Note: Descriptions are shown in the official language in which they were submitted.
2 ~
HOE 89/H 032
Process for the preparation of pure cyclic phosphoric
acid diaryl e~ter~
The present invention xelates to a process for the
-_ preparation of pure cyclic phosphoric acid diaryl esters.
S Cyclic phosphoric acid diaryl esters are being incor-
porated to an increasing extent into plastics as
stabilizers and additives for improving the clarity of
thermoplastics and into photographic ystems as color
stabilizers.
The cyclic phosphoric acid diaryl esters used for this
purpose must be employed in a pure, colorless state.
...
According to DE-C-2,212,660 or EP-s-68,326, cyclic
binaphthyl-phosphoric acid esters or bisphenol-phosphoric
acid esters can be prepared by the action of POC13 on the
corresponding binaphthyl-Z,2'-diols or bisphenyl-2,2'-
diols in the presence of basic substances, in particular
pyridine, in stoichiometric amounts as an acid-binding
agent. The cyclic phosphoric acid diaryl ester is then
isolated in the pure form by further purification steps.
. ' .
A disadvantage here i8 the large amount of acid-binding
agents to be employed, which leads to undesirable ef-
fluents during reprocessing.
,' '
The ob~ect was therefore to provide a process for the
preparation of pure cyclic phosphoric acid diaryl esters
which operates with high yield~ and in a simple, eco-
nomical manner and with which no undesirable effluents
b are obtained.
A ~imple process has now been found for the preparation
. of pure cyclic phosphoric acid diaryl esters from POHal3
and a bis-phenol derivative of the formula I
-- .
,~
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,.: , ' , .', , .. ., , .' , ':.. ' .; .''~ . -
: . . .- : : -
,. :.
-
:: .: . - - ;
: . , : : -
,~:...... , . ~ .
~, .
,.:
., .
2 ~ . 7S,3.
-- 2 _
Rl
R~H
~ H
; in which Rl to R4 can be alkyl having 1 to 18 carbon
atoms, an aryl radical having 6 to 10 carbon atom~,
arylalkyl having 1 to 3 carbon atom~ in the chain,
halogen or H, and in which A is a direct C-C bond or an
alkylidene group of the formula
. I
. R, - C - R_
o
in which R5 and R~ can be alkyl having 1 to 12 carbon
atoms, an optionally substituted cyclic sys~em having a
total of 5 to 12 carbon atoms or H,
or from a dihydroxy-dinaphthyl derivative of the
formula II
l2 ll
R ~ 3H
¦ II
. R
R7 R3
'
. in which R~ to R4, R7 and R3 can be alkyl having 1 to
18 carbon atoms, halogen or H, which comprises
a) employing POHal3 in a stoichiometric excess of O to
. 500 mol~,
:
b) carrying out the reaction in the presence of a
~. ' .
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- ,.~ . . ~ . , :.
.. - - . ., .:
, . ' ~
..
- . .
:, :
203~7~
cataly~t at temperatures of 50 to 180C over a
period of 1 to 24 hours,
:
c) removing excess POHal3 after the reaction,
d) diluting the reaction mixture with 0.1 to 10 g of
glacial acetic acid per g,
e) hydrolyzing the reaction mixture diluted with
glacial acetic acid with 1 to 4 mol of water,
calculated on the number of moles of POHal3 reacted,
and
10 f) filtering off the cyclic phosphoric acid diaryl
ester deposited as crystals, of the formula III
,. ~ .
;.
R~o
R ~ III
J ~'1 "'~
. in which A, R1~ R2, R3, R~, R5 and R8 have the meaning given
in the case of formula I, ::
or the cyclic pho~phoric acid diaryl ester of the
`:: formula IV
Rz ~1
\p ~ IV
7 ~a
: in which R1~ R2, R3, R4, R~ and RA have the meaning given
.~ in the case of formula II. ~ -
, . ~
:.
Qj~
., .
. . :' .~
:,,:~::: .. : :,, :''' -': .' :,', "' :' ' ' ' , . .. , . '' '':'.' . . ... '
- 4 ~
: ~he proce~s according to the invention can further~ore
optionally also be de~igned such that
aa) POC13 or POBr3 is employed as the POHal3;
bb) nitrogen bases, such as 4-dimethylaminopyridine or
N,N-dimethylformamide, organopho~phorus compounds,
such as trioctylphosphine oxide or triphenylphos-
phine oxide, or metal chlorides, such a~ aluminum
chloride or magnesium chloride, are employed as the
catalyst;
..
cc) the hydrolysis is carried out at a temperature of 10
to 140C, in particular 60 to 120C;
dd) after removal of the glacial acetic acid, the cyclic
phosphoric acid diaryl ester is treated at temper-
atures of 40 to 120C, in particular at 100C,
preferably under reduced pressure, to remove the
residual glacial acetic acid;
ee) the glacial acetic acid removed i8 worked up by
: distillation;
.: ff) the reaction is carried out under an increased
pressure of up to 3 bar;
.:
: gg) 2,2'-dihydroxy-1,1'-dinaphthyl (CAS No. ~602-09-5])
is reacted with POCl3;
~; hh) 2,2'-dihydroxybiphenyl (CAS No. ~1806-27-7]) is
reacted with POCl3;
.: , .
ii) after removal of the glacial acetic acid, the cyclic
~. phosphoric acid diaryl ester is washed with an
organic solvent, such as acetone, hexane or
. methanol.
..
Using the process according to the invention it is now
~ '
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. - . . . . - - ,. .- ~. .
.,, ~ . -
. . ~ . .
:- .
.. . . . . . . .
..... . .
203~ 7~
possible to avoid the disadvantages of known proce~ses,
such as, for example, the removal of by-products by
extraction by means of large amounts of solvents, the
occurrence of caking, losses in yield and the low product
S purity.
The use of acetic acid in the hydrolysis has proved to be
particularly advantageous here, ~ince the starting
materials are very readily soluble but the products are
in general relatively sparingly soluble in this solvent
and are thus obtained directly in a crystalline form
which can easily be filtered.
The use of acetic acid in the hydrolysis has proved to be
particularly appropriate in the case of 2,2'-biphenyl-
~` ylenephosphoryl chloride (CAS No. ~52258-06-7]), because
the end product crystallizes in a high yield and a high
purity, even though tarry by-products, in particular
oxidation products of the phenol, are entrained into the
process with the raw material.
: ':
This finding is all the more surprising since it was
known that
~P ~
reacts by itself, that is to say without addition of
~ water, to form
.'.: .
3 ~ - OH
and acetyl chloride, cf. HOUBEN-HEYLs "Methoden der
Organischen Chemie~ (Nethods of Organic Chemistry),
E2, (1982), page 503.
: J
.
::.. ~: .. : : :. -
. ~, ... . .. .
,.. : .:,. - . - . .: .
. ::.,:: :. ~ - - ,
- 6 2030~ 7y
The registration numbers (CAS No.) quoted in Chemical
Ab~tracts are also given for the individual components
for unambiguous characterization.
.
The cyclic phosphoric acid diaryl esters according to the
invention can be converted in a solvent, such as water,
methanol or dioxane, into the corresponding alkali metal
salts using alkali metal ~alts, in particular NaOH or
; Na2CO3, or into the ammonium salt by gaseous ammonia if
the corresponding salts have to be employed during
further processing.
Only small amount~ of catalyst are employed according to
the invention. According to the prior art, stoichio-
metrically large amounts of acid-binding substances, such
as, for example, pyridine, in inert solvents are used.
During the hydrolysis, the pyridine ~alt of the cyclic
phosphoric diaryl ester is formed first, and then has to
be neutralized by a corresponding foreign acid and in
this way leads to an undesirable salt loading in the
effluent.
The proces~ according to the invention is illustrated
further by the examples.
Comparison Example 1
(~Phosphorus and Sulfur~, Gordon and Breach Science
Publishers, Inc., USA, Volume 8 (1980) page 144)
,'.
i- 25 A solution of 30 g (0.16 mol) of 2,2'-dihydroxybiphenyl
(CAS No. ~1806-27-7~ in 200 ml of anhydrous ether is
added dropwise to a solution of 35 g (0.23 mol) of POC13
and 26 g (0.33 mol) of pyridine in 200 ml of anhydrous
ether. After the pyridine hydrochloride has been filtered
- 30 off, the solvent is removed in vacuo and the residue is
; recrystallized from ligroin (100 - 125C).
; Yield of 2,2'-biphenylylenephosphoryl chloride: 90 % of
;~ theory.
,~
: . ~
.. :
~;''
~.,
'""'1 '" ' ' ~'.'.' ~" ' ' ' 1.
2 ~ 7 ~
- 7 -
200 ml of concentrated hydrochloric acid are added in
- portions to a ~olution of 10 g of 2,2~-biphenylylenephos-
phoryl chloride (CAS No. [52258-06-7]) in 200 ml of
water, while stirring. ~he 2,2~-biphenylyenephosphoric
S acid (CAS No. [35227-84-0]) which has precipitated i~
filtered off, washed with concentrated hydrochloric acid
and dried in vacuo over ROH.
; Yield: 80 S of theory; melting point: 262 to 263C, with
decomposition. -
. .
Comparison Example 2
'~ ~
0.5 ml of N,N-dimethylformamide i8 added to 93.1 g of
2,2~-dihydroxybiphenyl (CAS No. tl806-27-7]) and 153.3 g
of POCl3 and the mixture i8 kept at the boiling point
under reflux for 10 hours. Unreacted POC13 i8 removed
under a water pump vacuum and the crystalline residue is
taken up in 200 ml of toluene.
, The solution i8 added dropwise to 1 1 of half-
- concentrated HCl, while stirring vigorously. An oil,
s which solidifies on heating and blocks the stirrer, is
deposited at the phase boundary. 111 g of brown-colored
; product (2,2'-biphenylylenephosphoric acid (CAS No.
[35227-84-0]) i8 obtained by co~minution of the solid,
; filtration, washing and drying.
Yields 89.4 % of theory; melting point: 262C, with
decomposition.
.''',
Example 3
i '
1464 g of 2,2'-dihydroxybiphenyl (CAS No. [1806-27-7])
and 2412 g of POC13 are kept at the boiling point under
~i reflux for 10 hours with 0.5 g of N,N'-dimethylformamide.
; 30 After the unreacted POCl3 has been stripped off under a
water pump vacuum, 1000 ml of glacial acetic acid are
` added to the reaction mixture at 80-C and 200 m} of water
are added dropwi~e at a tempera~ure of 80-C in the course
of 40 minute~, while stirring. Crystalline 2,2~-biphenyl-
ylenephosphoric acid (CAS No. [35227-84-0]) precipitates
. .,
., .
~ A ., .
- 8 - 2 ~30~ ~9
out, HCl being evolved. After cooling to room temper-
ature, the crystal slurry~ is filtered off with suction,
washed with 2 x 200 ml of acetone and dried. 1864 g of
crystals are obtained.
Yield: 95.5 3 of theory; melting point: 273C (without
decomposition).
31P-NMR (D20) 5.6 ppm
j:
Example 4
r
268 g of 2,2'-dihydroxy-1,1'-dinaphthyl ~CAS No. [602-09-
5]), 550 g of POC13 and 0.5 g of N,N-dimethylformamide
are reacted in accordance with Example 3.
500 ml of glacial acetic acid are added to the reaction
mixture and 25 ml of H2O are added dropwise at a temper-
ature of 75C in the course of 15 minutes, while
stirring.
234 g of colorless crystals are obtained (binaphthylyl-
enephosphoric acid (CAS No. t35193-63-6]) are obtained.
Yield: 72 % of theory; melting point: 202C.
, 31p_NNR (CDCl3) 10-8 ppm-
Example 5
~,......................................................................... .
138 g of 3,3~,5,5~-tetra-tert.-butyl-2,2~-biphenyldiol
(CAS No. t6390-69-8]), 130 g of POCl3 and 1 g of tri-
,- octylphosphine oxide are reacted in accordance with
; Example 3. 150 ml of glacial acetic acid are added to thereaction mixture and 8.5 ml of H2O are added at a temper-
ature of 130C under pressure in the course of 10 min-
utes, while stirring.
131 g of colorless crystals (cyclic phosphoric acid
diaryl ester) are obtained.
Yield: 82.4 % of theory; melting point: 160 to 170C.
3lP-NMR (CDCl3)-l-l ppm-
; Example 6
,.
~,...
100 g of 2,2'-methylene-bis(4-chlorophenol) (Cas No.
~" ~
' .
. ~ . ,, . " ,. , ... , , ., . , . , ., . .. , . .. .... ..... .... ~ .. .... . .. .. .. . ... . . .. . . .. .
g 2~3~-~7~
[97-23-4]), 171 g of POC13 and 0.1 g of N,N-dimethyl-
formamide are reacted in accordance with Example 3~
180 ml of glacial acetic acid are added to the reaction
mixture. 9 ml of H20 are added dropwi~e to the suspension,
S formed on ~tirring, at a temperature of 70-C in the
course of 10 minutes. The product i8 filtered off with
suction and then ~uspended in n-hexane. After filtration
with suction and drying, 84 g of product are obtained
(cyclic phosphoric acid diaryl ester).
; 10 Yield: 75.0 ~ of theory; decomposition point: 290-C.
3lP-NMR (C5D~) 13.6 ppm-
~,
Example 7
100 g of 2,2'-methylene-bis(4-methyl-6-tert.-butyl-
phenol) (CAS No. ~119-47-1], 135 g of POC13 and 0.2 g of
lS N,N-dimethylformamide are reacted in accordance with
Example 3.
k: 60 ml of glacial acetic acid are added to the reaction
mixture and 6.5 ml of H2O are added dropwise at a temp-
erature of 60-C in the course of 10 minutes, while
;; 20 ~tirring.
34 g of colorless crystals are obtained (cyclic pho~-
' phoric acid diaryl ester).
Yield: 33 % of theory; melting point: 297 to 301C.
3lP-NMR (C~D5) 12.1 ppm-
Example 8
''
123 g of 2,2'-methylene-bis(4,6-di-tert.-butylphenol)
(CAS No. tl4362-12-0]), 210 g of POBr3 and O.S g of N,N-
dimethylformamide are reacted in accorance with
E~ample 3.
150 ml of glacial acetic acid are added to the reaction
mixture and 8.5 ml of H2O are added dropwise at a temper-
ature of 60-C in the course of 10 minutes, while
stirring.
48 g of colorless crystals are obtained (cyclic phos-
`~ 35 phoric acid diaryl ester (CAS No. ~106396-29-6]).
:,
~, . . .
r
lO- 20~79
Yield: 34 % of theory; melting point: 272 to 275C.
31P-NMR ( C61)6 ) 1 1 . 4 ppm .
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