includes a contactor, a flash tank, and a still interconnected by a desiccant circulation system. A continuously fired reboiler is coupled to the still and the flash tank to burn the flash gas from the flash tank and heat the desiccant.

Abstract: A process and system for removing bound water from bio-oil by azeotropic distillation. The process comprises combining a bound-water-containing bio-oil with an azeotrope agent and subjecting the resulting treated bio-oil to azeotropic distillation under reduced pressure. The azeotropic distillation removes a substantial portion of the bound water from the bio-oil, thus producing a water-depleted bio-oil that is less corrosive, more stable, and more readily miscible with hydrocarbons.

Abstract: The present invention is directed to an enhanced process for separating dissolved and suspended solids from valuable or harmful liquids and more particularly to improving the operational aspects and separation efficiency of treating certain water miscible fluids including those used for oil and gas processing such as glycols, as well as automobile and aircraft fluids, that have become contaminated with dissolved and/or suspended solid matter.

Abstract: This invention is directed to methods for forming an olefin stream from a methanol stream. A lower grade methanol, such as chemical grade or crude methanol, can be used as feed to form the olefin stream. The process uses a relatively simple distillation type step to vaporize a portion of the methanol feed stream and send the resulting vapor stream to a reaction unit to form the olefin stream. In addition, the invention provides the ability to operate the downstream recovery units with reduced fouling or plugging due to the presence of fine solids components.

Abstract: Provided are a dehydrating system and a dehydrating method which achieve improvement in a membrane performance. The dehydrating system includes a first preheater 3a; multiple dehydrating apparatuses 1a, 1b and 1c which are connected in series downstream of the preheater and which are configured to remove water from an organic aqueous solution; and returning means 6 for returning a part of the organic aqueous solution having passed through one or more of the dehydrating apparatuses to the dehydrating apparatuses or the dehydrating apparatus upstream of the dehydrating apparatuses.

Abstract: A method of dehydrating tolylenediamine which includes subjecting tolylenediamine having a water content of 5-40 wt. % to first-stage distillation at a vacuum of 13-101.3 kPa and subjecting the bottoms from the first-stage distillation to second-stage distillation at a vacuum lower than 13 kPa.