CA1047536A - Treatment of adiponitrile with molecular sieves - Google Patents
Treatment of adiponitrile with molecular sievesInfo
- Publication number
- CA1047536A CA1047536A CA234,357A CA234357A CA1047536A CA 1047536 A CA1047536 A CA 1047536A CA 234357 A CA234357 A CA 234357A CA 1047536 A CA1047536 A CA 1047536A
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- Prior art keywords
- adiponitrile
- molecular sieve
- ammonia
- type
- water
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C255/00—Carboxylic acid nitriles
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- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A process for reducing the amount of basic impurities, especially N-heterocyclic compounds, in adiponitrile is dis-closed. The process comprises treating adiponitrile with a Type X or Type Y molecular sieve. Type Y molecular sieves are preferred. The molecular sieve may be in the polyvalent cation, ammonia or hydrogen form. The adiponitrile may be treated in the presence or absence of water. The process is particularly useful in the purification of adiponitrile manufactured from adipic acid and ammonia.
A process for reducing the amount of basic impurities, especially N-heterocyclic compounds, in adiponitrile is dis-closed. The process comprises treating adiponitrile with a Type X or Type Y molecular sieve. Type Y molecular sieves are preferred. The molecular sieve may be in the polyvalent cation, ammonia or hydrogen form. The adiponitrile may be treated in the presence or absence of water. The process is particularly useful in the purification of adiponitrile manufactured from adipic acid and ammonia.
Description
~047s36 The present invention relates to the treatment of adiponitrile with molecular sieves and in particular to a pro-cess for reducing the amount o~ basic impurities in crude adipo-nitrile in which crude adiponitrile is treated with molecular sieves.
One of the more important uses of adiponitrile at the present time is in the manu~acture of hexamethylene diamine.
This diamine may be used as a detergent, as an emulsifying agent or, in particular, as an intermediate in the manufacture of poly-mers. A catalytic hydrogenation reaction is usually èmployedto convert adiponitrile to hexamethylene diamine.
mere are æeveral method8 for synthesizing adipo-nitrile. In particular, adiponitrile may be obtained by re-acting adipic acid wlth ammonia in the presence of a dehy-drating catalyst, for example, by the techniques disclosed in U. S. Patent 2,200,734 of Arnold and Lazier which issued May 14, 1940 and in U.S. Patent 2,273,633 of M. L. A. Fluchaire which issued February 17, 1942. Adiponitrile obtained from adipic acid contains impurities, some of which boil at temp-eratures close to the boiling point of adiponitrile. 2-Cyano-cyclopentylideneimine, hereinafter sometimes referred to as CPI, is an example of such an impurity. Close boiling impuri-ties frequently cannot be removed efficiently in industrial scale distillation columnsO Impurities in the adiponitrile may lead to impurities in subsequent derivatives, in particular in hexamethylene diamine, that are difficult to remove. Failure to remove these latter impurities may result in inferior and variable properties, especially in polymers manufactured using such impure hexamethylene diamine. Techniques for the purif-ication of adiponitrile are known in the art. For example,adiponitrile may be treated with a solid acidic catalyst in the ~04~7536 presence of water and at a temperature of at least 140C to remove 2-cyanocyclopentylideneimine ~rom the adiponitrile.
The s~lid acidic catalystæ may be silica-alumina catalysts, cr~stalline aluminosilicates, boron phosphate or titania-alumina.
Such treatment is described in Canadian Patent 912,036 of B. J.
Kershaw which issued October 10, 1972.
Adiponitrile obtained from the reaction of adipic acid with ammonia may also contain impurities in the form of cyclic Pm~nes, especially N-heterocyclic compounds. Examples of such impurities are 2-methyl-4-amino-5,6-trimethylene pyr-imidine, hereinafter sometimes referred to as MAP, 2-amino-3,4,-5,6 bis(trimethylene) pyridine, hereinafter sometimes referred to as ABP, and 2-cyclopentyl-4-amino-5,6-trimethylene pyrimidine, hereinafter sometimes re~erred to as VAP. Such N-heterocyclic compounds may cause problems in the hydrogenation of adipo-nitrile to hexamethylene diamine or in the subsequent purific-ation of the hexamethylene diamine.
It has now been ~ound that basic impurities, es-pecially N-heterocyclic compounds, may be removed from crude adiponitrile by treating the adiponitrile with a Type X or a Type Y molecular sieve, such molecular sieves being discussed hereinafter.
Accordingly, the present invention provides a pro-cess for reducing the amount of basic impurities in crude adiponitrile, said process comprising the steps of treating adiponitrile with a molecular sieve selected from the group consisting of Type X and Type Y, and mixtures thereof, at a temperature in the range 25-250C, said molecular sieve being in a form selected from the group consisting of 3o polyvalent cation, ammonia, and hydrogen; and separating adiponitrile, provided that ta) when the molecular sieve is 10~7536 in the ammonia form, or (b) when the adiponitrile is treated with the molecular sieve in the absence of water, the temperature is in the range of 100-250 C.
In a preferred embodiment of the process of the present invent;ion the adiponitrile is manufactured from adipic acid and ammonia.
In a further embodiment the molecular sieve is a Type Y molecular sieve.
Molecular sieves, which are also referred to as zeo-lites, are aluminosilicates having a framework structure with cavities capable of being occupied by large ions and water molecules. Molecular sieve~ may be used as catalysts, as ion exchange materials or as absorbent materials. There are many types of molecular sieves and their properties depend on, for example, the ~ramework structure of the aluminosilicate and the resultant pore size, the silica/alumina ratio and the type of cation in the structure. Examples of molecular sieves of rela-tively large pore size are Types X and Y, both of which are structurally related to the mineral faujasite, (Na2, Ca, Mg)60 (A12)60 (Sio2)l32 26H2- Type Y has a higher silica/alumina ratio than Type X. Type X molecular sieves have been disclosed in U. S. Patent 2,882,244 of R. M. Mllton which issued April 14, 1959 and Type Y molecular sieves have been disclosed in U. S.
3,130,007 of D. ~. Breck which iæsued April 21, 1964. The basic crystal structures of Type X and Type Y molecular sieves may be identified by X-ray diffraction. Type X and Type Y molecular sieves are available in many forms, e.g., with univalent cations, for example sodium, ammonia, hydrogen, and with multivalent cations, for example calcium, magnesium, nickel. As is dis-closed in the aforementioned U.S. Patent 3,130,007 molecular sieves are generally synthesized in the sodium form and other ln~7s36 types are derived therefrom. Molecular sieves are discussed in greater detail in "Molecular Sieve Zeolites: Trendsetters in Heterogeneous Catalysis" by P. E. Pickert et al in Chemical ~ngineering, July 29, 1968, pages 2-11 and in bulletins on LINDE*
molecular sieves obtainable from the Linde Division of Union Carbide Corporation, for example, bulletins entitled "A Report on Molecular Sieve Catalysts" and "A Report on Molecular Sieve Catalyst SK-500". The molecular sieves of the present invention are Type X and Type Y molecular sieves, and sieves derived there-from~ especially such sieves in the polyvalent cation, hydrogenand ammonia forms. Type Y molecular sieves are preferred. In preferred embodiments of the process of the present invention the molecular sieves are in the hydrogen form, or are convertible thereto in situ. The conversion of molecular sieves to such form~ is knownO
In the process of the present invention crude adipo-nitrile i8 treated with a molecular sieve. In the process the adiponitrile may be treated by contacting the adiponitrile and molecular sieve in a continuous process or in a batch process, the former being preferred. Preferably, the adiponitrile is pa~sed through a fixed bed of the molecular sieve. In a pre-ferred embodiment the adiponitrile is adiponitrile manufactured fro~ adlpic acid and ammonia.
While the adiponitrile treated by the process of the present invention is described as "crude adiponitrile", the adipo-nitrile being treated is preferably adiponitrile that has been subjected to partial purification, e.g., by distillation.
me treatment of crude adiponitrile according to the process of the present invention may be carried out in the presence or absence of water. In the presence of water the adipo-nitrile is treated with the molecular sieve in the polyvalent cation or hydrogen forms at temperatures in the range 25-250C
*denotes trade mark 1~47536 or with the molecular sieve in the ammonia form at temperatures in the range of 100-250C. Higher temperatures are operable but at such temperatures degradation and~or hydrolysis of the adipc,nitrile may occur. Treatment may occur at lower temper-atures at low rates. Furthermore, if the adiponitrile contains
One of the more important uses of adiponitrile at the present time is in the manu~acture of hexamethylene diamine.
This diamine may be used as a detergent, as an emulsifying agent or, in particular, as an intermediate in the manufacture of poly-mers. A catalytic hydrogenation reaction is usually èmployedto convert adiponitrile to hexamethylene diamine.
mere are æeveral method8 for synthesizing adipo-nitrile. In particular, adiponitrile may be obtained by re-acting adipic acid wlth ammonia in the presence of a dehy-drating catalyst, for example, by the techniques disclosed in U. S. Patent 2,200,734 of Arnold and Lazier which issued May 14, 1940 and in U.S. Patent 2,273,633 of M. L. A. Fluchaire which issued February 17, 1942. Adiponitrile obtained from adipic acid contains impurities, some of which boil at temp-eratures close to the boiling point of adiponitrile. 2-Cyano-cyclopentylideneimine, hereinafter sometimes referred to as CPI, is an example of such an impurity. Close boiling impuri-ties frequently cannot be removed efficiently in industrial scale distillation columnsO Impurities in the adiponitrile may lead to impurities in subsequent derivatives, in particular in hexamethylene diamine, that are difficult to remove. Failure to remove these latter impurities may result in inferior and variable properties, especially in polymers manufactured using such impure hexamethylene diamine. Techniques for the purif-ication of adiponitrile are known in the art. For example,adiponitrile may be treated with a solid acidic catalyst in the ~04~7536 presence of water and at a temperature of at least 140C to remove 2-cyanocyclopentylideneimine ~rom the adiponitrile.
The s~lid acidic catalystæ may be silica-alumina catalysts, cr~stalline aluminosilicates, boron phosphate or titania-alumina.
Such treatment is described in Canadian Patent 912,036 of B. J.
Kershaw which issued October 10, 1972.
Adiponitrile obtained from the reaction of adipic acid with ammonia may also contain impurities in the form of cyclic Pm~nes, especially N-heterocyclic compounds. Examples of such impurities are 2-methyl-4-amino-5,6-trimethylene pyr-imidine, hereinafter sometimes referred to as MAP, 2-amino-3,4,-5,6 bis(trimethylene) pyridine, hereinafter sometimes referred to as ABP, and 2-cyclopentyl-4-amino-5,6-trimethylene pyrimidine, hereinafter sometimes re~erred to as VAP. Such N-heterocyclic compounds may cause problems in the hydrogenation of adipo-nitrile to hexamethylene diamine or in the subsequent purific-ation of the hexamethylene diamine.
It has now been ~ound that basic impurities, es-pecially N-heterocyclic compounds, may be removed from crude adiponitrile by treating the adiponitrile with a Type X or a Type Y molecular sieve, such molecular sieves being discussed hereinafter.
Accordingly, the present invention provides a pro-cess for reducing the amount of basic impurities in crude adiponitrile, said process comprising the steps of treating adiponitrile with a molecular sieve selected from the group consisting of Type X and Type Y, and mixtures thereof, at a temperature in the range 25-250C, said molecular sieve being in a form selected from the group consisting of 3o polyvalent cation, ammonia, and hydrogen; and separating adiponitrile, provided that ta) when the molecular sieve is 10~7536 in the ammonia form, or (b) when the adiponitrile is treated with the molecular sieve in the absence of water, the temperature is in the range of 100-250 C.
In a preferred embodiment of the process of the present invent;ion the adiponitrile is manufactured from adipic acid and ammonia.
In a further embodiment the molecular sieve is a Type Y molecular sieve.
Molecular sieves, which are also referred to as zeo-lites, are aluminosilicates having a framework structure with cavities capable of being occupied by large ions and water molecules. Molecular sieve~ may be used as catalysts, as ion exchange materials or as absorbent materials. There are many types of molecular sieves and their properties depend on, for example, the ~ramework structure of the aluminosilicate and the resultant pore size, the silica/alumina ratio and the type of cation in the structure. Examples of molecular sieves of rela-tively large pore size are Types X and Y, both of which are structurally related to the mineral faujasite, (Na2, Ca, Mg)60 (A12)60 (Sio2)l32 26H2- Type Y has a higher silica/alumina ratio than Type X. Type X molecular sieves have been disclosed in U. S. Patent 2,882,244 of R. M. Mllton which issued April 14, 1959 and Type Y molecular sieves have been disclosed in U. S.
3,130,007 of D. ~. Breck which iæsued April 21, 1964. The basic crystal structures of Type X and Type Y molecular sieves may be identified by X-ray diffraction. Type X and Type Y molecular sieves are available in many forms, e.g., with univalent cations, for example sodium, ammonia, hydrogen, and with multivalent cations, for example calcium, magnesium, nickel. As is dis-closed in the aforementioned U.S. Patent 3,130,007 molecular sieves are generally synthesized in the sodium form and other ln~7s36 types are derived therefrom. Molecular sieves are discussed in greater detail in "Molecular Sieve Zeolites: Trendsetters in Heterogeneous Catalysis" by P. E. Pickert et al in Chemical ~ngineering, July 29, 1968, pages 2-11 and in bulletins on LINDE*
molecular sieves obtainable from the Linde Division of Union Carbide Corporation, for example, bulletins entitled "A Report on Molecular Sieve Catalysts" and "A Report on Molecular Sieve Catalyst SK-500". The molecular sieves of the present invention are Type X and Type Y molecular sieves, and sieves derived there-from~ especially such sieves in the polyvalent cation, hydrogenand ammonia forms. Type Y molecular sieves are preferred. In preferred embodiments of the process of the present invention the molecular sieves are in the hydrogen form, or are convertible thereto in situ. The conversion of molecular sieves to such form~ is knownO
In the process of the present invention crude adipo-nitrile i8 treated with a molecular sieve. In the process the adiponitrile may be treated by contacting the adiponitrile and molecular sieve in a continuous process or in a batch process, the former being preferred. Preferably, the adiponitrile is pa~sed through a fixed bed of the molecular sieve. In a pre-ferred embodiment the adiponitrile is adiponitrile manufactured fro~ adlpic acid and ammonia.
While the adiponitrile treated by the process of the present invention is described as "crude adiponitrile", the adipo-nitrile being treated is preferably adiponitrile that has been subjected to partial purification, e.g., by distillation.
me treatment of crude adiponitrile according to the process of the present invention may be carried out in the presence or absence of water. In the presence of water the adipo-nitrile is treated with the molecular sieve in the polyvalent cation or hydrogen forms at temperatures in the range 25-250C
*denotes trade mark 1~47536 or with the molecular sieve in the ammonia form at temperatures in the range of 100-250C. Higher temperatures are operable but at such temperatures degradation and~or hydrolysis of the adipc,nitrile may occur. Treatment may occur at lower temper-atures at low rates. Furthermore, if the adiponitrile contains
2-cyanocyclopentylideneimine and the temperature is at least 140 C the 2-cyanocyclopentylideneimine may be hydrolyzed thereby permitting a simultaneous reduction in the amount of 2-cyanocyclopentylideneimine and o~ basic impurities in the adiponitrile. In the absence of water the adiponitrile is treated with the molecular sieve at temperatures in the range of 100-250 C.
Higher temperatures are operable but degradation of the adipo-nitrile may occur. At lower temperatures purification may occur at slow rates.
The pressure used in the process of the present in-vention is not critical. The pressure will depend primarily on other process variables, for example temperature and the water content o~ the adiponitrile.
The water content of the adiponitrile may be varied from 0% to a ratio of water to adiponitrile of about 2:1 on a weight basis, the temperature at which treatment is carried out being selected accordingly. The upper limit of the level o~
water i8 determined primarily by practical considerations.
In an embodiment the adiponitrile contains at least 1% by weight of water.
In a preferred embodiment of the process of the present invention the adiponitrile is substantially free of ammonia. If ammonia is present it is pre~erable to operate the process at temperatures in the high end of the temperature range, for example, at least 180C.
~1 the process of the present invention ~m~nes es-pecially the aforementioned cyclic amines are removed from the adiponitrile by retention on the molecular sieve. After a ~ 0~7536 period of time it may become desirable to remove said amines from the molecular sieve and thereby re~enerate the molecular sieve for further use. A number of techniques for regeneration of molecular sieves are known. For example, the molecular sieve may be treated with a solution o~ ammonia at temperatures of fro~n ambient to about 70 C followed by a heat treatment of the molecular sieve to remove ammonia. Alternatively the molecular sieve may be heated under an inert gas, treated with steam at high temperatures or treated with a base of higher af~inity ~or the molecular sieve that the amines ~ollowed by treatment to remove the base~
Adiponitrile purified by the process described herein is particularly useful in the manufacture of hexamethylene diamine using an iron catalyst as is disclosed in Canadian patent appli-cation 234 356 of B. J. Kershaw filed on the same date as the present application.
The process of the present invention is illustrated by the following examples. The adiponitrile used in the ex-amples had been manufactured from adipic acid and ammonia.
EXAMPLE I
In the runs of this example, and in Examples II-V
hereinafter, three different samples of adiponitrile were used. The compositions o~ the adiponitrile are given in Table I.
With reference to the runs in Table II, adiponitrile was mixed with water, where applicable, and molecular sieve powder in th~ quantities specified. The mixture was stirred for the time specified. The molecular sieve used in all runs was a Type Y molecular sieve in the polyvalent cation ~orm obtained ~rom the Linde Division of Union Carbide Corporation under the trade mark SK-500. The molecular sieve was filtered off before analysisO Details of the runs and the results ob-tained are given in Table II.
EXAMPLE II
Using the procedure of Example I adiponitrile was treated with a Type Y molecular sieve ln the ammonia form ob-tained from the Linde Div~sion of Union Carbide Corporation under the trade mark SK-41. Details of the runs and the results ob-taine~ are given in Table III.
EXAMPLE III
To show that the organic amines may be displaced from the molecular sieve, 10 ml of adiponitrile #1 was mixed with 1 g of SK-500 (polyvalent cation form) and 1 ml o~ water. The mix-ture wa~ stirred for 20 minutes at room temperature and then the SK-500 was filtered off. The SK-500 so obtained was extracted with aqueous ammonia using a soxhlet extraction apparatus.
The results were aæ follows:
Component Removal from Recovery from SK-500 _ Adiponitrile (%) molecular sieve (%) EXAMPLE IV
To show that the molecular sieve may be regenerated, 50 ml of adiponitrile #2 was mixed with 3 ml water and 0.5 g of SK-500 molecular sieve (polyvalent cation form) and stirred for 30 minutes at room temperature. The SK-500 was filtered off. The amines were displaced from the SK-500 so obtained by the method of Example III. The filtrate (filtrate #l) was analyzed. The SK-500 was dried at 90C for 4 hours and then mixed with 50 ml of adiponitrile #2 and 3 ml of water. mis mixture was stirred for 2 hours at room temperature. me SK-500 was filtered off and the filtrate (filtrate #2) analyzed.
~04'~536 The results were as follows:
Filtrate Removal of A~ines (%)*
MAP ABP
#1 58 57 ~2 19 17 *Remo~al of amines on weight percent basis from the adipo-nitrile as indicated by analysis of filtrate.
EXAMPI,E V
To show regeneration of the molecular sieve at a temperature higher than that of Example IV, 200 ml of adipo-nitrile ~1 was mixed with 12 ml of water and 2 g of SK-500 lecular sieve (polyvalent cation form) and stirred for 45 m~nutes at room temperature. The molecular sieve was fil-tered off and the filtrate (filtrate #l) was analyzed. The molecular sieve was treated with aqueous ammonia and then heated at 260 C under a flow of nitrogen for about 12 hours.
0.8 g of the molecular sieve so obtained was mixed with 40 ml of adiponitrile #1 and 2.4 ml of water and stirred for 15 min-utes. The mnlecular sieve was filtered off and the filtrate (filtrate #2) was analyzed.
The results were as follows:
~iltrate Removal of Amines (%) MAP ABP
#1 7 65 #2 82 82 EXAMPLE VI
A sample of a Type X molecular sieve obtained from the Linde Division of Union Carbide Corporation under the trade mark 13X was heated for one hour at 250 C in an atmosphere of nitrogen. 0.25 g of the molecular sieve was then mixed with 25 ml of crude adiponitrile and stirred for 10 minutes at 110 C~ The crude adiponitrile contained approximately 300 ppm o~ MAP and 700 ppm of ABP. The treatment with the molecular sieve reduced the MAP and ABP in the adiponitrlle by 48% and 65% respectively.
EXAMPLE VII
To 50 ml of a crude adiponitrile containing approx-imately 420 ppm o~ MAP and 750 ppm of ABP were added 3 ml of water and 1 g of SK-500 molecular sieve. me mixture was stirred ~or 15 minutes at room temperature, filtered and the adiponitrile was analyzed. The MAP and ABP in the adiponitrile had been reduced by 85% and 96% respectively.
The procedure was repeated using Silica Alumina 979, an amorphous silica alumina obtained ~rom W. R. Grace, instead of SE-500 molecular sieve. Only 17% of the MAP was removed from the adiponitrile, thereby showing the importance o~ using a Type X or Type Y molecular sieve for the removal of amines from crude adiponitrile.
TABLE I
Component* Adiponitrile ~1 Adiponitrile #2 Adiponitrile #3 MAP O.042 0.042 0.03 ABP 0.075 0.075 -7 VAP o 075 ~PI 0.35 0.38 0.12 -cyanovaleric acid 1.0 ca 0,0 ca 0.0 -cyanovaleramide 0.5 0.3 ca 0.2 adipimide o.6 ca 0.0 0 N.B. All analyses expressed as percentages on a weight/volume basis, remaining component essentially adiponitrile.
* MAP _ 2-methyl-4-amino-5,6-trimethylene pyrimidine ABP _ 2-amino-3,4,5,6-bis(trimethylene) pyridine VAP _ 2-cyclopentyl-4-amino-5,6-trimethylene pyrimidine CPI - 2-cyanocyclopentylideneimine TABLE II
Run No. I II III IV V**
Reaction Mixture Adiponitrile (ml)50 50 100 100 type #l #2 #3 #3 Water (ml) 3 3 o Molecular Sieve (g) Reaction Conditions Temperature (C)ambient ambient 105 103 178 Time (min.) 30 30 50 3 15 Analysis MAP before 0.042 0.042 0.03 0.030. oo6 a~ter 0.020 0. oo6 o. oo4 o. oo6 o. 007 ABP before 0.075 0.075 0.07 0.07 o.oo6 after NA* o. 003 o. Ols o. oo6 o. oo6 CPI before 0.35 0.38 0.12 0.12 0.10 after NA NA 0.12 0.10 0.07 *NA = not available ** Run V was made as follows: at the completion of ~un IV a sample wa~ taken for anal~sis and the remainder of the reaction mixture wa~ treated according to the conditions speci~ied in Run V. The treated material in Run IV and V was of lighter colour than the adiponitrile before treatment.
~04753~i TABLE III
Run No. VI VII VIII* IX**
Reaction Mixture Adiponitrile (ml) lO0 100 - 94 type #3 #3 - #l Watet (ml) 0 1 - 6 Molecular Sieve (g) Reaction Conditions Temperature (C) llO 104 173 120 Time (min) 40 30 15 3 Analysis MAP before 0.03 0.03 0.02 0.042 a~ter 0.008 0.02 0.002 0.013 ABP before 0.07 0.07 0.05 .75 after 0.04 0.05 0.01 0.030 CPI before 0.12 0.12 0.11 0.35 a~ter 0.12 0.11 0.02 0.05 * Run VIII relates to Run VII in the same way as Run V relateæ
to Run IV.
** The SK-41 molecular æieve was heated to convert the sieve to the hydrogen form prior to comm~ncing this run. After treat-ment the adiponitrile was dehydrated by heating to 190C be~ore analysi~.
Higher temperatures are operable but degradation of the adipo-nitrile may occur. At lower temperatures purification may occur at slow rates.
The pressure used in the process of the present in-vention is not critical. The pressure will depend primarily on other process variables, for example temperature and the water content o~ the adiponitrile.
The water content of the adiponitrile may be varied from 0% to a ratio of water to adiponitrile of about 2:1 on a weight basis, the temperature at which treatment is carried out being selected accordingly. The upper limit of the level o~
water i8 determined primarily by practical considerations.
In an embodiment the adiponitrile contains at least 1% by weight of water.
In a preferred embodiment of the process of the present invention the adiponitrile is substantially free of ammonia. If ammonia is present it is pre~erable to operate the process at temperatures in the high end of the temperature range, for example, at least 180C.
~1 the process of the present invention ~m~nes es-pecially the aforementioned cyclic amines are removed from the adiponitrile by retention on the molecular sieve. After a ~ 0~7536 period of time it may become desirable to remove said amines from the molecular sieve and thereby re~enerate the molecular sieve for further use. A number of techniques for regeneration of molecular sieves are known. For example, the molecular sieve may be treated with a solution o~ ammonia at temperatures of fro~n ambient to about 70 C followed by a heat treatment of the molecular sieve to remove ammonia. Alternatively the molecular sieve may be heated under an inert gas, treated with steam at high temperatures or treated with a base of higher af~inity ~or the molecular sieve that the amines ~ollowed by treatment to remove the base~
Adiponitrile purified by the process described herein is particularly useful in the manufacture of hexamethylene diamine using an iron catalyst as is disclosed in Canadian patent appli-cation 234 356 of B. J. Kershaw filed on the same date as the present application.
The process of the present invention is illustrated by the following examples. The adiponitrile used in the ex-amples had been manufactured from adipic acid and ammonia.
EXAMPLE I
In the runs of this example, and in Examples II-V
hereinafter, three different samples of adiponitrile were used. The compositions o~ the adiponitrile are given in Table I.
With reference to the runs in Table II, adiponitrile was mixed with water, where applicable, and molecular sieve powder in th~ quantities specified. The mixture was stirred for the time specified. The molecular sieve used in all runs was a Type Y molecular sieve in the polyvalent cation ~orm obtained ~rom the Linde Division of Union Carbide Corporation under the trade mark SK-500. The molecular sieve was filtered off before analysisO Details of the runs and the results ob-tained are given in Table II.
EXAMPLE II
Using the procedure of Example I adiponitrile was treated with a Type Y molecular sieve ln the ammonia form ob-tained from the Linde Div~sion of Union Carbide Corporation under the trade mark SK-41. Details of the runs and the results ob-taine~ are given in Table III.
EXAMPLE III
To show that the organic amines may be displaced from the molecular sieve, 10 ml of adiponitrile #1 was mixed with 1 g of SK-500 (polyvalent cation form) and 1 ml o~ water. The mix-ture wa~ stirred for 20 minutes at room temperature and then the SK-500 was filtered off. The SK-500 so obtained was extracted with aqueous ammonia using a soxhlet extraction apparatus.
The results were aæ follows:
Component Removal from Recovery from SK-500 _ Adiponitrile (%) molecular sieve (%) EXAMPLE IV
To show that the molecular sieve may be regenerated, 50 ml of adiponitrile #2 was mixed with 3 ml water and 0.5 g of SK-500 molecular sieve (polyvalent cation form) and stirred for 30 minutes at room temperature. The SK-500 was filtered off. The amines were displaced from the SK-500 so obtained by the method of Example III. The filtrate (filtrate #l) was analyzed. The SK-500 was dried at 90C for 4 hours and then mixed with 50 ml of adiponitrile #2 and 3 ml of water. mis mixture was stirred for 2 hours at room temperature. me SK-500 was filtered off and the filtrate (filtrate #2) analyzed.
~04'~536 The results were as follows:
Filtrate Removal of A~ines (%)*
MAP ABP
#1 58 57 ~2 19 17 *Remo~al of amines on weight percent basis from the adipo-nitrile as indicated by analysis of filtrate.
EXAMPI,E V
To show regeneration of the molecular sieve at a temperature higher than that of Example IV, 200 ml of adipo-nitrile ~1 was mixed with 12 ml of water and 2 g of SK-500 lecular sieve (polyvalent cation form) and stirred for 45 m~nutes at room temperature. The molecular sieve was fil-tered off and the filtrate (filtrate #l) was analyzed. The molecular sieve was treated with aqueous ammonia and then heated at 260 C under a flow of nitrogen for about 12 hours.
0.8 g of the molecular sieve so obtained was mixed with 40 ml of adiponitrile #1 and 2.4 ml of water and stirred for 15 min-utes. The mnlecular sieve was filtered off and the filtrate (filtrate #2) was analyzed.
The results were as follows:
~iltrate Removal of Amines (%) MAP ABP
#1 7 65 #2 82 82 EXAMPLE VI
A sample of a Type X molecular sieve obtained from the Linde Division of Union Carbide Corporation under the trade mark 13X was heated for one hour at 250 C in an atmosphere of nitrogen. 0.25 g of the molecular sieve was then mixed with 25 ml of crude adiponitrile and stirred for 10 minutes at 110 C~ The crude adiponitrile contained approximately 300 ppm o~ MAP and 700 ppm of ABP. The treatment with the molecular sieve reduced the MAP and ABP in the adiponitrlle by 48% and 65% respectively.
EXAMPLE VII
To 50 ml of a crude adiponitrile containing approx-imately 420 ppm o~ MAP and 750 ppm of ABP were added 3 ml of water and 1 g of SK-500 molecular sieve. me mixture was stirred ~or 15 minutes at room temperature, filtered and the adiponitrile was analyzed. The MAP and ABP in the adiponitrile had been reduced by 85% and 96% respectively.
The procedure was repeated using Silica Alumina 979, an amorphous silica alumina obtained ~rom W. R. Grace, instead of SE-500 molecular sieve. Only 17% of the MAP was removed from the adiponitrile, thereby showing the importance o~ using a Type X or Type Y molecular sieve for the removal of amines from crude adiponitrile.
TABLE I
Component* Adiponitrile ~1 Adiponitrile #2 Adiponitrile #3 MAP O.042 0.042 0.03 ABP 0.075 0.075 -7 VAP o 075 ~PI 0.35 0.38 0.12 -cyanovaleric acid 1.0 ca 0,0 ca 0.0 -cyanovaleramide 0.5 0.3 ca 0.2 adipimide o.6 ca 0.0 0 N.B. All analyses expressed as percentages on a weight/volume basis, remaining component essentially adiponitrile.
* MAP _ 2-methyl-4-amino-5,6-trimethylene pyrimidine ABP _ 2-amino-3,4,5,6-bis(trimethylene) pyridine VAP _ 2-cyclopentyl-4-amino-5,6-trimethylene pyrimidine CPI - 2-cyanocyclopentylideneimine TABLE II
Run No. I II III IV V**
Reaction Mixture Adiponitrile (ml)50 50 100 100 type #l #2 #3 #3 Water (ml) 3 3 o Molecular Sieve (g) Reaction Conditions Temperature (C)ambient ambient 105 103 178 Time (min.) 30 30 50 3 15 Analysis MAP before 0.042 0.042 0.03 0.030. oo6 a~ter 0.020 0. oo6 o. oo4 o. oo6 o. 007 ABP before 0.075 0.075 0.07 0.07 o.oo6 after NA* o. 003 o. Ols o. oo6 o. oo6 CPI before 0.35 0.38 0.12 0.12 0.10 after NA NA 0.12 0.10 0.07 *NA = not available ** Run V was made as follows: at the completion of ~un IV a sample wa~ taken for anal~sis and the remainder of the reaction mixture wa~ treated according to the conditions speci~ied in Run V. The treated material in Run IV and V was of lighter colour than the adiponitrile before treatment.
~04753~i TABLE III
Run No. VI VII VIII* IX**
Reaction Mixture Adiponitrile (ml) lO0 100 - 94 type #3 #3 - #l Watet (ml) 0 1 - 6 Molecular Sieve (g) Reaction Conditions Temperature (C) llO 104 173 120 Time (min) 40 30 15 3 Analysis MAP before 0.03 0.03 0.02 0.042 a~ter 0.008 0.02 0.002 0.013 ABP before 0.07 0.07 0.05 .75 after 0.04 0.05 0.01 0.030 CPI before 0.12 0.12 0.11 0.35 a~ter 0.12 0.11 0.02 0.05 * Run VIII relates to Run VII in the same way as Run V relateæ
to Run IV.
** The SK-41 molecular æieve was heated to convert the sieve to the hydrogen form prior to comm~ncing this run. After treat-ment the adiponitrile was dehydrated by heating to 190C be~ore analysi~.
Claims (10)
1. A process for reducing the amount of basic impuri-ties in crude adiponitrile, said process comprising the steps of treating adiponitrile with a molecular sieve selected from the group consisting of Type X and Type Y, and mixtures thereof, at a temperature in the range 25-250°C, said molecular sieve being in a form selected from the group consisting of polyvalent cation, ammonia, and hydrogen; and separating adiponitrile, provided that (a) when the adiponitrile is treated with the molecular sieve in the presence of water the temperature is in the range of 25-120°C, and that (b) when the adiponitrile is treated with the molecular sieve in the absence of water the temperature is in the range of 100-250°C and provided futher than when the molecular sieve is in the ammonia form the temp-erature is at least 100°C.
2. The process of Claim 1 in which the adiponitrile is adiponitrile manufactured from adipic acid and ammonia.
3. The process of Claim 2 in which the adiponitrile is substantially free of ammonia.
4. The process of Claim 3 in which the molecular sieve is a Type Y molecular sieve.
5. The process of Claim 4 in which the adiponitrile is contacted with the molecular sieve in the presence of water, the temperature being in the range of 25-120°C.
6. The process of Claim 5 in which the ratio of water to adiponitrile is not greater than 2:1, on a weight basis.
7, The process of Claim 4 in which the adiponitrile is treated with the molecular sieve substantially in the absence of water, the temperature being in the range of 100-250°C.
8. The process of any one of Claim 1, Claim 6 and Claim 7 in which the molecular sieve is in the polyvalent cation form.
9. The process of any one of Claim 1, Claim 6 and Claim 7 in which the molecular sieve is in the hydrogen form.
10. The process of any one of Claim 1, Claim 6 and Claim 7 in which the crude adiponitrile has been subjected to distillation prior to treatment with the molecular sieve.
Priority Applications (9)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA234,357A CA1047536A (en) | 1975-08-26 | 1975-08-26 | Treatment of adiponitrile with molecular sieves |
| IT2584376A IT1065070B (en) | 1975-08-26 | 1976-07-29 | PROCESS FOR THE PRODUCTION OF HEXAMETHYLENE DIAMINE |
| GB2643877A GB1539437A (en) | 1975-08-26 | 1976-08-17 | Process for purifying adiponitrile |
| GB3427076A GB1539435A (en) | 1975-08-26 | 1976-08-17 | Process for the manufacture of hexamethylene diamine |
| FR7625712A FR2322127A1 (en) | 1975-08-26 | 1976-08-25 | PERFECTED PROCESS FOR THE PRODUCTION OF HEXAMETHYLENE DIAMINE FROM CRUDE ADIPONITRILE |
| DE19762638510 DE2638510A1 (en) | 1975-08-26 | 1976-08-26 | IMPROVED PROCESS FOR THE PREPARATION OF HEXAMETHYLENEDIAMINE |
| FR7706940A FR2334664A1 (en) | 1975-08-26 | 1977-03-09 | METHOD FOR REDUCING THE QUANTITY OF N-HETEROCYCLIC AMINE IN CRUDE ADIPONITRILE |
| US05/858,661 US4146555A (en) | 1975-08-26 | 1977-12-08 | Process for purifying adiponitrile |
| US05/858,663 US4147717A (en) | 1975-08-26 | 1977-12-08 | Process for purifying adiponitrile |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA234,357A CA1047536A (en) | 1975-08-26 | 1975-08-26 | Treatment of adiponitrile with molecular sieves |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1047536A true CA1047536A (en) | 1979-01-30 |
Family
ID=4103915
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA234,357A Expired CA1047536A (en) | 1975-08-26 | 1975-08-26 | Treatment of adiponitrile with molecular sieves |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1047536A (en) |
-
1975
- 1975-08-26 CA CA234,357A patent/CA1047536A/en not_active Expired
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