U.S. patent application number 09/935655 was filed with the patent office on 2002-02-07 for process for preparing phosphine oxides and process for purifying the same.
Invention is credited to Funaki, Katsuhiko, Hara, Isao, Hayashi, Takaomi, Kiyono, Shinji, Mizutani, Kazumi, Nobori, Tadahito, Shibahara, Atsushi, Takaki, Usaji.
Application Number | 20020016504 09/935655 |
Document ID | / |
Family ID | 14407417 |
Filed Date | 2002-02-07 |
United States Patent
Application |
20020016504 |
Kind Code |
A1 |
Nobori, Tadahito ; et
al. |
February 7, 2002 |
Process for preparing phosphine oxides and process for purifying
the same
Abstract
To provide a process for preparing phosphine oxides comprising
reacting iminophosphoranes with phosphorus oxytrichloride by which
highly purified phosphine oxides can be obtained industrially in a
higher yield. Specifically, phosphine oxides are prepared in such a
manner that iminophosphoranes are reacted with phosphorus
oxytrichloride using an aprotic organic solvent with permittivity
2.2 or more at 20.degree. C. as a solvent under special reaction
conditions to give a liquid reaction product containing phosphine
oxides and aminophosphonium chlorides which are yielded as a
by-product at the same time as the phosphine oxides, and the above
described chlorides are removed from the above described liquid
reaction product by the solid-liquid separation process, and the
solution having been subjected to the solid-liquid separation
process is washed with water.
Inventors: |
Nobori, Tadahito; (Kanagawa,
JP) ; Hara, Isao; (Kanagawa, JP) ; Funaki,
Katsuhiko; (Chiba, JP) ; Hayashi, Takaomi;
(Chiba, JP) ; Shibahara, Atsushi; (Chiba, JP)
; Kiyono, Shinji; (Chiba, JP) ; Mizutani,
Kazumi; (Kanagawa, JP) ; Takaki, Usaji;
(Kanagawa, JP) |
Correspondence
Address: |
Robert G. Mukai
BURNS, DOANE, SWECKER & MATHIS, L.L.P.
P.O. Box 1404
Alexandria
VA
22313-1404
US
|
Family ID: |
14407417 |
Appl. No.: |
09/935655 |
Filed: |
August 24, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
09935655 |
Aug 24, 2001 |
|
|
|
09548624 |
Apr 13, 2000 |
|
|
|
6303815 |
|
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Current U.S.
Class: |
564/12 ; 546/21;
548/412 |
Current CPC
Class: |
C07F 9/224 20130101;
C07F 9/025 20130101 |
Class at
Publication: |
564/12 ; 548/412;
546/21 |
International
Class: |
C07F 009/547; C07F
009/02 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 13, 1999 |
JP |
105431/1999 |
Claims
1. A process for preparing phosphine oxides having the following
formula (2): 3wherein R represents the same kind of or different
kinds of hydrocarbon group(s) with 1 to 10 carbon atoms, and two Rs
on the same nitrogen atom can combine with each other to form a
ring structure, which comprises reacting iminophosphoranes having
the following formula (1): 4wherein R is the same as that of the
formula (2), with phosphorus oxytrichloride, in the presence of an
aprotic organic solvent with permittivity 2.2 or more at 20.degree.
C. as a reaction solvent.
2. The process for preparing phosphine oxides according to claim 1,
wherein R of said iminophosphoranes having the formula (1) and of
said phosphine oxides having the formula (2) is a methyl group.
3. The process for preparing phosphine oxides according to claim 1
or 2, wherein said aprotic organic solvent does not dissolve
aminophosphonium chlorides having the following formula (3):
5wherein R is the same as that of the formulae (1) and (2).
4. The process for preparing phosphine oxides according to claim 1
or 2, wherein said aprotic organic solvent does not dissolve
aminophosphonium chlorides having the formula (3) and is
substantially immiscible with water.
5. The process for preparing phosphine oxides according to any one
of claims 1 to 4, wherein the number of moles of said
iminophosphoranes having the formula (1) used per 1 mole of
phosphorus oxytrichloride is in the range of 6 to 10.
6. A process for purifying phosphine oxides having the formula (2)
which comprises water washing of a solution containing at least
said phosphine oxides and an organic solvent substantially
immiscible with water to give a solution of said phosphine oxides,
or further comprising concentration to dry said solution having
been subjected to water washing to give solid phosphine oxides.
7. The process for purifying phosphine oxides according to claim 6,
wherein R of said phosphine oxides having the formula (2) is a
methyl group.
8. The process for purifying phosphine oxides according to claim 6
or 7, wherein said organic solvent substantially immiscible with
water is an aprotic organic solvent with permittivity 2.2 or more
at 20.degree. C. which does not dissolve aminophosphonium chlorides
having the formula (3).
9. The process for purifying phosphine oxides according to claim 6
or 7, wherein said solution containing at least phosphine oxides
having the formula (2) and an organic solvent substantially
immiscible with water is a solution obtained by removing solid
aminophosphonium chlorides having the formula (3) from a liquid
reaction product containing phosphine oxides having the formula (2)
and the above described aminophosphonium chlorides by the
solid-liquid separation process, wherein the liquid reaction
product is formed by reacting iminophosphoranes having the formula
(1) with phosphorus oxytrichloride using as a reaction solvent an
aprotic organic solvent with permittivity 2.2 or more at 20.degree.
C. which is substantially immiscible with water and does not
dissolve the aminophosphonium chlorides having the formula (3), the
above descried phosphine oxides and phosphonium chlorides being
yielded at the same time by the above described reaction.
10. The process for purifying phosphine oxides according to claim
9, wherein the number of moles of said iminophosphoranes having the
formula (1) which are used per 1 mole of phosphorus oxytrichloride
is in the range of 6 to 10.
11. The process for purifying phosphine oxides according to any one
of claims 6 to 10, wherein phosphine oxides are obtained as a
solution in such a manner that said solution of phosphine oxides
having the formula (2) obtained by water washing is concentrated to
dry, saturated aliphatic hydrocarbon is added to the dried solid
obtained, and the solid left undissolved is removed by the
solid-liquid separation process, or obtained as a solid by
concentrating to dry said solution of phosphine oxides which has
been subjected to said solid-liquid separation process.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates to a process for preparing phosphine
oxides having the general formula (2) which comprises reacting
iminophosphoranes having the general formula (1) with phosphorus
oxytrichloride and to a process of purifying the above described
phosphine oxides. The present inventors previously found that the
above described phosphine oxides are very effective as
polymerization catalysts for polymerizing alkylene oxide compounds,
as catalysts for producing oxyalkylene derivatives from epoxy
compounds, or as curing catalysts for curing the raw material resin
for IC sealing, and already filed an application for a patent on
each of the above described catalysts (Japanese Patent Application
No. 10-106745, Japanese Patent Laid-Open Nos. 11-302371 or
11-322901, etc.).
[0003] 2. Prior Art
[0004] Except for the present inventors' patent documents, the only
publicly-known literature on phosphine oxides having the general
formula (2) is the one disclosed by G. N. Koidan et al., in Journal
of General Chemistry of the USSR, 55, p1453 (1985).
[0005] In this literature, the compound referred to as
iminotris(dimethylamino)phosphorane in this patent application,
which is iminophosphorane having the general formula (1) whose R is
a methyl group, is termed hexamethyltriamidophosphazo hydride and
the compound referred to as
tris[tris(dimethylamino)-phosphoranylidenamino]phosphine oxide in
this patent application, which is phosphine oxide having the
general formula (2) whose R is a methyl group, is termed
tris[tris(N,N-dimethylamido)phosphazo]phosphate.
[0006] And the compound referred to as
aminotris(dimethylamino)phosphonium chloride in this patent
application, which is aminophosphonium chloride having the general
formula (3) whose R is a methyl group, is the same as the compound
termed hexamethyltriamidophosphazo hydride hydrochloride and shown
by the form of [HN.dbd.P(NMe.sub.2).sub.3].HCl in the above
described literature. Hereinafter, for the above described three
kinds of compounds the expressions of this application shall be
used.
[0007] In the above literature, described is the- reaction of
tris[tris(dimethylamino)phosphoranylidenamino]phosphine oxide with
methyl iodide. And a process for preparing
tris[tris(dimethylamino)phosphoranyli- denamino]phosphine oxide,
the raw material of the above reaction, is disclosed.
[0008] The literature states that
tris[tris(dimethylamino)phosphoraniliden- amino]phosphine oxide was
obtained in an isolation yield of 85% by, first, adding a solution
of phosphorus oxytrichloride in petroleum ether to a solution of
iminotris(dimethylamino) phosphorane in petroleum ether drop by
drop at 20.degree. C. for 30 minutes while stirring the solution
mixture so that the mole ratio of the above described phosphorane
to phosphorus oxytrichloride becomes exactly 6:1, after that (the
time is not specified), separating the precipitate of
aminotris(dimethylamino)pho- sphonium chloride as a by-product,
washing the above described precipitate with petroleum ether,
concentrating the filtrate, followed by crystallizing the residue
from a small amount of the petroleum ether.
[0009] However, when the present inventors carried out the
preparation of
tris[tris(dimethylamino)phosphoranilidenamino]phosphine oxide under
the same conditions as above, even after the addition of phosphorus
oxytrichloride at 20.degree. C. for 30 minutes, almost no object
compound was produced, as shown in comparative example 5 below.
After that, the reaction was proceeded at a raised temperature of
40.degree. C. for 24 hours, however, the reaction yield of the
object compound was as low as about 60%. Even after the additional
48 hours of reaction, the reaction yield was about 73% at the
most.
[0010] In addition, the above literature only states that
tris[tris(dimethylamino)phosphoranylidenamino]phosphine oxide was
obtained "by crystallizing the residue from a small amount of the
petroleum ether", but does not describe in detail the
recrystallization process. The present inventors attempted
recrystallization of crude said phosphine oxide in such a manner
that, first precipitate was separated by filtration from the liquid
reaction product obtained after the 48 hours' reaction at
40.degree. C., as described above, then the filtrate was
concentrated to dry to become a solid.
[0011] As shown in comparative example 6 below, a small amount of
crystal deposition was observed only after the filtrate was cooled
to -10.degree. C., and the crystal could be finally gathered after
the filtrate was cooled to an extremely low temperature of
-20.degree. C. The isolation yield of the crystal, that is, the
isolation yield of
tris[tris(dimethylamino)phosphoranylidenamino]phosphine oxide was
as low as 20%, and moreover, the crystal contained a large amount
of chlorine ion (about 600 ppm). Such residue of chlorine ion is a
very serious problem when the above described phosphine oxide is
used as a curing catalyst for curing the raw material resin for IC
sealing which is required to have an electrical insulating
property.
[0012] In the case where
tris[tris(dimethylamino)phosphoranylidenamino]pho- sphine oxide is
prepared by reacting iminotris(dimethylamino) phosphorane with
phosphorus oxytrichloride, if one molecule of
iminotris(dimethylamino) phosphorane reacts with one molecule of
phosphorus oxytrichloride, one molecule of hydrogen chloride is
yield at the same time. This hydrogen chloride immediately reacts
with iminotris(dimethylamino) phosphorane to yield ionic
aminotris(dimethylamino)phosphonium chloride. Accordingly, 6 moles
of iminotris(dimethylamino) phosphorane is required
stoichiometrically so as to react all of the three chlorines of one
mole of phosphorus oxytrichloride. This is expressed by the
following reaction equation.
6HN.dbd.P(NMe).sub.2).sub.3+O.dbd.PCl.sub.3.fwdarw.O.dbd.P[N.dbd.P(NMe.sub-
.2).sub.3].sub.3+3[H.sub.2N--P.sup.+(NMe.sub.2).sub.3]Cl.sup.-
[0013] As shown in comparative example 7 below, in the purifying
process described in the above described literature, when
imino(dimethylamino) phosphorane was used in excess of that
stoichiometrically required so as to increase yields, the unreacted
residue of the above described phosphorane could not be removed
sufficiently, which led to a decrease in purity of recrystallized
tris[tris(dimethylamino)phosphoranylidenamino]ph- osphine
oxide.
[0014] Thus, the above disclosed process for preparing
tris[tris(dimethylamino)phosphoranylidenamino]phosphine oxide is
still very insufficient as an industrial process in that: its
reaction and isolation yields are low, the purification process for
its product requires an extremely low temperature, the ionic
compound yielded by its reaction cannot be removed sufficiently,
and its unreacted raw material cannot be removed sufficiently when
using one reactant in excess of that stoichiometrically required in
order to increase yields.
SUMMARY OF THE INVENTION
[0015] Accordingly, it is a primary object of the present invention
to provide a process for preparing phosphine oxides having the
general formula (2) in a raised yield which comprises reacting
iminophosphoranes having the general formula (1) with phosphorus
oxytrichloride.
[0016] Another object of the present invention is to provide a
process for purifying the above described phosphine oxides which
makes it possible in an industrially more realistic manner to
remove unreacted raw materials and ionic impurities in a liquid
reaction product and to provide a high yield and purity of the
above described phosphine oxides.
[0017] After continuously concentrating their energies on
investigating processes for preparing and purifying the above
described phosphine oxides so as to achieve the above objects, the
present inventors finally found that in the process for preparing
phosphine oxides having the general formula (2) which comprises
reacting iminophosphoranes having the general formula (1) with
phosphorus oxytrichloride, the use of an aprotic organic solvent
with permittivity 2.2 or more at 20.degree. C. instead of petroleum
ether (with permittivity 1.85 to 1.95 at 20.degree. C.), as a
reaction solvent, increases the reaction rate remarkably and gives
the above described phosphine oxides in a high yield.
[0018] In addition, it was found that, although one part by weight
of petroleum ether is a good solvent to dissolve 1.5 parts by
weight or more of the above described phosphine oxides, when the
liquid reaction product reacted in a petroleum ether as a reaction
solvent is washed with a small amount of water, almost all amount
of the above described phosphine oxides moves to a water phase and
there is almost none left in a petroleum ether phase.
[0019] Surprisingly, however, it was found that in a liquid
reaction product obtained by using a specific solvent, such as
o-dichlorobenzene, almost all amount of the above described
phosphine oxides is left in an organic phase even after
water-washing and almost all amount of the aminophosphonium
chlorides having the general formula (3) which are yielded by the
reaction and the unknown compounds as by-products move to a water
phase, as shown in example 8 below. Further surprisingly, it was
also found that, when iminophosphoranes are used in a
stoichiometrically required amount or in excess of the same amount,
almost all amount of the iminophosphoranes having the general
formula (1) which are left unreacted in the liquid reaction product
move to a water phase.
[0020] As described above, the present inventors found that the use
of an aprotic organic solvent with permittivity 2.2 or more at
20.degree. C. as a reaction solvent is effective in increasing the
reaction rate as well as the reaction yield, as a result, producing
the phosphine oxides having the general formula (2) in a high
yield, and in increasing the purity of the above described
phosphine oxides simply by water-washing the solution containing
the above described phosphine oxides and a specific organic solvent
while keeping the isolation yield almost the same. Thus the present
invention was completed.
[0021] Accordingly, the first aspect of the present invention is a
process for preparing phosphine oxides having the following general
formula (2): 1
[0022] wherein R represents the same kind or different kinds of
hydrocarbon group(s) with 1 to 10 carbon atom(s), and two Rs on the
same nitrogen atom can combine with each other to form a ring
structure, which comprises reacting iminophosphoranes having the
following general formula (1): 2
[0023] wherein R is the same as that of the formula (2), with
phosphorus oxytrichloride, in the presence of an aprotic organic
solvent with permittivity 2.2 or more at 20.degree. C. as a
reaction solvent.
[0024] The second aspect of the present invention is a process for
purifying phosphine oxides which comprises water-washing a solution
containing at least phosphine oxides having the general formula (2)
and an organic solvent which does not substantially mix with water
to give the above described phosphine oxides as a solution, or
concentrating to dry the above described solution to give the above
described phosphine oxides as a solid.
DETAILED DESCRIPTION OF THE INVENTION
[0025] In the preparation and purification processes of the present
invention, the chemical structure of phosphine oxides is expressed
by the general formula (2); however, the formula just expresses one
canonical structure. According to the formula (2), a double bond is
formed between phosphorus atom and oxygen atom; however, phosphine
oxides may have another canonical structure where electrons cluster
on the side of oxygen atom to form an anion of oxygen and a cation
of phosphorus (P.sup.+--O.sup.-). The cation of phosphorus may be
delocalized through a conjugated system. It should be understood
that phosphine oxides having the formula (2) in the preparation and
purification processes of the present invention are resonance
hybrids including all of the above described structure.
[0026] In the preparation and purification processes of the present
invention, R of iminophosphoranes having the general formula (1),
of phosphine oxides having the formula (2) and of aminophosphonium
chlorides having the formula (3) represents the same kind of or
different kinds of hydrocarbon group(s) with 1 to 10 carbon
atom(s). In particular, the R represents an aliphatic or aromatic
hydrocarbon group such as methyl, ethyl, n-propyl, isopropyl,
allyl, n-butyl, sec-butyl, tert-butyl, 2-butenyl, 1-pentyl,
2-pentyl, 3-pentyl, 2-methyl-1-butyl, isopentyl, tert-pentyl,
3-methyl-2-butyl, neopentyl, n-hexyl, 4-methyl-2-pentyl,
cyclopentyl, cyclohexyl, 1-heptyl, 3-heptyl, 1-octyl, 2-octyl,
2-ethyl-1-hexyl, 1,1-dimethyl-3,3-dimethylbutyl (commonly known as
tert-octyl), nonyl, decyl, phenyl, 4-toluyl, benzyl, 1-phenylethyl,
or 2-phenylethyl.
[0027] When two Rs on the same nitrogen atom of iminophosphoranes
having the general formula (1), of phosphine oxides having the
formula (2) and of aminophosphonium chlorides having the formula
(3) combine with each other to form a ring structure together with
the nitrogen atom, the formed cyclic amino groups are cyclic
secondary amino groups containing 4 to 6 carbon atoms on the ring,
and --NR.sub.2's are cyclic secondary amino groups of 5 to 7
members including a nitrogen atom.
[0028] The above described cyclic secondary amino groups include,
for example, pyrrolidine-1-yl group, piperidine-1-yl group,
morpholine-4-yl group, and substitution products thereof
substituted with alkyl groups such as methyl group and ethyl
group.
[0029] All of or part of the potential nitrogen atoms of the above
described iminophosphoranes, phosphine oxides and aminophosphonium
may participate in the formation of such a ring structure.
[0030] R is preferably an aliphatic hydrocarbon group with 1 to 8
carbon atoms, such as methyl, ethyl, n-propyl, isopropyl,
tert-butyl, tert-pentyl, or 1,1-dimethyl-3,3-dimethylbutyl, and
more preferably a methyl group.
[0031] The above described iminophosphoranes having the general
formula (1) can be synthesized in the same manner as the
description in EP-0921128 or G. N. Koidan et al., Zh. Obshch.
Khim., 50, 679-680 (1980). Of the above described
iminophosphoranes, the one whose R is a methyl group is
commercially available.
[0032] The first aspect of the present invention is a process for
preparing phosphine oxides having the formula (2) which comprises
reacting iminophosphoranes having the general formula (1) with
phosphorus oxytrichloride, wherein an aprotic organic solvent with
permittivity 2.2 or more at 20.degree. C. is used as a reaction
solvent.
[0033] The preparation process of the present invention is
characterized by use of an aprotic organic solvent with
permittivity 2.2 or more at 20.degree. C. as a reaction solvent.
The use of an aprotic organic solvent with permittivity less than
2.2 at 20.degree. C. as a reaction solvent causes an extreme
decrease in reaction rate under the same mild conditions. On the
other hand, if the reaction temperature is raised so as to increase
the reaction rate, a side reaction proceeds, as a result of which
phosphine oxides having the general formula (2) cannot be obtained
in a high yield.
[0034] The aprotic organic solvents with permittivity less than 2.2
at 20.degree. C. include, for example, petroleum ether (1.85 to
1.95; permittivity at 20.degree. C. and so on), hexane (1.89),
decane (1.99), 1-hexene(2.06), 1-octene (2.08), cyclohexane (2.05)
and decalin (2.19), all of which are not preferable as a reaction
solvent of the present invention.
[0035] Concrete examples of the aprotic organic solvents with
permittivity 2.2 or more at 20.degree. C. used in the preparation
process of the present invention as a reaction solvent include, for
example, halogenated aliphatic hydrocarbons such as methylene
chloride, chloroform, 1,2-dichloroethane, 1,1-dichloroethane or
hexachloroethane; aromatic hydrocarbons such as benzene, toluene,
o-xylene, m-xylene, p-xylene, mixed xylene, ethylbenzene, normal
propylbenzene, cumene, 1,2,3-trimethylbenzene,
1,2,4-trimethylbenzene, mesitylene, tetralin, butylbenzene,
p-cymene, cyclohexylbenzene, 1,4-diethylbenzene,
1,3-diisopropylbenzene or dodecylbenzene; halogenated aromatic
hydrocarbons such as chlorobenzene, o-dichlorobenzene,
m-dichlorobenzene, bromobenzene, o-dibromobenzene,
1-bromo-2-chlorobenzene, 1-bromonaphthalene, 1-chloronaphthalene,
2-chlorotoluene, 2-bromotoluene, 2,4-dichlorotoluene,
1-bromo-2-ethylbenzene, 2-chloro-o-xylene or
1,2,4-trichlorobenzene; ethers such as diethyl ether, dipropyl
ether, diisopropyl ether, dibutyl ether, dimethoxyethane,
diethylene glycol dimethyl ether, tetrahydrofuran, tetrahydropyran,
1,4-dioxane, anisole or phenetol; esters such as methyl formate,
ethyl formate, propyl formate, isobutyl formate, methyl acetate,
ethyl acetate, propyl acetate, butyl acetate, methyl propionate,
ethyl propionate, methyl butyrate, methyl benzoate, isopentyl
benzoate or ethyl cinnamate; nitro compounds such as nitromethane,
nitroethane or nitrobenzene; and polar compounds such as
acetonitrile, propionitrile, benzonitrile, N,N-dimethylformamide,
N-methylpyrrolidone, dimethyl sulfoxide or
hexamethylphosphorictriamide. For further detailes, refer to Teruzo
Asahara et al. Handbook of Solvents (Tokyo: Kodansha Publishing
Company, 1982).
[0036] Any other aprotic organic solvents may be used, as long as
their permittivity is 2.2 or more at 20.degree. C. and they do not
hinder the preparation process of the present invention. These
aprotic organic solvents may be used independently or jointly.
Further, the aprotic organic solvent system which is a mixture of
the above described aprotic organic solvents and the aprotic
organic solvents with permittivity less than 2.2 at 20.degree. C.
and allowed to have permittivity of 2.2 or more at 20.degree. C.
should be understood as an "aprotic organic solvent with
permittivity 2.2 or more at 20.degree. C." in the preparing process
of the present invention.
[0037] Of these aprotic organic solvents, preferable are those do
not dissolve aminophosphonium chlorides having the formula (3)
described below. The preferable aprotic organic solvents include,
for example, aromatic hydrocarbons such as benzene, toluene,
o-xylene, m-xylene, p-xylene, mixed xylene, ethylbenzene, normal
propylbenzene, cumene, 1,2,3-trimethylbenzene,
1,2,4-trimethylbenzene, mesitylene, tetralin, butylbenzene,
p-cymene, cyclohexylbenzene, 1,4-diethylbenzene,
1,3-diisopropylbenzene or dodecylbenzene; halogenated aromatic
hydrocarbons such as chlorobenzene, o-dichlorobenzene,
m-dichlorobenzene, bromobenzene, o-dibromobenzene,
1-bromo-2-chlorobenzene, 1-bromonaphthalene, 1-chloronaphthalene,
2-chlorotoluene, 2-bromotoluene, 2,4-dichlorotoluene,
1-bromo-2-ethylbenzene, 2-chloro-o-xylene or
1,2,4-trichlorobenzene; and ethers such as diethyl ether, dipropyl
ether, diisopropyl ether, dibutyl ether, dimethoxyethane,
diethylene glycol dimethyl ether, tetrahydrofuran, tetrahydropyran,
1,4-dioxane, anisole or phenetol.
[0038] Of the above described aprotic organic solvents, more
preferable are those substantially immiscible with water as
described in the purification process of the present invention. The
aprotic organic solvents substantially immiscible with water
include, for example, aromatic hydrocarbons such as benzene,
toluene, o-xylene, m-xylene, p-xylene, mixed xylene, ethylbenzene,
normal propylbenzene, cumene, 1,2,3-trimethylbenzene,
1,2,4-trimethylbenzene, mesitylene, tetralin, butylbenzene,
p-cymene, cyclohexylbenzene, 1,4-diethylbenzene,
1,3-diisopropylbenzene or dodecylbenzene; and halogenated aromatic
hydrocarbons such as chlorobenzene, o-dichlorobenzene,
m-dichlorobenzene, bromobenzene, o-dibromobenzene,
1-bromo-2-chlorobenzene, 1-bromonaphthalene, 1-chloronaphthalene,
2-chlorotoluene, 2-bromotoluene, 2,4-dichlorotoluene,
1-bromo-2-ethylbenzene, 2-chloro-o-xylene or
1,2,4-trichlorobenzene. And more preferable are toluene,
chlorobenzene, dichlorobenzene or 2,4-dichlorotoluene.
[0039] The amount of these aprotic organic solvents used is not
expressly restricted; however, it is normally 500 weight parts or
less per 1 weight part of phosphorus oxytrichloride as a raw
material, preferably 1 to 100 weight parts, and more preferably 1.5
to 50 weight parts. It is not a problem that part of the liquid
phosphorus oxytrichloride can be immiscible with these aprotic
organic solvents.
[0040] In the preparation process of the present invention, the
mole ratio of iminophosphoranes having the formula (1) used to
phosphorus oxytrichloride is not expressly restricted; however, it
is normally 5 to 12, preferably 6 to 10, and more preferably 6.1 to
8.0.
[0041] The reaction temperature varies depending on the amount of
solvent used, on the mole ratio of the raw materials, etc.;
however, it is normally -10 to 200.degree. C., preferably 0 to
150.degree. C., and more preferably 15 to 100.degree. C. In the
reaction, the set temperature may be changed phase by phase; for
example, the reaction may be carried out at a relatively low
temperature in the beginning and at a relatively high temperature
in the last.
[0042] The reaction may be carried out under reduced pressure,
under normal pressure and under pressure; however, it is normally
carried out under normal pressure. The reaction time varies
depending on the reaction temperature and other factors; however,
it is normally 0.1 to 100 hours, preferably 0.5 to 50 hours, and
more preferably 1 to 30 hours.
[0043] In the liquid reaction product thus obtained,
aminophosphonium chlorides having the formula (3) can sometimes be
deposited as a solid and can sometimes be dissolved depending on
the kind or amount of the solvent used or on the kind of
iminophosphoranes having the formula (1). The methods of removing
the above described phosphonium chlorides in such states are not
restricted to specific ones and any methods can be used to remove
them; however, when the above described phosphonium chlorides are
deposited in the liquid reaction product as a solid, the method in
which the liquid reaction product directly undergoes a solid-liquid
separation is normally used; and when the above described
phosphonium chlorides are dissolved in the liquid reaction product,
first the solvent used is distilled from the liquid, then another
organic solvent which does not dissolve the above described
phosphonium chlorides is added, and the liquid reaction product can
undergo a solid-liquid separation.
[0044] The above solid-liquid separation can be conducted using any
methods; however, general-purpose methods such as filtration,
centrifugation and decantation are normally used. Of the above
methods, filtration is most preferable. If needed, filter cake can
be washed with the above described aprotic organic solvent or an
organic solvent which does not dissolve the above described
phosphonium chlorides, and the washings may be added to the
filtrate.
[0045] The organic solvents which do not dissolve the above
described phosphonium chlorides include, for example, saturated
aliphatic hydrocarbons such as normal pentane, normal hexane,
2,2-dimethylbutane, 2,3-dimethylbutane, 2-methylpentane, normal
heptane, normal octane, 2,3,3-trimethylpentane, isooctane, normal
nonane, 2,2,5-trimethlhexane or normal decane; alicyclic
hydrocarbons such as cyclopentane, methylcyclopentane, cyclohexane,
methylcyclohexane, ethylcyclohexane, p-menthane, bicyclohexyl or
decalin; aromatic hydrocarbons such as benzene, toluene, o-xylene,
m-xylene, p-xylene, mixed xylene, ethylbenzene, normal
propylbenzene, cumene, 1,2,3-trimethylbenzene,
1,2,4-trimethylbenzene, mesitylene, tetralin, butylbenzene,
p-cymene, cyclohexylbenzene, 1,4-diethylbenzene,
1,3-diisopropylbenzene or dodecylbenzene; halogenated aromatic
hydrocarbons such as chlorobenzene, o-dichlorobenzene,
m-dichlorobenzene, bromobenzene, o-dibromobenzene,
1-bromo-2-chlorobenzene, 1-bromonaphthalene, 1-chloronaphthalene,
2-chlorotoluene, 2-bromotoluene, 2,4-dichlorotoluene,
1-bromo-2-ethylbenzene, 2-chloro-o-xylene or
1,2,4-trichlorobenzene; and ethers such as diethyl ether, dipropyl
ether, diisopropyl ether, dibutyl ether, dimethoxyethane,
diethylene glycol dimethyl ether, tetrahydrofuran, tetrahydropyran,
1,4-dioxane, anisole or phenetol. The organic solvents which do not
dissolve the above described phosphonium chlorides are, however,
limited to the above described ones.
[0046] The above described phosphonium chlorides separated as
solids can be re-formed as iminophosphoranes having the formula (1)
by the method described in EP-0921128 or G. N. Koidan et al., Zh.
Obshch. Khim., 50, 679-680 (1980) and recycled as part or the whole
of the iminophosphoranes having the formula (1) in the preparation
process of the present invention.
[0047] In the mother liquor from which the aminophosphonium
chlorides having the formula (3) have been removed, there exist
iminophosphoranes having the formula (1) which remain unreacted or
are added in excess. The methods of removing the above described
phosphoranes are not restricted to specific ones and any methods
can be used to remove them; however, normally used are the method
in which the above described mother liquor is concentrated to dry
and the above described phosphoranes are distilled off under normal
pressure or under reduced pressure and the method in which the
above described mother liquor is washed with water as described
below.
[0048] The dried solid and the solution having undergone water
washing thus obtained contain phosphine oxides having the formula
(2) of a sufficiently high purity. Although they can sometimes be
used as they are for next purpose, they can sometimes be used as a
concentrated solution or a solid by removing a small amount of
water contained therein with a drying agent or by distillation or,
in case of solutions having undergone the above described water
washing, by removing part of or the whole solvent used.
[0049] The second aspect of the present invention is a process for
purifying phosphine oxides having the formula (2) which comprises
water washing a solution containing at least the above described
phosphine oxides and an organic solvent substantially immiscible
with water to give the above described phosphine oxides as a
solution, or further comprises concentrating to dry the above
described solution to give the above described phosphine oxides as
a solid.
[0050] "The organic solvents substantially immiscible with water"
used in the purification process of the present invention mean
organic solvents conventionally used for extraction etc. which
dissolve in water too little to be taken into consideration and can
be easily separated from water phase. In addition, the partition
rate of their phase to water phase is high in terms of phosphine
oxides having the formula (2), and they cause no chemical process
even if they come in contact with the above described phosphine
oxides. The organic solvents substantially immiscible with water as
described above include, for example, halogenated aliphatic
hydrocarbons such as methylene chloride, chloroform,
1,2-dichloroethane, 1,1-dichloroethane or hexachloroethane;
aromatic hydrocarbons such as benzene, toluene, o-xylene, m-xylene,
p-xylene, mixed xylene, ethylbenzene, normal propylbenzene, cumene,
1,2,3-trimethylbenzene, 1,2,4-trimethylbenzene, mesitylene,
tetralin, butylbenzene, p-cymene, cyclohexylbenzene,
1,4-diethylbenzene, 1,3-diisopropylbenzene or dodecylbenzene;
halogenated aromatic hydrocarbons such as chlorobenzene,
o-dichlorobenzene, m-dichlorobenzene, bromobenzene,
o-dibromobenzene, 1-bromo-2-chlorobenzene, 1-bromonaphthalene,
1-chloronaphthalene, 2-chlorotoluene, 2-bromotoluene,
2,4-dichlorotoluene, 1-bromo-2-ethylbenzene, 2-chloro-o-xylene or
1,2,4-trichlorobenzene; and esters having 4 or more of carbon atoms
such as propyl formate, isobutyl formate, ethyl acetate, propyl
acetate, butyl acetate, methyl propionate, ethyl propionate, methyl
butylate, methyl benzoate, isopentyl benzoate or ethyl cinnamate.
Any other organic solvents may be used, as long as they do not
hinder the purification process of the present invention.
[0051] Of the above described organic solvents, preferable are
aprotic organic solvents with permittivity 2.2 or more at
20.degree. C. which do not dissolve aminophosphonium chlorides
having the formula (3). The preferable aprotic organic solvents
include, for example, aromatic hydrocarbons such as benzene,
toluene, o-xylene, m-xylene, p-xylene, mixed xylene, ethylbenzene,
normal propylbenzene, cumene, 1,2,3-trimethylbenzene,
1,2,4-trimethylbenzene, mesitylene, tetralin, butylbenzene,
p-cymene, cyclohexylbenzene, 1,4-diethylbenzene,
1,3-diisopropylbenzene or dodecylbenzene; and halogenated aromatic
hydrocarbons such as chlorobenzene, o-dichlorobenzene,
m-dichlorobenzene, bromobenzene, o-dibromobenzene,
1-bromo-2-chlorobenzene, 1-bromonaphthalene, 1-chloronaphthalene,
2-chlorotoluene, 2-bromotoluene, 2,4-dichlorotoluene,
1-bromo-2-ethylbenzene, 2-chloro-o-xylene or
1,2,4-trichlorobenzene. More preferable are toluene, chlorobenzene
or o-dichlorobenzene.
[0052] "A solution containing at least phosphine oxides having the
formula (2) and an organic solvent substantially immiscible with
water" used in the purification process of the present invention
means a solution containing at least the above described two
components, and there may exist other components in the solution,
as long as they do not hinder the purification process of the
present invention. Further, the solution may be a solution formed
by dissolving the above described phosphine oxides, which was once
separated from another solution, in an organic solvent
substantially immiscible with water.
[0053] Further, the solution may be a solution formed by removing
solid aminophosphonium chlorides having the formula (3) from a
liquid reaction product containing phosphine oxides having the
formula (2) and the above described aminophosphonium chlorides by
the solid-liquid separation process, wherein the liquid reaction
product is formed by reacting iminophosphoranes having the formula
(1) with phosphorus oxytrichloride using as a reaction solvent an
aprotic organic solvent with permittivity 2.2 or more at 20.degree.
C. which is substantially immiscible with water and does not
dissolve the aminophosphonium chlorides having the formula (3), the
above descried phosphine oxides and phosphonium chlorides being
yielded at the same time by the above described reaction. According
to the situations, the solution may be a solution formed in such a
manner that, first the above described reaction is carried out
using an aprotic organic solvent with permittivity 2.2 or more at
20.degree. C. as a reaction solvent, then the above described
solvent is removed by, for example, the method of distilling
solvent from the solution obtained by the solid-liquid separation
process, which is described in the preparation process of the
present invention, finally another desired organic solvent
substantially immiscible with water is added instead of the above
described solvent removed.
[0054] Of the above described solutions, preferable is a solution
formed by removing solid aminophosphonium chlorides having the
formula (3) from a liquid reaction product containing phosphine
oxides having the formula (2) and the above described
aminophosphonium chlorides by the solid-liquid separation process,
wherein the liquid reaction product is formed by reacting
iminophosphoranes having the formula (1) with phosphorus
oxytrichloride using as a reaction solvent an aprotic organic
solvent with permittivity 2.2 or more at 20.degree. C. which is
substantially immiscible with water and does not dissolve the
aminophosphonium chlorides having the formula (3), the above
descried phosphine oxides and phosphonium chlorides being yielded
at the same time by the above described reaction. And more
preferable is a solution formed by removing the above described
phosphonium chlorides from a liquid reaction product containing the
same by the solid-liquid separation process, wherein the liquid
reaction product is formed by reacting the above described
phosphoranes with phosphorus oxytrichloride at the above described
phosphoranes to phosphorus oxytrichloride mole ratio within 6 to
10.
[0055] As a method of water washing in the purification process of
the present invention, any method can be used as long as the method
allows the solution containing at least phosphine oxides having the
formula (2) and an organic solvent substantially immiscible with
water and water to sufficiently come in contact with each other.
Usually water washing can be carried out in such a manner that
first water is added to the above described solution, the solution
is fully stirred, and its water phase is removed after its organic
phase and water phase are separated from each other.
[0056] The amount of water used for the water washing is not
expressly restricted; however, 5 weight parts or less of water is
usually used per 1 weight part of the above described solution. The
water washing can be carried out using such an amount of water in
several installments. Preferably the water washing is carried out 2
to 5 times using 0.05 to 1.0 weight parts of water at a time per 1
weight part of the above described solution. The temperature and
duration of water washing are not expressly restricted; however,
the temperature is usually 10 to 80.degree. C., preferably 15 to
40.degree. C., and the duration is usually within 3 hours,
preferably 0.01 to 1 hour, more preferably 0.05 to 0.5 hours.
[0057] A solution of phosphine oxides having the formula (2) which
has been subjected to water washing in the above manner contains
the above described phosphine oxides of a higher purity, and it can
sometimes be used as it is for the next purpose. The above
described phosphine oxides can be obtained as solids by
concentrating to dry the solution.
[0058] According to situations, the dried solids can be further
purified. The solvent used may be completely removed from the dried
solids, or it may remain in the solids in a small amount. There
exist a trace of impurities left dissolved in such solids even
after water washing. The methods of further purifying such solids
are not expressly restricted; however, a method in which one of
hydrocarbons is added to the dried solids so as to dissolve
phosphine oxides having the formula (2) and a trace of solids
(impurities) left undissolved are removed by the solid-liquid
separation process is preferable, effective and practical.
[0059] Hydrocarbons used in this method include, for example,
saturated aliphatic hydrocarbons such as normal pentane, normal
hexane, 2,2-dimethylbutane, 2,3-dimethylbutane, 2-methylpentane,
normal heptane, normal octane, 2,3,3-trimethylpentane, isooctane,
normal nonane, 2,2,5-trimethlhexane or normal decane; alicyclic
hydrocarbons such as cyclopentane, methylcyclopentane, cyclohexane,
methylcyclohexane, ethylcyclohexane, p-menthane, bicyclohexyl or
decalin; and aromatic hydrocarbons such as benzene, toluene,
o-xylene, m-xylene or p-xylene.
[0060] Any other hydrocarbons may be used as long as they do not
hinder this method. These hydrocarbons may be used independently or
jointly. Of the above described hydrocarbons, preferable are
saturated aliphatic hydrocarbons having 5 to 10 carbon atoms, such
as normal pentane, normal hexane, normal heptane, normal octane,
normal nonane or normal decane.
[0061] The amount of these hydrocarbons used is not expressly
restricted; however, usually used are hydrocarbons 0.5 to 50 times
as heavy as the above described dried solids, preferably
hydrocarbons 1 to 20 times as heavy as the above described dried
solids. When hydrocarbons are added to the above described dried
solid to dissolve phosphine oxides having the formula (2), the
temperature and duration in the above operation are not expressly
restricted; however, the temperature is usually 10 to 100.degree.
C., preferably 20 to 50.degree. C., the duration is usually 0.1 to
3 hours, preferably 0.5 to 2 hours. After that, the solid left
undissolved in the above described hydrocarbon solution is removed
by the solid-liquid separation process. The solid-liquid separation
can be conducted using any methods; however, general-purpose
methods such as filtration, centrifugation and decantation are
usually used. Of the above methods, filtration is most preferable.
The undissolved solid can be washed with hydrocarbons, and the
washings may be combined to the filtrate.
[0062] Thus, a solution containing phosphine oxides having the
formula (2) of a extremely high purity can be obtained. If needed,
the above described solution can be concentrated to dry to obtain
the above described phosphine oxides as a solid.
[0063] The present invention will be further illustrated by the
following examples; however, these examples are intended to
illustrate the invention and are not intended to limit the
invention to the specific examples.
EXAMPLE 1
[0064] Under a nitrogen atmosphere, 54.3 g (305 mmol) of
iminotris(dimethylamino) phosphorane, which is iminophosphorane
having the formula (1) whose R is a methyl group, and 130 g of
dried o-dichlorobenzene (with permittivity 6.80 at 20.degree. C.)
were prepared in a 300 ml glass reactor vessel. Then, a liquid
mixture of 7.67 g (50.0 mmol) of phosphorus oxytrichloride and 16.3
g of dried o-dichlorobenzene (the concentration of phosphorus
oxytrichloride was 32 weight %) was added drop by drop over 30
minutes while stirring the mixture and controlling the internal
temperature to be kept at 20.degree. C. The mole ratio of
iminotris(dimethylamino)phosphorane to phosphorus oxytrichloride
was 6.1. At this time, part of the liquid reaction product was
taken as a sample.
[0065] A .sup.31P-NMR quantitative analysis was conducted using
dimethyl sulfoxide deuteride as a solvent and tri-normal-butyl
phosphate as an internal standard compound (hereafter, yield and
purity were analyzed in this manner). The analysis shows that
almost no tris[tris(dimethylamino)p- hosphoranylidenamino]phosphine
oxide, which is phosphine oxide having the formula (2) whose R is a
methyl group, was formed. Then, the temperature of the liquid
reaction product was raised to 40.degree. C. and the reaction was
continued for 24 hours, as a result of which the above described
phosphine oxide was obtained in a reaction yield to phosphorus
oxytrichloride of 83.6%.
[0066] This result, together with the results of examples 2 to 7
and comparative examples 1 to 4 where reaction was carried out
using respective solvents other than o-dichlorobenzene whose
permittivity is 2.2 or more or less than 2.2 at 20.degree. C., is
shown in Table 1. Table 1 shows that there existed a big clear
difference in reaction rate between the solvents with permittivity
2.2 or more at 20.degree. C. and with permittivity less than 2.2 at
20.degree. C., in addition, the use of the solvents with
permittivity 2.2 or more at 20.degree. C. is very effective in
increasing the reaction yield of the object compound.
EXAMPLES 2-7
COMPARATIVE EXAMPLES 1-4
[0067] The reaction was carried out exactly in the same manner as
example 1, except that various types aprotic organic solvents shown
in Table 1 were used instead of o-dichlorobenzene.
1 TABLE 1 Aprotic Organic Permit- Reaction Examples Solvent tivity
Yield (%) Example 2 Benzene 2.28 81.9 Example 3 Chloroform 4.81
81.3 Example 4 Ethyl Acetate 6.08 85.4 Example 1 o- 6.80 83.6
Dichlorobenzene Example 5 Tetrahydrofuran 7.60 89.7 Example 6
Nitrobenzene 34.9 92.2 Example 7 Acetonitrile 37.5 91.6 Comparative
Hexane 1.89 55.6 Example 1 Comparative Petroleum Ether 1.85-1.95
58.1 Example 2 Comparative 1-Hexene 2.06 57.5 Example 3 Comparative
Decalin 2.19 51.9 Example 4 Note: Permittivity represents
permittivity at 20.degree. C.
EXAMPLE 8
[0068] Under a nitrogen atmosphere, 15.4 g (100 mmol) of phosphorus
oxytrichloride and 154 g of dried o-dichlorobenzene were prepared
in a 500 ml glass reactor vessel. Then, 116 g (651 mmol) of
iminotris(dimethylamino) phosphorane was added drop by drop over 1
hour while stirring the mixture and controlling the bulk
temperature to be kept at 70.degree. C. or lower. The mole ratio of
iminotris(dimethylamino- )phosphorane to phosphorus oxytrichloride
was 6.5. After completing the addition of
iminotris(dimethylamino)phosphorane, stirring was continued at
70.degree. C. for 1 hour, so as to obtain a white slurry. Part of
this liquid reaction product was taken as a sample and a
quantitative analysis was conducted. The analysis shows that the
reaction yield of
tris[tris(dimethylamino)phosphoranylidenamino]phosphine oxide was
85.4%.
[0069] After the reaction, the above described white slurry was
filtered, the solid was washed with a small amount of
o-dichlorobenzene, and 266 g of filtrate and washings was obtained.
The filtrate and washings was taken in a 300 ml separating funnel,
31.9 g of water (0.12 times as heavy as the filtrate and washings)
was added, and water-washing was conducted of the filtrate and
washings while intensely shaking the separating funnel so that both
of the o-dichlorobenzene phase and the water phase were
satisfactorily contacted with each other, then the separating
funnel was allowed to stand still to separate the o-dichlorobenzene
phase and the water phase from each other, and each phase was
collected as a sample. This water-washing operation was carried out
another two times.
[0070] A quantitative analysis was conducted of the
o-dichlorobenzene phase obtained, and the analysis shows that
iminotris(dimethylamino)phosp- horane, which was left unreacted
before water-washing, was decreased to an amount less than the
limit of detection and the amount of by-products was also
drastically decreased compared with that before water-washing.
Then, the o-dichlorobenzene phase was concentrated to dry at
80.degree. C., 10 mmHg to obtain 50.5 g of white solid.
[0071] The purity of
tris[tris(dimethylamino)phosphoranylidenamino]phosphi- ne oxide in
the solid was 95.4 weight % and the isolation yield was 83.3%. As
described above, the above described phosphine oxide was obtained
with little loss and with a satisfactorily high purity only by
water-washing the filtrate and washings after filtrating the liquid
reaction product.
[0072] In order to further purify the above described phosphine
oxide, the obtained solid was dissolved in normal hexane which was
10 times as heavy as the solid while stirring the solution over 40
minutes. After that, the solid left undissolved was filtered, and
the undissolved matter was washed with a small amount of normal
hexane. The undissolved solid was about 1.9 g in weight after being
dried. The filtrate and washings obtained was concentrated to dry
at 60.degree. C., 10 mmHG and subjected to drying operation at
80.degree. C. for 5 hours under the flow of nitrogen.
[0073] As a result, 48.5 g of white solid was obtained, and its
isolation yield was 83.1% and its purity was increased to as high
as 99.2 weight %. Then, the chlorine ion content of the solid was
measured by the potentiometric titration method using a chlorine
ion electrode (hereafter the same as above). The measured value was
43 ppm.
COMPARATIVE EXAMPLE 5
[0074] The reaction was carried out in accordance with the process
described in the literature by G. N. Koidan et al.
[0075] Under a nitrogen atmosphere, 53.5 g (300 mmol) of
iminotris(dimethylamino) phosphorane and 200 ml of dried petroleum
ether were prepared in a 300 ml glass reactor vessel (the
concentration of the above described phosphorane was 29 weight %).
Then, a liquid mixture of 7.67 g (50.0 mmol) of phosphorus
oxytrichloride and 25 ml of dried petroleum ether (the
concentration of phosphorus oxytrichloride was 32 weight %) was
added drop by drop over 30 minutes while stirring the mixture and
controlling the bulk temperature to be kept at 20.degree. C.
[0076] The mole ratio of iminotris(dimethylamino)phosphorane to
phosphorus oxytrichloride was 6.0. At this time, part of the liquid
reaction product was taken as a sample, and it was found that
almost no object compound was formed. Then, the liquid reaction
product was heated at its reflux temperature (about 40.degree. C.)
and the reaction was continued. The yields after 24 hours and 48
hours were 59.8% and 73.0%, respectively. As is apparent when
compared with the results of examples 1 to 7, in the process in
accordance with the description in the above described literature,
both reaction rate and yield were low.
COMPARATIVE EXAMPLE 6
[0077] Purification was carried out using the liquid reaction
product obtained in accordance with the process described in the
literature by G. N. Koidan et al. (the liquid reaction product
obtained in comparative example 5) in accordance with the
purification process described in the above described
literature.
[0078] The white slurry of petroleum ether obtained from the
reaction in comparative example 5 was filtered, the solid left
after the filtration was washed twice with 50 ml of petroleum
ether, and the obtained filtrate and washings was concentrated to
dry at 30.degree. C., 150 mmHg. As a result, 21.5 g of faintly
yellowish white solid was obtained. When 6.0 g of petroleum ether
(only 28 weight % of the solid) was added, the solid was almost
completely dissolved in the petroleum ether at 25.degree. C. The
solution thus obtained was filtered, and the filtrate was cooled so
as to crystallize. However, a very small amount of crystallization
was observed only after the temperature of the filtrate was reduced
to -10.degree. C.
[0079] The filtrate temperature was further reduced to -20.degree.
C., and a certain amount of crystallization was finally achieved.
The filtrate thus obtained was immediately filtered by using a cold
filtration system at -20.degree. C., the filtered crystal was
washed with about 3 g of petroleum ether cooled at -30.degree. C.,
and 5.89 g of white crystal was obtained. This crystal was
tris[tris(dimethylamino)phosphoranylidenamino]- phosphine oxide
with purity 98.2 weight %; however, the yield was only 20.0% and
the concentration of chlorine ion was as high as 640 ppm.
[0080] As described above, even though recrystallization was
carried out using a small amount of solvent, an extremely low
temperature was required; and moreover, the yield of crystal was
very low.
COMPARATIVE EXAMPLE 7
[0081] The reaction was carried out exactly in the same manner as
comparative example 5, except that the amount of
iminotris(dimethylamino)- phosphorane used was 57.9 g (325 mmol)
and the reaction time at the reflux temperature of the liquid
reaction product (about 40.degree. C.) was 30 hours. And the
purification was carried out at -20.degree. C. exactly in the same
manner as comparative example 6. The mole ratio of
iminotris(dimethylamino)phosphorane to phosphorus oxytrichloride
was 6.5 (in excess of that stoichiometrically required). The yield
after the reaction was 75.3%, and apparently the reaction rate was
increased compared with the result of comparative example 5 only
because the amount of the above described phosphorane used was
increased.
[0082] After the recrystallization, 6.57 g of white crystal was
obtained. The purity of the crystal was 94.1 weight % and the yield
was 20.7%. Even after the operation of recrystallization, the
purity was not satisfactory. In the crystal, about 2 weight % of
iminotris(dimethylamino- )phosphorane as well as unknown impurities
was observed. The above described phosphorane used in excess of
that stoichiometrically required in the reaction could not be fully
removed by this process, as a result, it remained in the object
crystal deposited after the operation of recrystallization.
COMPARATIVE EXAMPLE 8
[0083] The reaction was carried out exactly in the same manner as
comparative example 5, except that the reaction time at the reflux
temperature of the liquid reaction product (about 40.degree. C.)
was 40 hours. The yield after the reaction was 70.2%. The white
slurry of petroleum ether obtained was filtered, and the solid was
washed twice with 50 ml of petroleum ether. To the filtrate and
washings obtained, water 0.12 times as heavy as the filtrate was
added, and water-washing was conducted of the filtrate and washings
while intensely shaking the mixed solution so that both of the
petroleum ether phase and the water phase were satisfactorily
contacted with each other, then the mixed solution was allowed to
stand still to separate the petroleum ether phase and the water
phase from each other, and each phase was collected as a sample.
This water-washing operation was carried out another two times.
[0084] When a quantitative analysis was conducted of the petroleum
ether phase obtained, it was revealed that almost no object
compound, that is,
tris[tris(dimethylamino)phosphoranylidenamino]phosphine was
contained in the petroleum ether phase. Then, the same analysis was
conducted of the water phase. The analysis revealed that 99 weight
% of the object compound contained before water washing, together
with by-products and iminotris(dimethylamino)phosphorane left
unreacted, was contained in the water phase.
EXAMPLE 9
[0085] The reaction and the water washing were carried out in the
same manner as example 8, except that dried toluene was used
instead of o-dichlorobenzene. The toluene phase obtained after the
water washing was concentrated to dry at 60.degree. C., 50 mmHg.
The solid obtained was the object compound with purity 93.5 weight
%, and its yield was 82.9%.
EXAMPLE 10
[0086] The reaction and the water washing were carried out in the
same manner as example 8, except that dried 2,4-dichlorotoluene was
used instead of o-dichlorobenzene. The 2,4-dichlorotoluene phase
obtained after the water washing was concentrated to dry at
90.degree. C., 10 mmHg. The solid obtained was the object compound
with purity 96.1 weight %, and its yield was 82.4%.
EXAMPLE 11
[0087] The reaction and the water washing were carried out in the
same manner as example 8, except that dried chlorobenzene was used
instead of o-dichlorobenzene, that the amount of
iminotris(dimethylamino)phosphorane used was 112 g (628 mmol), of
that the bulk temperature at the time of dropping the above
described phosphorane was controlled to be kept at 60.degree. C. or
lower and that the reaction temperature after the dropping was
60.degree. C. The mole ratio of iminotris(dimethylamino)phos-
phorane to phosphorus oxytrichloride was 6.3. The chlorobenzene
phase obtained after the water washing was concentrated to dry at
80.degree. C., 60 mmHg. The solid obtained was the object compound
with purity 94.1 weight %, and its yield was 67.3%.
EXAMPLE 12
[0088] The reaction and the water washing were carried out in the
same manner as example 11, except that the amount of
iminotris(dimethylamino)p- hosphorane used was 120 g (673 mmol).
The mole ratio of iminotris(dimethylamino)phosphorane to phosphorus
oxytrichloride was 6.7. The solid obtained by concentrating to dry
the chlorobenzene phase after the water washing was the object
compound with purity 95.9 weight %, and its yield was 80.7%.
EXAMPLES 13, 14
[0089] The solid obtained by concentrating to dry o-dichlorobenzene
phase, which was obtained by carrying out the reaction and the
water washing exactly in the same manner as example 8, was purified
in the same manner as example 8, except that normal heptane 15
times as heavy as normal hexane used in example 8 (example 13) and
normal octane twice as heavy as normal hexane used in example 8
(example 14) were used. The yields of the object compound obtained
were 83%, almost the same in both cases, and the purities were 98.9
weight % and 97.6 weight % in the order described above.
EXAMPLE 15
[0090] The reaction and the water washing were carried out exactly
in the same manner as example 8, except that the amount of the
water used at a time was 0.20 times as heavy as the filtrate and
washings. The solid obtained by concentrating to dry
o-dichlorobenzene phase after the water washing was the object
compound with purity 96.5 weight %, and its yield was 79.9%.
[0091] As described above, according to the present invention, in
the process for preparing phosphine oxides having the formula (2)
which comprises reacting iminophosphoranes having the formula (1)
with phosphorus oxytrichloride, purification can be carried out in
a simpler and easier way, the above described phosphoranes can be
used in excess of that stoichiometrically required, and the above
described phosphine oxides can be obtained with higher purity and
in a higher yield in an industrially more realistic way.
* * * * *