U.S. patent application number 10/489838 was filed with the patent office on 2004-12-23 for method of producing nitrile compounds.
Invention is credited to Basset, Jean-Marie, Chauvin, Yves, Galland, Jean-Christophe, Niccolai, Gerald, Valerio, Christine, Vallee, Christophe.
Application Number | 20040260112 10/489838 |
Document ID | / |
Family ID | 8867383 |
Filed Date | 2004-12-23 |
United States Patent
Application |
20040260112 |
Kind Code |
A1 |
Basset, Jean-Marie ; et
al. |
December 23, 2004 |
Method of producing nitrile compounds
Abstract
The present invention relates to the manufacture of nitrile
compounds from unsaturated organic compounds by reaction with
hydrogen cyanide. It relates more particularly to the manufacture
of nitrile compounds of use in the synthesis of adiponitrile, an
important chemical intermediate in the manufacture of major
chemical compounds, such as hexamethylenediamine and
.epsilon.-caprolactam. The invention provides a process for the
manufacture of organic compounds comprising at least one nitrile
functional group by carrying out a hydrocyanation reaction between
hydrogen cyanide and an organic compound comprising at least one
ethylenic unsaturation. This reaction is carried out in the
presence of a catalytic system comprising a metal element chosen
from the group consisting of nickel, platinum and palladium and an
organophosphorus ligand, the reaction medium additionally
comprising an ionic liquid in the liquid state at least at the
temperature at which the hydrocyanation reaction is carried
out.
Inventors: |
Basset, Jean-Marie; (Caluire
Et Cuire, FR) ; Chauvin, Yves; (Tours, FR) ;
Galland, Jean-Christophe; (Lyon, FR) ; Niccolai,
Gerald; (Villeurebanne, FR) ; Valerio, Christine;
(Villeurbanne, FR) ; Vallee, Christophe;
(Villeurbanne, FR) |
Correspondence
Address: |
Jean-Louis Seugnet
Intellectual Property Dept.
Rhodia Inc.
259 Prospect Plains Road, CN 7500
Cranbury
NJ
08512-7500
US
|
Family ID: |
8867383 |
Appl. No.: |
10/489838 |
Filed: |
August 18, 2004 |
PCT Filed: |
September 17, 2002 |
PCT NO: |
PCT/FR02/03166 |
Current U.S.
Class: |
558/348 ;
546/347 |
Current CPC
Class: |
C07C 253/10 20130101;
C07C 253/10 20130101; C07C 255/04 20130101 |
Class at
Publication: |
558/348 ;
546/347 |
International
Class: |
C07C 253/10; C07D
213/20 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 18, 2001 |
FR |
01/12040 |
Claims
1-25. (Canceled).
26. A process for the manufacture of organic compounds comprising
at least one nitrile functional group by reaction between hydrogen
cyanide and an organic compound having at least one ethylenic
unsaturation in the presence of a catalyst comprising an element
selected from the group consisting of nickel, platinum and
palladium and an organophosphorus ligand, said process comprising
the step of carrying out said reaction in a reaction medium with
the presence of an ionic liquid which comprises at least one cation
and at least one anion and which is liquid at least at a
temperature at which the reaction is carried out.
27. The process according to claim 26, wherein a solvent of low
polarity is further added to the reaction medium in order to form a
two-phase system.
28. The process according to claim 26, wherein the organophosphorus
ligand has at least one ionizable functional group or one ionic
group.
29. The process according to claim 26, wherein the ionic liquid
comprises at least one cation selected from the group consisting of
the structures tetraalkylammonium, N-alkylimidazolium,
N-alkylpyridinium, N-alkylpicolinium, N-alkyltriazolium,
N-alkylfluoropyrazolium, N-pyrrolidinium, alkylsulphonium,
tetraalkylphosphonium and alkyloxonium.
30. The process according to claim 26, wherein the ionic liquid
comprises at least one anion selected from the group consisting of
halides, nitrate, phosphate, hydrosulphate,
perfluoroalkylsulphonates, bis(perfluoroalkylsulphonyl)amides,
bis(fluorosulphonyl)amide, bis(fluorophosphoryl)amide,
tris(perfluoroalkylsulphonyl)methides, boron, aluminium, gallium
tetrahalides, iron tetrahalides, phosphorus hexahalides, arsenic
hexahalides, antimony hexahalides, zinc trihalides, tin trihalides,
and copper dihalides.
31. The process according to claim 5, wherein the anion is selected
from the group consisting of Br.sup.-, I.sup.-, BF.sub.4.sup.-,
PF.sub.6.sup.-, SbF.sub.6.sup.-, AlCl.sub.4.sup.-,
ZnCl.sub.3.sup.-, SnCl.sub.3.sup.- and
(CF.sub.3SO.sub.2).sub.2N.sup.-.
32. The process according to claim 29, wherein the cation is
selected from the group consisting of 1,3-dimethylimidazolium,
1-butyl-2,3-dimethylimid- azolium, 1-butyl-3-methylimidazolium and
1,2,3-trimethylimidazolium.
33. The process according to claim 26, wherein the ligand is an
organophosphorus ligand selected from the group consisting of
mono-dendate organophosphites, polydentate organophosphites,
organophosphonites, organophosphinites and organophosphines.
34. The process according to claim 33, wherein the organophosphorus
ligand comprises at least one ionic group.
35. The process according to claim 34, wherein the ionic group
present in the organophosphorus ligands is a sulphonate,
phosphonate, phosphinite, carboxylate or sulphinate anion.
36. The process according to claim 34, wherein the ionic group
present in the organophosphorus ligands is a guanidinium, ammonium,
pyridinium, imidazolium, phosphonium or sulphonium cation.
37. The process according to claim 26, wherein the organophosphorus
ligand is selected from the group consisting of tributylphosphine,
dimethyl(n-octyl)phosphine, tricyclohexylphosphine,
triphenylphosphine, tolylphosphine, tris(p-methoxyphenyl)phosphine,
diphenylethylphosphine, dimethylphenylphosphine,
1,4-bis(diphenylphosphino)butane, triethyl phosphite and diphenyl
phosphite.
38. The process according to claim 34, wherein the organophosphorus
ligand is selected from the group consisting of
triphenylphosphine(mono meta sodium sulphate),
(5-sodiocarboxyfur-2-yl)diphenylphosphine and
(3-sodiosulphinatophenyl)diphenylphosphine.
39. The process according to claim 27, wherein the solvent of low
polarity is selected from the group consisting of hexane, heptane,
octane, toluene, diethyl ether, diisopropyl ether and methyl
isobutyl ether.
40. The process according to claim 26, wherein the metal element of
the catalyst is nickel in the 0 or 1 oxidation state.
41. The process according to claim 26, wherein the organic compound
presenting at least one ethylenic unsaturation is an olefin or a
diolefin having from 3 to 12 carbon atoms.
42. The process according to claim 41, wherein the organic compound
presenting at least one ethylenic unsaturation is
1,3-butadiene.
43. The process according to claim 26, wherein the organic compound
having at least one ethylenic unsaturation further presents one
nitrile functional group.
44. The process according to claim 43, wherein said organic
compound is 3-pentenenitrile or 4-pentenenitrile.
45. The process according to claim 26, further comprising the step
of isomerizing branched unsaturated nitrile compounds to linear
nitrile compounds.
46. The process according to claim 45, wherein the isomerization
step is carried out in the absence of hydrogen cyanide.
47. The process according to claim 45, wherein the reaction is
carried out in the presence of a Lewis acid.
48. The process according to claim 47, wherein the Lewis acid is a
compound of the elements from Groups Ib, IIb, IIIa, IIIb, IVa, IVb,
Va, Vb, VIIb, VIIb or VIII of the Periodic Table.
49. The process according to claim 48, wherein said Lewis acid
compound is a halide, sulphate, sulphonate, carboxylate, phosphate,
halosulphonate, perhaloalkylsulphonate, fluoroalkylsulphonate,
perfluoroalkylsulphonate, bis(perfluoroalkylsulphonyl)amide, or
tris(perfluoroalkylsulphonyl)methid- e.
50. The process according to claim 47, wherein the ionic liquid
comprises an anion forming the Lewis acid.
51. The process according to claim 26, wherein the temperature of
carrying out the reaction is of between 10.degree. C. and
200.degree. C.
Description
[0001] The present invention relates to the manufacture of nitrile
compounds from unsaturated organic compounds by reaction with
hydrogen cyanide.
[0002] It relates more particularly to the manufacture of nitrile
compounds of use in the synthesis of adiponitrile, an important
chemical intermediate in the manufacture of major chemical
compounds, such as hexamethylenediamine and .epsilon.-caprolactam.
The last two compounds are used in particular in the manufacture of
polymers, such as polyamides, and more particularly polyamide-6 and
polyamide-6,6, or other polymers, such as polyurethanes.
[0003] Several processes for the manufacture of nitrile compounds
have been provided. Among these, the direct hydrocyanation of an
olefin or polyolefin, such as, for example, 1,3-butadiene, by
reaction with hydrogen cyanide is an industrially developed process
which forms the subject of numerous patents or publications.
[0004] This process consists, basically, in carrying out the
addition, in a first stage, of one molecule of HCN to one ethylenic
unsaturation, to produce an unsaturated nitrile compound. In fact,
this stage leads to the production of numerous isomers of
unsaturated nitrites. The addition of a further molecule of HCN
results, in a following stage, in a polynitrile, for example in a
dinitrile, such as adiponitrile when the starting olefin is
1,3-butadiene.
[0005] To avoid and limit the production of byproducts not having
significant use properties, the process comprises, after the first
hydrocyanation stage, a stage known as the "isomerization stage",
which consists in converting most of the branched nitrile isomers
to linear nitrile isomers, such as, in the case of the
hydrocyanation of butadiene, to 3- and 4-pentenenitriles.
[0006] These reactions are generally carried out in the liquid
phase in the presence of a catalyst based on a metal, generally
nickel, present in the form of a complex with an organic ligand.
This reaction can be carried out in a homogeneous medium, the
catalyst being soluble in the hydrocyanation medium, in particular
in the olefin or the nitrites or in a third solvent. It can also be
carried out with a medium exhibiting several liquid phases, the
catalyst being soluble in one of the phases, more specifically in
the phase formed by a polar third solvent, generally water, which
phase is distinct from that formed by the olefin and the nitrites,
at least at ambient temperature. The latter embodiment makes it
possible to more easily extract and recover the catalyst and thus
to obtain nitrile compounds comprising fewer impurities contributed
by the catalyst.
[0007] These catalytic systems have been disclosed in numerous
patents and several classes of ligands have been studied. The
ligands are generally organophosphorus compounds, such as
phosphites, phosphinites, phosphonites or phosphines. They can be
monodentate or polydentate. In the case of processes in a two-phase
medium, these organophosphorus ligands advantageously comprise one
or more ionizable groups, such as sulphonate, phosphonate,
carboxylate or ammonium groups, for example, to render them soluble
in the polar phase.
[0008] Mention may be made, as example of the disclosure of these
processes, of U.S. Pat. No. 3,496,217, which discloses the
synthesis of adiponitrile by reaction of hydrogen cyanide with
butadiene in the presence of a catalyst based on nickel complexed
with a ligand, such as triaryl phosphite. This reaction is carried
out with catalysis in a single-phase medium.
[0009] With regard to French Patent No. 2 338 253, it also
discloses a process for the synthesis of adiponitrile by
hydrocyanation of butadiene. The reaction is carried out in a
two-phase liquid medium, the catalyst being present in an aqueous
phase. This process makes it possible to recover the adiponitrile,
devoid of catalyst and therefore of metal, in the organic phase.
The catalyst disclosed is also a catalyst based on a metal, such as
nickel, in combination with a ligand of the phosphine type.
However, this ligand comprises sulphonate radicals, making it
possible to render the catalyst soluble or dispersible in
water.
[0010] Furthermore, it is also known to combine the nickel-based
catalyst with promoters, such as Lewis acids, such as, for example,
zinc chloride or triphenylborane, for the hydrocyanation of an
unsaturated nitrile compound.
[0011] Research is continually being undertaken to improve the
performance of the synthesis of nitrites by hydrocyanation, either
by developing novel catalytic systems or by modifying the reaction
conditions and compositions of the hydrocyanation medium.
[0012] Among the most recent patents published, U.S. Pat. No.
6,169,198 discloses the use of novel ligands of
metallocene-phosphorus type. Likewise, Patent U.S. Pat. No.
5,773,637 discloses the use, as Lewis acid, of
perfluoroalkylsulphonate compounds.
[0013] One of the aims of the present invention is to provide a
novel process for the manufacture of nitrites by hydrocyanation of
an olefin by reaction with hydrogen cyanide which makes it possible
to obtain high yields of and high selectivities for linear nitrites
and an improved stability of the catalytic system.
[0014] To this end, the invention provides a process for the
manufacture of organic compounds comprising at least one nitrile
functional group by carrying out a hydrocyanation reaction between
hydrogen cyanide and an organic compound comprising at least one
ethylenic unsaturation. The latter compound will be referred to,
for greater simplicity, in the present invention as an olefin or
polyolefin, when it comprises several ethylenic unsaturations.
However, this term "olefin" should not be interpreted as limiting
the organic compounds suitable for the invention to hydrocarbons
but it also relates to organic compounds comprising at least one
ethylenic unsaturation and which can comprise atoms other than
carbon and hydrogen or mixtures of hydrocarbons, such as the
mixture obtained by distillation of oil known in the hydrocarbons
field as the C.sub.4 cut. This cut is advantageously treated to
remove or convert impurities, such as compounds comprising an
acetylenic unsaturation, for example by hydrogenation, as disclosed
in U.S. Pat. No. 6,197,992. A compound will be regarded as an
"olefin" within the meaning of the present invention which
comprises an unsaturation and a nitrile functional group, such as,
for example, the unsaturated nitrile compounds obtained by the
reaction of HCN with a polyolefin.
[0015] According to one characteristic of the invention, the
reaction is carried out in the presence of a catalytic system
comprising a metal element chosen from the group consisting of
nickel, platinum and palladium and an organophosphorus ligand, the
reaction medium additionally comprising an ionic liquid which is in
the liquid state at least at the temperature at which the
hydrocyanation reaction is carried out.
[0016] In a first embodiment, the ionic liquid and the compound to
be hydrocyanated are completely miscible, at least at the reaction
temperature. The hydrocyanation reaction is carried out in a
homogeneous or single-phase medium.
[0017] In a second embodiment, the ionic liquid and the compound to
be hydrocyanated are immiscible or are only partially miscible at
the reaction temperature. The reaction is carried out in a
nonhomogeneous or two-phase medium. In this embodiment, the
catalytic system is advantageously soluble in the ionic liquid.
[0018] In both these embodiments, it is possible to add a solvent
of low polarity. This solvent of low polarity can be added from the
beginning of the reaction but can also be used only after the end
of the reaction, in order thus to promote the separation of the
hydrocyanated products and of the ionic liquid, in particular in
order to make possible the extraction of the catalytic system. This
is because the solvent of low polarity has the role of rendering
the ionic liquid insoluble in the phase composed of the said
solvent, the unconverted olefin and the nitrile compounds
formed.
[0019] Whatever the embodiment, it is preferable for the catalytic
system to be at least partially miscible in the ionic liquid.
Advantageously, this miscibility can be obtained by the presence of
at least one ionizable group in the molecule of the
organophosphorus ligand. Mention may be made, as ionizable groups,
of groups of anionic type, such as sulphonate, phosphonate,
phosphinate, carboxylate or sulphinate, or of cationic type, such
as guanidinium, ammonium, pyridinium, imidazolium, phosphonium or
sulphonium, for example. The number and the nature of these ionic
groups are preferably chosen in order to render the ligand soluble
in the ionic liquid. It can be advantageous for the nature of the
ionizable group to be identical to that of the anion or of the
cation associated with the ionic liquid.
[0020] The catalytic systems suitable for the invention are those
which preferably comprise the element nickel in the zero oxidation
state or a complex with organophosphorus ligands which can comprise
several ionizable groups described above or more generally
compounds comprising phosphorus capable of giving a coordination
compound with transition metals and more particularly the
abovementioned catalytic metals, in particular with nickel. These
compounds can be mono-, bi- or polydentate and can exhibit a
hydrophobic or hydrophilic nature. These compounds have been
disclosed in numerous patents relating to the hydrocyanation of
butadiene and belong to several classes, including in particular
the organophosphites, organophosphonites, organophosphinites and
organophosphines.
[0021] Such catalytic systems and their preparation processes are
disclosed, for example, in French Patents 2 338 253, 2 710 909, 2
711 987, 2 739 378 and 2 778 915.
[0022] Mention may be made, as examples of organic phosphorus
compounds which are suitable for the invention, of alkylphosphines,
arylphosphines, alkylarylphosphines, alkyl phosphites, aryl
phosphites, alkylaryl phosphites, alkylphosphinites,
arylphosphinites, alkylarylphosphinites, alkylphosphonites,
arylphosphonites or alkylarylphosphonites, the organic moiety of
which comprises up to 36 carbon atoms and which are preferably
substituted by one or more ionic groups described above.
[0023] Mention may be made, as examples of compounds, of
tributylphosphine, dimethyl(n-octyl)phosphine,
tricyclohexylphosphine, triphenylphosphine, tolylphosphine,
tris(p-methoxyphenyl)phosphine, diphenylethylphosphine,
dimethylphenylphosphine, 1,4-bis(diphenylphosphin- o)butane,
triethyl phosphite or diphenyl phosphite, the said compounds
preferably comprising at least one ionic group described above.
[0024] Mention may be made, as examples of such compounds, of
triphenylphosphine(mono meta sodium sulphate) (TPPMSNa),
(5-sodiocarboxyfur-2-yl)diphenylphosphine or
(3-sodiosulphinatophenyl)dip- henylphosphine.
[0025] As is disclosed in the above-mentioned patents, the catalyst
can be prepared before its introduction into the medium or in
situ.
[0026] For this, use is preferably made of the compounds of the
metals forming the catalytic element, such as nickel, which are
added to a medium in which the organophosphorus ligand is also
soluble. Such a medium can be the ionic liquid. The catalytic
system thus formed is added to the hydrocyanation medium.
[0027] The preferred compounds among the abovementioned compounds
are those of nickel. Mention may be made, as nonlimiting examples,
of:
[0028] the compounds in which the nickel is in the zero oxidation
state, such as potassium tetracyanonickelate K.sub.4[Ni(CN).sub.4],
bis(acrylonitrile)nickel(0), bis(1,5-cyclooctadiene)nickel and
derivatives comprising ligands from Group Va, such as
tetrakis(triphenylphosphine)nickel(0);
[0029] the nickel compounds in which the nickel is in an oxidation
state greater than zero, such as the carboxylates (in particular
the acetate), carbonate, bicarbonate, borate, bromide, chloride,
citrate, thiocyanate, cyanide, formate, hydroxide, hydrophosphite,
phosphite, phosphate and derivatives, iodide, nitrate, sulphate,
sulphite, aryl- and alkylsulphonates, allyl or acetylacetonate.
[0030] It is not necessary for the nickel compound to be itself
soluble in the preparation medium, such as the ionic liquid. This
is because it is sufficient for the complex to be soluble, that is
to say for the dissolution of the nickel to take place during the
addition of the ligand to the ionic liquid.
[0031] When the nickel compound used corresponds to an oxidation
state of the nickel greater than 0, a reducing agent for nickel
which preferably reacts with the latter under the reaction
conditions is added to the reaction medium. This reducing agent can
be organic or inorganic or hydrogen. Mention may be made, as
nonlimiting examples, of Zn powder, magnesium, KBH.sub.4,
NaBH.sub.4 and borohydrides preferably soluble in water.
[0032] This reducing agent is added in an amount such that the
number of oxidation/reduction equivalents is between 1 and 10.
However, values of less than 1 and greater than 10 are not
excluded.
[0033] When the nickel compound used corresponds to the 0 oxidation
state of nickel, a reducing agent of the type of those mentioned
above can also be added but this addition is not essential.
[0034] The same reducing agents are suitable when an iron compound
is used.
[0035] In the case of palladium, the reducing agents can, in
addition, be components of the reaction medium (phosphine, solvent,
olefin).
[0036] According to the invention, the reaction medium comprises an
ionic liquid. This ionic liquid is an ionic compound, the cation of
which is of onium type having at least one heteroatom, such as N, P
or S, carrying the positive charge in conjunction with a 5- or
6-membered aromatic ring, and an anion.
[0037] Such compounds are described, for example, in the article by
Yves Chauvin and Helene Olivier-Bourbigou, entitled "Nonaqueous
ionic liquids as reaction solvents", published in Chemtech, 12,
1995, p. 66, the paper by T. Welton published in Chem. Rev., 1999,
p. 2071, or patents, such as Patent EP 971 854.
[0038] According to a preferred characteristic of the invention,
the ionic liquid comprises at least one cation chosen from the
group consisting of the structures tetraalkylammonium,
N-alkylimidazolium, N-alkylpyridinium, N-alkylpicolinium,
N-alkyltriazolium, N-alkylfluoropyrazolium, N-pyrrolidinium,
alkylsulphonium, tetraalkylphosphonium and alkyloxonium.
[0039] Mention may be made, as examples of preferred cations of the
invention, of alkylimidazoliums, such as 1,3-dimethylimidazolium,
1-butyl-2,3-dimethylimidazolium, 1-butyl-3-methylimidazolium or
1,2,3-trimethylimidazolium.
[0040] Mention may be made, as preferred anions of the invention,
of an anion chosen from halides, nitrate, phosphate, hydrosulphate,
perfluoroalkylsulphonates, bis(perfluoroalkylsulphonyl)amides,
bis(fluorosulphonyl)amide, bis(fluorophosphoryl)amide,
tris(perfluoroalkylsulphonyl)methides, boron, aluminium, gallium or
iron tetrahalides, phosphorus, arsenic and antimony hexahalides,
zinc and tin trihalides, or copper dihalides.
[0041] The preferred anions of the invention are Br.sup.-, I.sup.-,
BF.sub.4.sup.-, PF.sub.6.sup.-, SbF.sub.6.sup.-, AlCl.sub.4.sup.-,
ZnCl.sub.3.sup.-, SnCl.sub.3.sup.- and
(CF.sub.3SO.sub.2).sub.2N.sup.-.
[0042] The ionic liquid, to be suitable for the process of the
invention, must be in the liquid state at least at the temperature
at which the hydrocyanation reaction is carried out. However, ionic
liquids which are found in the liquid state at a temperature of
less than 100.degree. C. are preferred as they make possible better
separation and extraction of the catalyst from the reaction medium
in the case of a two-phase system.
[0043] In addition, depending on the embodiment of the invention
(single- or two-phase system), the ionic liquid which becomes
miscible or at least partially miscible in the reaction medium only
at the temperature at which the hydrocyanation reaction is carried
out, or in the vicinity of the latter, is entirely compatible for
the implementation of the invention.
[0044] In the embodiment in a two-phase medium, the immiscibility
of the ionic liquid, at least at low temperature, is preferably
obtained by addition to the reaction medium of a solvent of low
polarity. This solvent dissolves the olefins to be hydrocyanated
and the nitrites produced and renders the ionic liquid insoluble in
the olefins and nitrites produced. Mention may be made, as solvent
of low polarity, of saturated hydrocarbons, such as hexane,
heptane, octane or toluene, or ethers, such as diethyl ether,
diisopropyl ether or methyl isobutyl ether.
[0045] The conditions for carrying out the hydrocyanation reaction
are described below, by way of example.
[0046] Thus, the amount of nickel compound or compound of another
transition metal used is chosen in order to obtain a concentration
as moles of transition metal per mole of organic compounds to be
hydrocyanated or isomerized of between 10.sup.-4 and 1 and
preferably between 0.005 and 0.5 mol of nickel or of the other
transition metal employed.
[0047] The amount of ligand used to form the catalyst is chosen so
that the number of moles of this compound with respect to 1 mol of
transition metal is between 0.5 and 50 and preferably between 2 and
10.
[0048] The hydrocyanation reaction is generally carried out at a
temperature of between 10.degree. C. and 200.degree. C. and
preferably between 30.degree. C. and 120.degree. C.
[0049] The process of the invention can be carried out continuously
or batchwise.
[0050] The hydrogen cyanide employed can be prepared from metal
cyanides, in particular sodium cyanide, or cyanohydrins, such as
acetone cyanohydrin, or by any other known synthetic process.
[0051] The hydrogen cyanide is introduced into the reactor in the
gaseous form or in the liquid form. It can also be dissolved
beforehand in an organic solvent.
[0052] In the context of a batchwise implementation, it is in
practice possible to charge to a reactor, purged beforehand using
an inert gas (such as nitrogen or argon), either a solution
comprising all or a portion of the various constituents, the
transition metal compound, the possible reducing agents and
solvents, or the said constituents separately. Generally, the
reactor is then brought to the chosen temperature and then the
compound to be hydrocyanated is introduced. The hydrogen cyanide is
then itself introduced, preferably continuously and
unvaryingly.
[0053] When the reaction is complete, the reaction mixture is
withdrawn after cooling and the reaction products are isolated, for
example by separation of the phase comprising the catalytic system
and of the phase formed by the solvent of low or no polarity, the
hydrocyanated products and those which have not been converted, in
the case of a two-phase system. The products from the latter phase
can be separated, for example by distillation. In the case of a
single-phase system, other separation means can be employed, such
as, for example, distillation or liquid/liquid extraction.
[0054] In the case where the product to be hydrocyanated is an
unsaturated compound comprising a nitrile functional group, it is
advantageous to use, with the catalytic system, a cocatalyst
comprising at least one Lewis acid.
[0055] This reaction consists in particular in converting aliphatic
nitrites comprising ethylenic unsaturation, in particular linear
pentenenitriles, such as 3-pentenenitrile, 4-pentenenitrile and
their mixtures, obtained by hydrocyanation of butadiene, to
dinitriles, more specifically to adiponitrile.
[0056] These pentenenitriles can comprise amounts, generally minor
amounts, of other compounds, such as 2-methyl-3-butenenitrile,
2-methyl-2-butenenitrile, 2-pentenenitrile, valeronitrile,
adiponitrile, 2-methylglutaronitrile, 2-ethylsuccinonitrile or
butadiene, originating from the prior reaction for the
hydrocyanation of butadiene and/or from the isomerization of
2-methyl-3-butenenitrile to pentenenitriles.
[0057] The Lewis acid used as cocatalyst makes it possible in
particular, in the case of the hydrocyanation of aliphatic nitrites
comprising ethylenic unsaturation, to improve the linearity of the
dinitriles obtained, that is to say the percentage of linear
dinitriles with respect to all the dinitriles formed, and/or to
increase the activity and the lifetime of the catalyst.
[0058] The term "Lewis acid" is understood to mean, in the present
text, according to the usual definition, compounds which accept
electron pairs.
[0059] It is possible in particular to employ the Lewis acids cited
in the work edited by G. A. Olah, "Friedel-Crafts and Related
Reactions", Volume I, pages 191 to 197 (1963).
[0060] The Lewis acids which can be employed as cocatalysts in the
present process are chosen from the compounds of the elements from
Groups Ib, IIb, IIIa, IIIb, IVa, IVb, Va, Vb, VIIb, VIIb and VIII
of the Periodic Table. These compounds are generally salts, in
particular halides, such as chlorides or bromides, sulphates,
sulphonates, halosulphonates, perhaloalkylsulphonates, in
particular fluoroalkylsulphonates or perfluoroalkylsulphonates,
carboxylates, phosphates, bis(perfluoroalkylsulphonyl)amides and
tris(perfluoroalkylsulphonyl)methi- des.
[0061] Mention may be made, as nonlimiting examples of such Lewis
acids, of zinc chloride, zinc bromide, zinc iodide, manganese
chloride, manganese bromide, cadmium chloride, cadmium bromide,
stannous chloride, stannous bromide, stannous sulphate, stannous
tartrate, indium trifluoromethylsulphonate, the chlorides or
bromides of rare-earth metal elements, such as lanthanum, cerium,
praseodymium, neodymium, samarium, europium, gadolinium, terbium,
dysprosium, hafnium, erbium, thallium, ytterbium and lutetium,
cobalt chloride, ferrous chloride or yttrium chloride.
[0062] Use may also be made, as Lewis acid, of organometallic
compounds, such as triphenylborane or titanium diisopropoxide. It
is, of course, possible to employ mixtures of several Lewis
acids.
[0063] Preference is very particularly given, among Lewis acids, to
zinc chloride, zinc bromide, stannous chloride, stannous bromide,
triphenylborane and zinc chloride/stannous chloride mixtures.
[0064] The choice will preferably be made of a Lewis acid having an
anion identical to or of the same nature as the anion of the ionic
liquid, such as, for example, zinc chloride when the ionic liquid
comprises ZnCl.sub.3.sup.- as anion, aluminium chloride when the
anion of the ionic liquid is the anion AlCl.sub.4.sup.-, lanthanum
tris(bistrifluoromethylsu- lphonylamide) when the ionic medium is
composed of the bistrifluoromethylsulphonylamide anion, or
neodymium tris(trifluoromethylsulphonate) when the anion of the
ionic medium is the trifluoromethysulphonate anion. It is also
possible to employ an ionic liquid composed of a mixture of
polynuclear anions, such as the anion Zn.sub.2Cl.sub.5.sup.- and of
ZnCl.sub.3.sup.-, or Al.sub.2Cl.sub.7.sup.-0 and of
AlCl.sub.4.sup.-.
[0065] In a preferred embodiment of the invention, the Lewis acid
will be contributed by the anion of the ionic liquid. This ionic
liquid itself contributes the effect of cocatalyst to the
medium.
[0066] The Lewis acid cocatalyst employed generally represents from
0.01 to 50 mol per mole of transition metal compound, more
particularly of nickel compound, and preferably from 1 to 10 mol
per mole.
[0067] It is also possible, under the conditions of the
hydrocyanation process of the present invention and more
particularly in the presence of an ionic liquid, to carry out, in
the absence of hydrogen cyanide, isomerization of
2-methyl-3-butenenitrile to pentenenitriles and more generally of
branched unsaturated nitrites to linear unsaturated nitrites.
[0068] The 2-methyl-3-butenenitrile subjected to isomerization
according to the invention can be employed alone or as a mixture
with other compounds.
[0069] Thus, 2-methyl-3-butenenitrile can be used as a mixture with
2-methyl-2-butenenitrile, 4-pentenenitrile, 3-pentenenitrile,
2-pentenenitrile, butadiene, adiponitrile, 2-methylglutaronitrile,
2-ethylsuccinonitrile or valeronitrile.
[0070] It is particularly advantageous to treat the reaction
mixture originating from the hydrocyanation of butadiene by HCN
according to the conditions of the invention, that is to say in the
presence of an ionic liquid.
[0071] In the context of this preferred alternative form, the
catalytic system being already present for the reaction for the
hydrocyanation of butadiene, it is sufficient to halt any
introduction of hydrogen cyanide to allow the isomerization
reaction to take place.
[0072] In this alternative form, it is possible, if appropriate, to
carry out a slight flushing of the reactor using an inert gas, such
as nitrogen or argon, for example, in order to drive off the
hydrocyanic acid which might still be present.
[0073] The isomerization reaction is generally carried out at a
temperature of 10.degree. C. to 200.degree. C. and preferably of
60.degree. C. to 120.degree. C.
[0074] In the preferred case of an isomerization immediately
following the reaction for the hydrocyanation of butadiene, it will
be advantageous to carry out the isomerization at the temperature
at which the hydrocyanation was carried out.
[0075] As for the process for the hydrocyanation of compounds
comprising ethylenic unsaturation, the catalytic system used for
the isomerization can be prepared before its introduction into the
reaction region. It is also possible to prepare the catalytic
system "in situ" by simple mixing of these various constituents.
The amount of transition metal compound and more particularly of
nickel compound used and the amount of ligand are the same as for
the hydrocyanation reaction.
[0076] However, the preparation of dinitrile compounds by
hydrocyanation of an olefin such as butadiene can be carried out
using a reaction system in accordance with the invention for the
stages of formation of the unsaturated nitrites and the stage of
isomerization above, it being possible for the reaction for the
hydrocyanation of the unsaturated nitrites to dinitriles to be
carried out with a reaction system in accordance with the invention
or any other catalytic system already known for this reaction.
[0077] Likewise, the reaction for the hydrocyanation of the olefin
to unsaturated nitrites and the isomerization of the latter can be
carried out with a reaction system different from that of the
invention, the stage of hydrocyanation of the unsaturated nitrites
to dinitriles being carried out with a reaction system in
accordance with the invention.
[0078] The examples given below, solely by way of indication, will
illustrate the invention and its advantages.
[0079] Preparation of Ionic Liquids
[0080] Synthesis of 1-butyl-2,3-dimethylimidazolium
bis(trifluoromethylsulphonyl)amide (BMMI.sup.+TF.sub.2N.sup.-)
[0081] 40.50 g (0.215 mol) of 1-butyl-2,3-dimethylimidazolium
chloride are dissolved in 300 ml of distilled water. 61.62 g (0.215
mol) of lithium bis(trifluoromethylsulphonyl)amide are added and
the mixture is stirred under argon for 72 hours at ambient
temperature. A two-phase system is formed. After extraction with
250 ml of dichloromethane, the organic phase is washed with 800 ml
of water and then concentrated. The compound exists in the form of
a slightly pinkish liquid which is purified by chromatography on a
neutral alumina column (eluent: dichloromethane). It is then
concentrated, taken up in acetonitrile in the presence of active
carbon and filtered. After drying for several hours at 60.degree.
C., the compound is obtained in the form of a colourless liquid
(83.78 g, 90%). The structure of this product:
C.sub.11H.sub.17N.sub.3S.sub.2O.sub.4F.sub- .6, is confirmed by NMR
spectral analysis.
[0082] Synthesis of 1-butyl-3-methylimidazolium
bis(trifluoromethylsulphon- yl)amide (BMI.sup.+TF.sub.2N.sup.-)
[0083] 41.92 g (0.240 mol) of 1-butyl-3-methylimidazolium chloride
are dissolved in 300 ml of distilled water. 69.46 g (0.242 mol) of
lithium bis(trifluoromethylsulphonyl)amide are added and the
mixture is stirred under argon for 90 hours at ambient temperature.
A two-phase system is formed. After extraction with 250 ml of
dichloromethane, the organic phase is washed with 800 ml of water
and then concentrated. The compound exists in the form of a
slightly pinkish liquid which is purified by chromatography on a
neutral alumina column (eluent: dichloromethane). It is then
concentrated, taken up in acetonitrile in the presence of active
carbon and filtered. After drying for several hours at 60.degree.
C., the compound is obtained in the form of a colourless liquid
(81.47 g). Its structure,
C.sub.10H.sub.15N.sub.3S.sub.2O.sub.4F.sub.6, was confirmed by NMR
analysis.
[0084] Synthesis of 1-butyl-2,3-dimethylimidazolium
hexafluorophosphate (BMMI.sup.+PF.sub.6.sup.-)
[0085] 33.37 g (0.200 mol) of sodium hexafluorophosphate and 37.50
g (0.199 mol) of 1-butyl-2,3-dimethylimidazolium chloride are
dissolved in 150 ml of acetone. After vigorous stirring at ambient
temperature under argon for 72 hours, the solution is filtered
through celite and then concentrated. After chromatography on an
alumina column (eluent: dichloromethane), the salt is taken up in
acetonitrile in the presence of active carbon and filtered.
Concentrating the solution gives 50.41 g (0.170 mol, 85%) of a
white solid. The structure of this product,
C.sub.9H.sub.17N.sub.2.PF.sub.6, is confirmed by NMR spectral
analysis.
[0086] In the examples below, the abbreviations used have the
following meanings:
[0087] cod: 1,5-cyclooctadiene
[0088] eq: equivalent
[0089] 2M3BN: 2-methyl-3-butenenitrile
[0090] 2M2BN: 2-methyl-2-butenenitrile
[0091] 3PN: 3-pentenenitrile
[0092] 4PN: 4-pentenenitrile
[0093] 3+4PN: 3PN+4PN
[0094] DN: ADN+MGN+ESN
[0095] MGN: methylglutaronitrile
[0096] ESN: ethylsuccinonitrile
[0097] DC (Y): degree of conversion of the product Y to be
hydrocyanated, corresponding to the ratio of the number of moles of
Y converted to the number of starting moles of Y
[0098] TY (X): true yield of the compound X, corresponding to the
ratio of the number of moles of X formed to the maximum number of
moles of X
[0099] YD (X): selectivity for the compound X, corresponding to the
ratio of TY (X) to DC (Y)
[0100] L: linearity: YDAdN/YDDN
[0101] GC: gas chromatography
[0102] TPPMSNa: sodium triphenylphosphate
[0103] P(Ph).sub.2PhSO.sub.2Na:
(3-sodiosulphinatophenyl)diphenylphosphine
[0104] P(Ph).sub.2FuCO.sub.2Na:
(5-sodiocarboxyfur-2-yl)diphenylphosphine
[0105] BPh.sub.3: triphenylborane
[0106] In(CF.sub.3SO.sub.3) 3 ZnPh.sub.2
[0107] Zn(CF.sub.3SO.sub.3).sub.2
[0108] Isomerization of 2-METHYL-3-BUTENENITRILE (2M3BN) to Linear
Pentenenitriles
[0109] The tests were carried out according to the following
procedure and in a "Radleys" parallel reactor which makes possible
simultaneous stirring and simultaneous reflux of 12 glass tubes
known as Schlenk tubes.
[0110] The following are introduced successively and under argon
into a glass tube:
[0111] 10 mg (0.036 mmol, 1 equivalent) of Ni(COD).sub.2-66 mg
(0.18 mmol, 5 equivalents) of TPPMSNa
[0112] 1.5 g of ionic liquid
[0113] 400 mg (4.93 mmol, 137 equivalents) of 2M3BN.
[0114] The solution is stirred at ambient temperature for 10
minutes and then 1.2 ml of heptane are added in order to obtain a
two-phase reaction medium.
[0115] The tube is closed, then stirred and heated at 100.degree.
C. for 3 hours with head cooling. At the end of the reaction, the
tubes are cooled in liquid nitrogen. A known amount of butylbenzene
(approximately 40 mg, to act as chromatography internal standard)
is added to the two-phase reaction medium, which is diluted and
homogenized by the addition of 10 ml of THF. The solution obtained
is filtered through a short silica column and injected in gas
chromatography (GC).
[0116] In the tests carried out according to the above procedure,
the starting materials comprise 2M3BN and other products. The molar
formulation of these products is given in Table I below (the main
components are shown).
1 TABLE I Component Abbreviation Mol % 2-Methyl-3-butenenitrile
2M3BN 79 2-Methyl-2-butenenitrile 2M2BN 12.70 2-Pentenenitrile 2PN
6.30 4-Pentenenitrile 4PN 0 3-Pentenenitrile 3PN 1.30
[0117] The results obtained with various salts are collated in
Table II below. By way of comparison, a test was carried out with a
catalyst based on nickel and on a ligand, triphenylphosphine, in a
single-phase medium.
2TABLE II Mass DC (%) YD (%) YD (%) YD (%) balance Ex. Salt 2M3BN
3PN + 4PN 2M2BN 2PN (%) A (1) 42 57 -3.1 5.8 86 1 [BMI] [TF.sub.2N]
95 90 2.9 -0.4 96 2 [BMMI] [PF.sub.6] 93 90 0.2 2.3 94 3 [BMMI] 96
94 0.8 1.6 98 [TF.sub.2N] (1) comparative test without ionic liquid
with triphenylphosphine as ligand
[0118] Tests were carried out without using a nonpolar solvent,
such as heptane, in order to obtain a single-phase system. The
procedure used is identical to that described above, with the
exception of the absence of nonpolar solvent. The results obtained
are listed in Table III below:
3TABLE III DC YD YD Mass Ex. Ionic liquid Duration 2M3BN 3PN + 4PN
2M2BN YD 2PN balance 4 [BMMI] [TF.sub.2N] 3 h 95 88 -0.1 0.2 92 5
[BMMI] [PF.sub.6] 3 h 94 90 1.3 1.1 95 6 [BMI] [TF.sub.2N] 3 h 94
90 1.1 0.8 97
[0119] Hydrocyanation of 3PN to ADN
[0120] The following are introduced successively and under argon
into a glass tube:
[0121] 40 mg (0.145 mmol, 1 equivalent) of Ni(COD).sub.2
[0122] 264 mg (0.72 mmol, 5 equivalents) of TPPMSNa
[0123] 1.5 ml of ionic liquid or 2.1 g, if the salt is solid at
ambient temperature
[0124] 400 mg (4.93 mmol, 34 equivalents) of 3PN
[0125] 1 equivalent of Lewis acid.
[0126] The tube is closed with a stopper fitted with a septum. The
reaction mixture is stirred and heated at 70.degree. C. for 3
hours, during which period acetone cyanohydrin is slowly added
(flow rate 0.12 ml/h, 0.36 ml, 3.95 mmol, 27 equivalents).
[0127] At the end of the reaction, 15 ml of acetone are added to
the tube, which has been cooled to ambient temperature. The
solution is stirred for 10 minutes and then poured into a flask
containing a known amount of butylbenzene (approximately 250 mg, to
act as chromatography internal standard). This solution is filtered
and injected in GC.
[0128] A first series of examples was carried out using various
Lewis acids. The results obtained are shown in Table IV below:
4 TABLE IV Ex. 7 8 9 10 11 12 Ligand TPPMSNa Ionic liquid BMMI
TF.sub.2N Lewis acid ZnCl.sub.2 BPh.sub.3
In(CF.sub.3SO.sub.3).sub.3 CoCl.sub.2 ZnPh.sub.2
Zn(CF.sub.3SO.sub.3).sub.2 DC (in %) 25.9 11.0 5.1 8.9 3.6 26.8 L
(in %) 57.3 45.5 78.5 57.9 50.6 50.9 TY (DN) (in %) 16.0 6.1 0.9
3.9 1.8 13.1 TY (NV) (in %) 2.1 3.6 0.9 1.2 1.5 1.7 Mass balance
(in %) 92.1 98.6 96.7 96.2 99.7 87.9
[0129] A second series of examples was carried out using various
ionic liquids and ligands. The results obtained are shown in Table
V below:
5 TABLE V Ex. 13 14 15 16 17 Ligands TPPMSNa
P(Ph).sub.2PhSO.sub.2Na P(Ph).sub.2FuCO.sub.2Na TPPMSNa
P(Ph).sub.2FuCO.sub.2Na Ionic liquid BMMI TF.sub.2N BMI TF.sub.2N
BMMI PF.sub.6 Lewis acid ZnCl.sub.2 DC 3PN (in %) 25.9 5.7 12.1
32.5 4.5 L (in %) 57.3 36.6 19.8 60.0 16.9 TY (DN) (in %) 16.0 2.0
7.5 23.3 2.5 TY (NV) (in %) 2.1 1.1 1.3 2.8 1.1 Mass balance (in %)
92.1 97.4 96.7 93.5 99.1
* * * * *