CA1119193A - Continuous cyanoethylation process - Google Patents
Continuous cyanoethylation processInfo
- Publication number
- CA1119193A CA1119193A CA000329897A CA329897A CA1119193A CA 1119193 A CA1119193 A CA 1119193A CA 000329897 A CA000329897 A CA 000329897A CA 329897 A CA329897 A CA 329897A CA 1119193 A CA1119193 A CA 1119193A
- Authority
- CA
- Canada
- Prior art keywords
- cyanoethylation
- reaction
- acrylonitrile
- reaction zone
- process according
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C253/00—Preparation of carboxylic acid nitriles
- C07C253/30—Preparation of carboxylic acid nitriles by reactions not involving the formation of cyano groups
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C253/00—Preparation of carboxylic acid nitriles
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C253/00—Preparation of carboxylic acid nitriles
- C07C253/32—Separation; Purification; Stabilisation; Use of additives
- C07C253/34—Separation; Purification
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C255/00—Carboxylic acid nitriles
- C07C255/01—Carboxylic acid nitriles having cyano groups bound to acyclic carbon atoms
- C07C255/19—Carboxylic acid nitriles having cyano groups bound to acyclic carbon atoms containing cyano groups and carboxyl groups, other than cyano groups, bound to the same saturated acyclic carbon skeleton
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C255/00—Carboxylic acid nitriles
- C07C255/01—Carboxylic acid nitriles having cyano groups bound to acyclic carbon atoms
- C07C255/23—Carboxylic acid nitriles having cyano groups bound to acyclic carbon atoms containing cyano groups and carboxyl groups, other than cyano groups, bound to the same unsaturated acyclic carbon skeleton
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/50—Improvements relating to the production of bulk chemicals
- Y02P20/52—Improvements relating to the production of bulk chemicals using catalysts, e.g. selective catalysts
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
An improvement in a continuous homogeneous cyanoethyla-tion process involving the use of a relatively large amount of recycle, e.g., 50-90 wt.% of the reactor effluent, which is premixed with the fresh feed going to the reaction zone. The reaction zone is maintained at a cyanoethylation temperature.
High yields of cyanoethylated products are obtained. The process, e.g., has a yield in excess of 95 wt.% of 3,3'-ethylenedioxybis (propionitrile) from the reaction of ethylene glycol and acrylonitrile and the use of a catalyst, e.g., an aqueous alkali metal hydroxide.
An improvement in a continuous homogeneous cyanoethyla-tion process involving the use of a relatively large amount of recycle, e.g., 50-90 wt.% of the reactor effluent, which is premixed with the fresh feed going to the reaction zone. The reaction zone is maintained at a cyanoethylation temperature.
High yields of cyanoethylated products are obtained. The process, e.g., has a yield in excess of 95 wt.% of 3,3'-ethylenedioxybis (propionitrile) from the reaction of ethylene glycol and acrylonitrile and the use of a catalyst, e.g., an aqueous alkali metal hydroxide.
Description
CROSS REFERENCE TO RELATED APP$ICATION
The sub~ect matter of this application is rela~ed to Canadian patent application Serial No. 329,918 filed same date by the above-identified applicants. The title of the latter application is "High Selectivity Cyanoethylation Process."
BACKGROUND
This lnvention is directed to an impro~ement to a cyanoethyiation process. The process involved is continuous.
~ .
.. ... . . . . .. . .
11~9~93 Cyanoethylation refers to the reaction between acrylo-nitrile and a variety of compounds to yield ~ -substituted propionitrile derivatives. The compounds are characterized by their possession of a labile hydrogen atom. The latter is a hydrogen atom bonded to an electronegative atom or to an atom activated by strongly electronegative substituents.
Classes of compounds containing labile hydrogen include those having hydroxyl groups, e.g., water, alcohol~ and gly-cols. Cyanoethylation can be generalized by the following reaction formula:
The sub~ect matter of this application is rela~ed to Canadian patent application Serial No. 329,918 filed same date by the above-identified applicants. The title of the latter application is "High Selectivity Cyanoethylation Process."
BACKGROUND
This lnvention is directed to an impro~ement to a cyanoethyiation process. The process involved is continuous.
~ .
.. ... . . . . .. . .
11~9~93 Cyanoethylation refers to the reaction between acrylo-nitrile and a variety of compounds to yield ~ -substituted propionitrile derivatives. The compounds are characterized by their possession of a labile hydrogen atom. The latter is a hydrogen atom bonded to an electronegative atom or to an atom activated by strongly electronegative substituents.
Classes of compounds containing labile hydrogen include those having hydroxyl groups, e.g., water, alcohol~ and gly-cols. Cyanoethylation can be generalized by the following reaction formula:
2 ~HCN ~ RH ~ RCH2CH2CN
Cyanoethylation products are useful intermediates for the manufacture of plastics and fibers.
Cyanoethylation is used in the formation of a great variety of mono-and poly-functional nitriles, for examplessee -Encyclopedia of Chemical Technology, Kirk-Othmer, 2nd Edition, Volume 6, and Organic Reactions, R. Adams et al, Vol. 5, John Wiley and Sons, N.Y. 1949.
~or large scale production of ~ -substituted pro-pionitrile derivatives it is advantageous to operate thecyanoethylation reaction in a continuous process. However, this is difficult to do while obtaining economically high ! yields because ll) the cyanoethylation reaction is highly exothermic; l2) the acrylonitrile tends to polymerize when present in high concentrations; (3) the cyanoethylation reaction is readily reversible at certain conditions. ~o avoid the foregoing problems it is possible to add slowly the acrylonitr$1e to an excess amount of the compound containing the labile hydrogen atoms. But the latter is relatively ..
!
~119193 inefficient since long residence times are re~uired to attain a high level of conversion.
Overcoming the aforementioned problems is the present invention which is an improvement to a continuous cyanoethylation process. The improvement permits the cyano- _ ethylation to be carried out continuously in a controlled -manner and with high yields of ~-substituted propionitrile derivatives. The high yields are surprising since the cyanoethylation reaction is known to be readily reversible under typical operating conditions. The improvement also eaces the problem of heat removal. Further, the improvement reduces, if not eliminates, the need for an inert solvent.
SUMMARY OF THE INVENTION
In the continuous cyanoethylation process the improve-ment is that a relatively large portion of the reaction effluent is recycled back into the reaction zone. The amount of recycle effluent is in the range from about 50 wt. % to about 90 ~t. S.
~he recycle is mixed with the fresh feed to the reaction zone prior to it~s introduction into the reaction zone. Components o~ the fresh feed include acrylonitrile and a compound containing a labile hydrogen atom and a catalyst, if used. Generally the e~luent contains less than about 3 wt.% of unreacted acrylonitrile and more than about 90 wt. % of the ~-substituted propionitrile derivative. Temperature of the reaction zone is in the cyanoethyla-tion reaction temperature range. Commercially the temperature range is between from about 0C to about 100C. The system, i.e., the reactants and catalyst, if used, is of a homgeneous nature.
.
.. - . . , Thus, in accordance with the present teachings, an improvement is provided in a process for cyanoethylation of a compound which has a labile hydrogen atom selected from the group consisting of monohydric alcohol, polyhydric alcohol, water and phenols wherein the compound is contacted at a cyanoethylation temperature with acrylonitrile and a cyano-ethylation catalyst in a reaction zone to form a cyanoethylated product and byproduct and wherein the reaction-is accompanied by undesired production of by-products with resulting reduction in selectivity for the desired cyanoethylated product. The improvement which is provided comprises conducting a reaction in the presence of about 1 to 9 volumes of the cyanoethylated product in addition to that which is formed in situ by reaction of the compound and the acrylonitrile, whereby production of byproducts is reduced.
.' f~
~ 3a-.
BRIE~ DESCRI~TI~N OF THE DRAWING
The accompanying Figure is a schematic drawing of one embodiment of the improvement in the continuous cyano-ethylation process.
EMB~DINENTS ;
In the Figure the acrylonitrile feed (1) is introduced into reaction means ~10). Accompanying the feed acrylonitrile (1) is stream (6) which components are a compound containing a labile hydrogen (4), a catalyst (5), if uqed, and a:
recycle (2) which i~ a portion of the reactor effluent (8).
The balance of the reactor ef~luent 13) is processed to separate the desired ~ -substituted propionitrile derlvatives from any -~
unreacted acrylonitrile, by-products, reactant intermediates, and cataly~t, lf used.
Reaction means tlO) is designed to provide a residence t$me for the reactants, catalyst, if used, and product which results in a desired conversion. Means (10) also can contain ~ ;
means (not shown) for mixing the contacting materials. Means tlO) also can contain optional means (7) for cooling the cyano-ethylation reaction. Generally the residence time will range bet~een from about a quarter of an hour to about five to seven hour~. Another way of indicating residence time is the com-po~itlon of the effluent. Generally the effluent leaving the ~
cyanoethylation reaction zone contains less than 3 wt. % ~-unreacted acrylonitrile and preferably less than 1 wt. %.
Another measure of residence time is the amount of desired product in the effluent. Generally the effluent contains at least 90 wt. % of the desired product, i~e., the cyanoethylated , ". .
product, and preferably at least 95 wt. %.
The amount of recycle (2) iq between two limitations.
The upper limitation is that if the amount of recycle (2) is increased the selectivity decreases. The lower limitation is that if the amount of recycle ~2) is decreased the temperature at the reactton zone inlet increases and as a result the amount or coproducts, which are often unwanted, increases. The tempera-ture of recycle (2) can be modified by optional means (not shown). M~nor changes in the selectivity and/or temperature can occur for various reasons thus the decrease or increase Rhould be 9ubstantial. Commercial range of the amount of recycle ~2) ranges between from about 50 wt. ~ to about 90 wt. % of the effluent leaving means (10) and a preferred range i9 between from about 60 wt. % to about 80 wt. %.
The cyanoethylation process can also be described as follows. Acrylonitrile ~1) at the rate of 613 pounds per hour is in~ected into means (10). Just prior to the injection into meanS ~10), ethylene glycol (4), at a rate of 35a pounds per hour, into which i8 injected sodium hydroxide (5) at a rate of 29 pounds per hour, i8 in~ected into the acrylonitrile tl).
Also contacting the ethylene glycol and sodium hydroxide mixture is 2000 pounds of reactor effluent (2) and the resulting three component mixture contacts the acrylonitrile (1). The product mixture ~3), at a rate of 1000 pounds per hour is with-drawn from the system. The product mixture (3) is sent to purification means where the catalyst is neutralized and the desired product is ~eparated, e.g., by distillation. The neutralized and separated product consists of essentially
Cyanoethylation products are useful intermediates for the manufacture of plastics and fibers.
Cyanoethylation is used in the formation of a great variety of mono-and poly-functional nitriles, for examplessee -Encyclopedia of Chemical Technology, Kirk-Othmer, 2nd Edition, Volume 6, and Organic Reactions, R. Adams et al, Vol. 5, John Wiley and Sons, N.Y. 1949.
~or large scale production of ~ -substituted pro-pionitrile derivatives it is advantageous to operate thecyanoethylation reaction in a continuous process. However, this is difficult to do while obtaining economically high ! yields because ll) the cyanoethylation reaction is highly exothermic; l2) the acrylonitrile tends to polymerize when present in high concentrations; (3) the cyanoethylation reaction is readily reversible at certain conditions. ~o avoid the foregoing problems it is possible to add slowly the acrylonitr$1e to an excess amount of the compound containing the labile hydrogen atoms. But the latter is relatively ..
!
~119193 inefficient since long residence times are re~uired to attain a high level of conversion.
Overcoming the aforementioned problems is the present invention which is an improvement to a continuous cyanoethylation process. The improvement permits the cyano- _ ethylation to be carried out continuously in a controlled -manner and with high yields of ~-substituted propionitrile derivatives. The high yields are surprising since the cyanoethylation reaction is known to be readily reversible under typical operating conditions. The improvement also eaces the problem of heat removal. Further, the improvement reduces, if not eliminates, the need for an inert solvent.
SUMMARY OF THE INVENTION
In the continuous cyanoethylation process the improve-ment is that a relatively large portion of the reaction effluent is recycled back into the reaction zone. The amount of recycle effluent is in the range from about 50 wt. % to about 90 ~t. S.
~he recycle is mixed with the fresh feed to the reaction zone prior to it~s introduction into the reaction zone. Components o~ the fresh feed include acrylonitrile and a compound containing a labile hydrogen atom and a catalyst, if used. Generally the e~luent contains less than about 3 wt.% of unreacted acrylonitrile and more than about 90 wt. % of the ~-substituted propionitrile derivative. Temperature of the reaction zone is in the cyanoethyla-tion reaction temperature range. Commercially the temperature range is between from about 0C to about 100C. The system, i.e., the reactants and catalyst, if used, is of a homgeneous nature.
.
.. - . . , Thus, in accordance with the present teachings, an improvement is provided in a process for cyanoethylation of a compound which has a labile hydrogen atom selected from the group consisting of monohydric alcohol, polyhydric alcohol, water and phenols wherein the compound is contacted at a cyanoethylation temperature with acrylonitrile and a cyano-ethylation catalyst in a reaction zone to form a cyanoethylated product and byproduct and wherein the reaction-is accompanied by undesired production of by-products with resulting reduction in selectivity for the desired cyanoethylated product. The improvement which is provided comprises conducting a reaction in the presence of about 1 to 9 volumes of the cyanoethylated product in addition to that which is formed in situ by reaction of the compound and the acrylonitrile, whereby production of byproducts is reduced.
.' f~
~ 3a-.
BRIE~ DESCRI~TI~N OF THE DRAWING
The accompanying Figure is a schematic drawing of one embodiment of the improvement in the continuous cyano-ethylation process.
EMB~DINENTS ;
In the Figure the acrylonitrile feed (1) is introduced into reaction means ~10). Accompanying the feed acrylonitrile (1) is stream (6) which components are a compound containing a labile hydrogen (4), a catalyst (5), if uqed, and a:
recycle (2) which i~ a portion of the reactor effluent (8).
The balance of the reactor ef~luent 13) is processed to separate the desired ~ -substituted propionitrile derlvatives from any -~
unreacted acrylonitrile, by-products, reactant intermediates, and cataly~t, lf used.
Reaction means tlO) is designed to provide a residence t$me for the reactants, catalyst, if used, and product which results in a desired conversion. Means (10) also can contain ~ ;
means (not shown) for mixing the contacting materials. Means tlO) also can contain optional means (7) for cooling the cyano-ethylation reaction. Generally the residence time will range bet~een from about a quarter of an hour to about five to seven hour~. Another way of indicating residence time is the com-po~itlon of the effluent. Generally the effluent leaving the ~
cyanoethylation reaction zone contains less than 3 wt. % ~-unreacted acrylonitrile and preferably less than 1 wt. %.
Another measure of residence time is the amount of desired product in the effluent. Generally the effluent contains at least 90 wt. % of the desired product, i~e., the cyanoethylated , ". .
product, and preferably at least 95 wt. %.
The amount of recycle (2) iq between two limitations.
The upper limitation is that if the amount of recycle (2) is increased the selectivity decreases. The lower limitation is that if the amount of recycle ~2) is decreased the temperature at the reactton zone inlet increases and as a result the amount or coproducts, which are often unwanted, increases. The tempera-ture of recycle (2) can be modified by optional means (not shown). M~nor changes in the selectivity and/or temperature can occur for various reasons thus the decrease or increase Rhould be 9ubstantial. Commercial range of the amount of recycle ~2) ranges between from about 50 wt. ~ to about 90 wt. % of the effluent leaving means (10) and a preferred range i9 between from about 60 wt. % to about 80 wt. %.
The cyanoethylation process can also be described as follows. Acrylonitrile ~1) at the rate of 613 pounds per hour is in~ected into means (10). Just prior to the injection into meanS ~10), ethylene glycol (4), at a rate of 35a pounds per hour, into which i8 injected sodium hydroxide (5) at a rate of 29 pounds per hour, i8 in~ected into the acrylonitrile tl).
Also contacting the ethylene glycol and sodium hydroxide mixture is 2000 pounds of reactor effluent (2) and the resulting three component mixture contacts the acrylonitrile (1). The product mixture ~3), at a rate of 1000 pounds per hour is with-drawn from the system. The product mixture (3) is sent to purification means where the catalyst is neutralized and the desired product is ~eparated, e.g., by distillation. The neutralized and separated product consists of essentially
3,3'-ethylenedioxybis(propionitrile), e.g., in excess of 95 wt. %. The yield of the products is in excess of 95 wt. % based on the ethylene ~lycol (41 and acrylonitrile charged to the ~119~3 reaction means (lO~.
Thus the improvement to a continuous homogeneous cyanoethylation process in which the temperature of the reaction zone, which is equivalent to the aforementioned means ~lO), is maintained within the cyanoethylation reaction temperature range comprises that the amount of reaction effluent recycling to the cyanoethylation reaction zone is in the range between where the selectivity aecreaQes if the amount of the effluent recycling is increased, i.e., above about 90 wt. %, and where the temperature at the reaction zone inlet increases if the amount of the effluent recycling is decreased, i.e., below about 50 wt. ~.
Generally the cyanoethylation reaction temperature in a range between from about 0C to about 100C. At a lower temperature the reaction rate is probably too slow whereas a higher temperature promotes undesirable Qide reàctions. The preferred temperature range for the reaction is in a range between from about 20C to about 50C.
The improvement further comprises that a portion of the reaction effluent, which is the effluent from the reaction zone which i8 not processed to separate the desired ~-sub-stituted propionitrile derivatives, contacts a compound containing the labile hydrogen atom and the resulting mixture of the two contact~ acrylonitrile. The latter is fresh acrylonitrile -which is feed to reaction zone. The improvement further ; comprises that the resulting mixture of the recycling reactor effluent and the compound containing the labile hydrogen atom - 1119~93 contacts a basic catal~st pr~or to contacting t~e acrylonitrile entering the reaction zone.
As is known a strongly basic catalyst is often used for the cyanoethylation reaction; however, it does depend on which particular compound containing a labile hydrogen atom is used. Thus ~or example a strongly basic catalyst is used wf th an al~phatic monohydric or polyhydric alcohol whereas no catalyst is used if the compound is a primary or secondary aliphatic amine. ~urthermore, as is known, acids act as cata-. la lysts under certain circums~ances~ The quantity of catalystrequired is small. In general 1-5wt% of catalyst based on the weight of acrylonitrile is satis~actory. Useful catalyst include alkali metals, oxides of alkali metals, and hydroxides of alkali metals. Often the hydroxide of the alkali metals, e.g., KOH, and NaOH, is a concentrated aqueous solution.
As stated hereto~ore, one of the reactants in the cyanoethylation reaction is a compound containfng a labile hydrogen atom. Thus the reaction can be effected with hydroxyl compounds, e.g., water, alcohols polyalcohols, and phenols, with thiols, e.g., aliphatic mercaptans, with nitrogen compounds, e.g., amines, amides and many other materials. Included in the polyalcohols are ethylene glycol and the like.
The following examples, along with a comparative run, ~llustrate the improvement.
EXAMPLES
This example is a batch experiment with a simulated recycle which showed that the cyanoethylation reaction can be controlled and that a high yield o~ desired product can be achieved.
.
9~93 To a 2000 ml. flask $itted wit~ a st~rrer, reflux condensor and an addition funnel and immersed in an ice water bath wa~ added 248 g. of et~ylene glycol and 20 g. of 40%
aqueous NaOH. The stirrer was started and the 424 g~ of acrylonitrile was added from t~e funnel over a period of about 15 minutes. The temperature remained ~n the range of 25-35C
during the add~t~on o~ the acrylonitrile. The stirring was continued for one additional hour after which 170 g, of the reaction mixture was withdrawn from the gla~k and neutralized by contacting with 70 g~ of a sulfonic acid resin.
The withdrawn mixture contained more than 95 wt. ~ of 3,3'-ethy-lenedioxy-bis(propionitrile), and essentially no acrylonitrile.
The following were rapidly added to the foregoing flask containing the remaining reaction mixture and in the following order: Ethylene glycol, 62 g.~ aqueous (40%) NaOH, 5 g.s and acrylonitrile, 106 g~ The temperature remained at about 30C during the addition and the stirring was continued for 90 minutes. Afterward the contents of the flask were neutralized with sulfonic acid resin as described above. The composition of thi~ second batch was virtually identical to the first withdrawn mixture in that it contained more than 95 wt. % of the propionitrile derivative and essentially no acrylonitrile.
In contrast the following illustrates the problems, particularly of a rapid exotherm, that can develop during the cyanoethylation. To a 500 ml. Morton flask fitted with a stirrer, reflux condensor and an additional funnel and Lmmersed in an ice water bath wa3 added 62 g. of ethylene glycol and 5 g. of 40% aqueous NaOH. To the resulting mixture was rapidly added 106 g. of acrylonitrile from the funnel and then t~e stirrer was turned on. Within 5 minutes, the temperature rose to 60C and then rapidly to 120C at which tempera~ure the contents erupted from the flask.
In another run the cyanoethylation reaction was carried out continuously in a 1/4 x 84 inch stainless steel tubular reactor immersed in a circulating bath regulated at 30C. Ethylene~ioxybis(propioni~rile)simulating product recycled from the reactor outlet, was pumped at 0.247 ml/min. to a mixing-tee. There it merged with ethylene glycol containing 7 wt. % of 40% aqueous sodium hydroxide that wa~ pumped at the rate of 0.0285 ml/min. The mixed stream was led thru a 1/4 x 20 inch tube to a second tee and acrylonitrile was pumped at 0.0741 ml. /min., i.e., 1.09 mole/mole glycol.
This mixed ~tream entered the reactor directly and upon exiting was collected in a graduated receiver from which Yample cuts were withdrawn periodically. The samples were neutralizsd by shaking with a sulfonic acid ion-exchange resin and then analyzed by gas chromatography.
A sample taken after 3-hours contained 93 wt. %
dinitrile, 1 wt. % mononitrile and 1 wt. % byproducts. The balance was water from the catalyst and exces~ acrylonitrile. This analysis corresponds to 97 wt. % selectivity to useful product.
Another sample removed after 4 hours was virtually identical indicating that steady state operation had been achieved.
Another continuous reaction was performed in the same manner as described above except that the acrylonitrile was pumped at 0.0667 mi./min. Samples taken after 3 and 4 hours of operation were analyzed as before. They contained 95-96 wt. % dinitrile, 0.5 wt. % mononitrile, 0.5-1.0 wt. %
other byproduct~ and 3-4 wt. % water plus residual acrylonitrile.
The corresponding selectivity wa~ 97-98 wt. %.
_ g _ The use of other compounds containing a labile hydrogen, e.g., ammonia, an amine, water, ethanol, propanol, 2-ethyl-1-hexanol, and the like, will yield analogous results.
-- 10 .--, .. ,,., .. .... .. ,.. ., . .. ~; .. . .. , ~
Thus the improvement to a continuous homogeneous cyanoethylation process in which the temperature of the reaction zone, which is equivalent to the aforementioned means ~lO), is maintained within the cyanoethylation reaction temperature range comprises that the amount of reaction effluent recycling to the cyanoethylation reaction zone is in the range between where the selectivity aecreaQes if the amount of the effluent recycling is increased, i.e., above about 90 wt. %, and where the temperature at the reaction zone inlet increases if the amount of the effluent recycling is decreased, i.e., below about 50 wt. ~.
Generally the cyanoethylation reaction temperature in a range between from about 0C to about 100C. At a lower temperature the reaction rate is probably too slow whereas a higher temperature promotes undesirable Qide reàctions. The preferred temperature range for the reaction is in a range between from about 20C to about 50C.
The improvement further comprises that a portion of the reaction effluent, which is the effluent from the reaction zone which i8 not processed to separate the desired ~-sub-stituted propionitrile derivatives, contacts a compound containing the labile hydrogen atom and the resulting mixture of the two contact~ acrylonitrile. The latter is fresh acrylonitrile -which is feed to reaction zone. The improvement further ; comprises that the resulting mixture of the recycling reactor effluent and the compound containing the labile hydrogen atom - 1119~93 contacts a basic catal~st pr~or to contacting t~e acrylonitrile entering the reaction zone.
As is known a strongly basic catalyst is often used for the cyanoethylation reaction; however, it does depend on which particular compound containing a labile hydrogen atom is used. Thus ~or example a strongly basic catalyst is used wf th an al~phatic monohydric or polyhydric alcohol whereas no catalyst is used if the compound is a primary or secondary aliphatic amine. ~urthermore, as is known, acids act as cata-. la lysts under certain circums~ances~ The quantity of catalystrequired is small. In general 1-5wt% of catalyst based on the weight of acrylonitrile is satis~actory. Useful catalyst include alkali metals, oxides of alkali metals, and hydroxides of alkali metals. Often the hydroxide of the alkali metals, e.g., KOH, and NaOH, is a concentrated aqueous solution.
As stated hereto~ore, one of the reactants in the cyanoethylation reaction is a compound containfng a labile hydrogen atom. Thus the reaction can be effected with hydroxyl compounds, e.g., water, alcohols polyalcohols, and phenols, with thiols, e.g., aliphatic mercaptans, with nitrogen compounds, e.g., amines, amides and many other materials. Included in the polyalcohols are ethylene glycol and the like.
The following examples, along with a comparative run, ~llustrate the improvement.
EXAMPLES
This example is a batch experiment with a simulated recycle which showed that the cyanoethylation reaction can be controlled and that a high yield o~ desired product can be achieved.
.
9~93 To a 2000 ml. flask $itted wit~ a st~rrer, reflux condensor and an addition funnel and immersed in an ice water bath wa~ added 248 g. of et~ylene glycol and 20 g. of 40%
aqueous NaOH. The stirrer was started and the 424 g~ of acrylonitrile was added from t~e funnel over a period of about 15 minutes. The temperature remained ~n the range of 25-35C
during the add~t~on o~ the acrylonitrile. The stirring was continued for one additional hour after which 170 g, of the reaction mixture was withdrawn from the gla~k and neutralized by contacting with 70 g~ of a sulfonic acid resin.
The withdrawn mixture contained more than 95 wt. ~ of 3,3'-ethy-lenedioxy-bis(propionitrile), and essentially no acrylonitrile.
The following were rapidly added to the foregoing flask containing the remaining reaction mixture and in the following order: Ethylene glycol, 62 g.~ aqueous (40%) NaOH, 5 g.s and acrylonitrile, 106 g~ The temperature remained at about 30C during the addition and the stirring was continued for 90 minutes. Afterward the contents of the flask were neutralized with sulfonic acid resin as described above. The composition of thi~ second batch was virtually identical to the first withdrawn mixture in that it contained more than 95 wt. % of the propionitrile derivative and essentially no acrylonitrile.
In contrast the following illustrates the problems, particularly of a rapid exotherm, that can develop during the cyanoethylation. To a 500 ml. Morton flask fitted with a stirrer, reflux condensor and an additional funnel and Lmmersed in an ice water bath wa3 added 62 g. of ethylene glycol and 5 g. of 40% aqueous NaOH. To the resulting mixture was rapidly added 106 g. of acrylonitrile from the funnel and then t~e stirrer was turned on. Within 5 minutes, the temperature rose to 60C and then rapidly to 120C at which tempera~ure the contents erupted from the flask.
In another run the cyanoethylation reaction was carried out continuously in a 1/4 x 84 inch stainless steel tubular reactor immersed in a circulating bath regulated at 30C. Ethylene~ioxybis(propioni~rile)simulating product recycled from the reactor outlet, was pumped at 0.247 ml/min. to a mixing-tee. There it merged with ethylene glycol containing 7 wt. % of 40% aqueous sodium hydroxide that wa~ pumped at the rate of 0.0285 ml/min. The mixed stream was led thru a 1/4 x 20 inch tube to a second tee and acrylonitrile was pumped at 0.0741 ml. /min., i.e., 1.09 mole/mole glycol.
This mixed ~tream entered the reactor directly and upon exiting was collected in a graduated receiver from which Yample cuts were withdrawn periodically. The samples were neutralizsd by shaking with a sulfonic acid ion-exchange resin and then analyzed by gas chromatography.
A sample taken after 3-hours contained 93 wt. %
dinitrile, 1 wt. % mononitrile and 1 wt. % byproducts. The balance was water from the catalyst and exces~ acrylonitrile. This analysis corresponds to 97 wt. % selectivity to useful product.
Another sample removed after 4 hours was virtually identical indicating that steady state operation had been achieved.
Another continuous reaction was performed in the same manner as described above except that the acrylonitrile was pumped at 0.0667 mi./min. Samples taken after 3 and 4 hours of operation were analyzed as before. They contained 95-96 wt. % dinitrile, 0.5 wt. % mononitrile, 0.5-1.0 wt. %
other byproduct~ and 3-4 wt. % water plus residual acrylonitrile.
The corresponding selectivity wa~ 97-98 wt. %.
_ g _ The use of other compounds containing a labile hydrogen, e.g., ammonia, an amine, water, ethanol, propanol, 2-ethyl-1-hexanol, and the like, will yield analogous results.
-- 10 .--, .. ,,., .. .... .. ,.. ., . .. ~; .. . .. , ~
Claims (11)
1. In a process for cyanoethylation of a compound having a labile hydrogen atom selected from the group consisting of monohydric alcohol, polyhydric alcohol, water and phenols which comprises contacting said compound at a cyanoethylation temperature with acrylonitrile and a cyanoethylation catalyst in a reaction zone to form a cyanoethylated product and byproducts wherein the reaction is accompanied by undesired production of byproducts with resulting reduction in selectivity for the desired cyanoethylated product, the improvement which comprises conduct-ing the reaction in the presence of about 1 to 9 volumes of the cyano-ethylated product in addition to that which is formed in situ by reaction of the compound and said acrylonitrile, whereby production of byproducts is reduced.
2. Process according to Claim 1 wherein a portion of effluent from the reaction zone is recycled to the reaction zone to provide the cyanoethylated product.
3. Process according to Claim 1 wherein the compound is an aliphatic polyhydric alcohol, and the desired cyanoethylation product is a dinitrile.
4. Process according to Claim 1 wherein the temperature in the reaction zone is maintained in the range between about 0°C to about 100°C.
5. Process according to Claim 1 wherein the cyanoethylation catalyst is an aqueous solution of a hydroxide of an alkali metal.
6. Process according to Claim 1 wherein the reactor effluent contains more than about 90 wt.% of the cyanoethylation product.
7. Process according to Claim 6 wherein the reactor effluent further contains less than about 3 wt.% of unreacted acrylonitrile.
8. Process according to Claim 7 wherein the temperature in the reaction zone is maintained in the range between from about 0°C to about 100°C and the cyanoethylation catalyst is an aqueous solution of a hydroxide of an alkali metal.
9. Process according to Claim 8 wherein the cyanoethylated product is 3,3-ethylene dioxybis(propionitrile).
10. In a process for cyanoethylation of ethylene glycol which comprises contacting the ethylene glycol, at a cyanoethylation tem-perature with acrylonitrile and a cyanoethylation catalyst in a reaction zone to form 3,3'-ethylene dioxybis(propionitrile), a monoadduct of acrylonitrile and ethylene glycol and by-products, wherein the reaction is accompanied by undesired production of by-products with resulting re-duction in selectivity for 3,3'-ethylene dioxybis(propionitrile), in addition to that which is formed in situ by reaction of the ethylene glycol and the acrylonitrile, whereby the production of the by-products is reduced.
11. In a process for cyanoethylation of an aliphatic polyhydric alcohol which comprises contacting the aliphatic polyhydric alcohol at a cyanoethylation temperature with acrylonitrile and a cyanoethylation catalyst in a reaction zone to form a polynitrile, other adducts of acrylonitrile and aliphatic polyhydric alcohol by-products, wherein the reaction is accompanied by undesired production of by-products with re-sulting reduction in selectivity for the polynitrile the improvement which comprises conducting the reaction in the presence of about 1 to 9 volumes of the polynitrile in addition to that which is formed in situ by reaction of the aliphatic polyhydric alcohol and the acrylonitrile, whereby the production of the by-products is reduced.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US91639378A | 1978-06-16 | 1978-06-16 | |
| US916,393 | 1978-06-16 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1119193A true CA1119193A (en) | 1982-03-02 |
Family
ID=25437200
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000329897A Expired CA1119193A (en) | 1978-06-16 | 1979-06-15 | Continuous cyanoethylation process |
Country Status (6)
| Country | Link |
|---|---|
| JP (1) | JPS554380A (en) |
| CA (1) | CA1119193A (en) |
| DE (1) | DE2924133A1 (en) |
| FR (1) | FR2428626A1 (en) |
| GB (1) | GB2023143B (en) |
| IT (1) | IT1121805B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20140018567A1 (en) * | 2011-03-18 | 2014-01-16 | Lg Chem, Ltd. | Method for preparing dinitrile compound |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0135725B1 (en) * | 1983-08-02 | 1989-03-08 | Tosoh Corporation | Process for producing polyamines |
| JPS60102154A (en) * | 1983-11-07 | 1985-06-06 | フエジエル メグイエイ ガボナフオルガルミ エス マロミパリ バララツト | Production of starchy product |
| US5075507A (en) * | 1988-08-01 | 1991-12-24 | Air Products And Chemicals, Inc. | Process for the preparation of bis(aminopropyl)aliphatic glycols |
| US5081305A (en) * | 1988-10-13 | 1992-01-14 | Air Products And Chemicals, Inc. | Process for the preparation of bis(aminopropoxy)alkanes |
| JP2013075837A (en) * | 2011-09-29 | 2013-04-25 | Fujifilm Corp | Manufacturing method for nitrile compound |
| US11989421B2 (en) | 2021-08-19 | 2024-05-21 | Micron Technology, Inc. | Adjustable data protection scheme using artificial intelligence |
| US11698858B2 (en) | 2021-08-19 | 2023-07-11 | Micron Technology, Inc. | Prediction based garbage collection |
| CN114632489A (en) * | 2022-05-18 | 2022-06-17 | 山东海科新源材料科技股份有限公司 | Method and device for synthesizing ethylene glycol bis (propionitrile) ether crude product |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1054685A (en) * | 1963-04-20 | |||
| JPS5710869B2 (en) * | 1973-10-05 | 1982-03-01 |
-
1979
- 1979-06-15 JP JP7476579A patent/JPS554380A/en active Granted
- 1979-06-15 IT IT23644/79A patent/IT1121805B/en active
- 1979-06-15 DE DE19792924133 patent/DE2924133A1/en active Granted
- 1979-06-15 CA CA000329897A patent/CA1119193A/en not_active Expired
- 1979-06-15 GB GB7921012A patent/GB2023143B/en not_active Expired
- 1979-06-18 FR FR7915517A patent/FR2428626A1/en active Granted
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20140018567A1 (en) * | 2011-03-18 | 2014-01-16 | Lg Chem, Ltd. | Method for preparing dinitrile compound |
| US9394242B2 (en) * | 2011-03-18 | 2016-07-19 | Lg Chem, Ltd. | Method for preparing dinitrile compound |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2023143B (en) | 1982-11-03 |
| DE2924133C2 (en) | 1989-08-24 |
| FR2428626A1 (en) | 1980-01-11 |
| JPS638937B2 (en) | 1988-02-25 |
| FR2428626B3 (en) | 1982-05-21 |
| JPS554380A (en) | 1980-01-12 |
| DE2924133A1 (en) | 1979-12-20 |
| IT7923644A0 (en) | 1979-06-15 |
| GB2023143A (en) | 1979-12-28 |
| IT1121805B (en) | 1986-04-23 |
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