Note: Descriptions are shown in the official language in which they were submitted.
0~
The present invention relates to an improved process
for the preparation of halogenoalkyl-substituted oxiranes
from halogenoalkyl-substituted olefins and percarboxylic
acids~
Halogenoalkyl-~ubstituted oxiranes are used in the
field of lacquers and plastics and as organic intermediate
products.
It is known to prepare chloroalkyl-3ubstituted oxi-
ranes from the corresponding olefins by the chlorohydrin
process. Thi~ process has the disadvantage that undesired
chlorinated by-product~ and waste salts which pollute the
environment are formed (Ullmanns Encyklopadie der technischen
Chemie (Ullmanns Encyclopaedia of Industrial Chemistry), vol-
ume 10, page 565, left-hand column, line 1 et ~eq., in
p~rticular 3. 13-15; and DAS (German Published Specification~
19543,174, column 2, line 15 et ~eq., in particular 3. 32-35).
It i8 al80 frequentl~ icult definitively -to pre-
pare a single reaction prod,~ct by the,chlorohydrin method.
Thu~, th~ reaction o~ 4-chlorobut-2-ene,wi,th hypochlorous acid
zo l~ads to a mixture of two products, which may be characterised
by the follcwing formulao:
OH Cl Cl Cl 0~ Cl
CH3-CH-CH CH2 and CH3-CH-CH-CH2 ','
~ Accordingly, subsequent dehydrohalogenation o~ thi~
mixture u~ing a',bas~ gives a mixture of two i~omeric oxiranes,
as the ~ormulae below illustrate (DAS (German Published
Specification) 19056,596, column 1, line 53 to column 2, 3-43):
~ ~1 Cl O - - '
/ \
CH~-C~CH-~, and CH3-CH-SH-CH2
Furthermore, it ls known to convert olefins into the
corresp~nding oxlr~n~ with the aid of a percarboxylic acid.
.
~213~
(N. Prile3chajew, Ber. dt3ch. Chem. Ges. 42, 4,811 (1909))
This reaction is an electrophilic attack of the oxi-
dislng agent on the olefin. (K. D. Bingham, G. D. Meakins
and G. H~ Whitham, Chem. Commun. (1966, pages 445 and 446).)
For this reason, the reactivity o~ the ole~in decreases with
decr~a~lng nucleophilicity of the double bond. Electro-
negative ~ubstituents in the a~position relative to the
C=C double bond thus impede the epoxidation. (S. N. Lewis
in R. Lo Augu~tin, "Oxidation", volume I, page 227, in par-
-ticular page 227, 3. 9-13, Marcel Dekker, New York (1969).)
Halo~enoalkyl-substituted ole~ins there~ore cannot be epoxi-
dised with percarboxylic acids without problems. As a
result of the low reactivity of their double bond, high
temperatures and long reaction times are necessary, which
gives ris~ to the formation of unde~ired by-products, such as
dihydroxy and hydroxyacyloxy derlvat~ve~ of the starting mat-
erials. (S. N. Lewis in R. L. Augu~tln, "Oxidat1on'1, volume
I, page 233, in particular 3. 6-11, Marcel Dekker, New York
1969). .,:
.
The ~tructure and method of preparat1on of the percarb-
oxylic aci~ usedis thusof great importance, in p~rticular with
re~ard to the nature and procedure o~ the reac~ion between a
halogenoalkyl-aub~t1tuted olefin and a percar~oxylic acid.
~ A~ n~wn, lower ~liphatic percarbo~ylic acids can
.
be prcpar~d from a carboxylic acid and hydrogen peroxide in an
equill~rium ~e~ction according to equation (1). tD. Swern,
in nOrgenla Peroxid~s1', volume 1, page 619 Wiley Interscie~se
1971)
RCOON + N22 ~ RCOOOH ~ H20 (1~
~xcept ~o~ when relatively strong carboxylic acids are
u~ed, ~uch as formic acid and trifluroacetic acid, strong
~ . .
~ - 3 -
~ 2~ ~ ~ 8
acids, ~uch a~ sulphuric acid, p-toluenesulphonic acid and
others, are required as a catalyst for rapid e~tablishment of
the equilibrium (S. N. Lewis in R. L. Augustin "Oxidation",
volume I, pRge 216 ("C. Peracids"), Marcel Dekker, New York
1969). However, the reaction of olefins with, for example,
peracetic acid prepared by thi~ method did not lead to oxi-
rane_ but to ~-glycols and hydroxyacetate~ (J. Boseken,
W. C. 5mit and Gaster, Proc. Acad. Sci. A~sterdam, 32
377-383 (1~29)-) The mineral acid present in the reaction
mixture catalyse~ the splitting-open of the oxirane pri-
marily formed tD. Swern "Organic Peroxide~", Wiley
Interscien~e 1971, volume 2, page 436), which can lead to oxi-
rane losse~Q, especlally in the case o~ ole~ins which are
9ioW to react, quch as halogenoalkyl-substituted olefins, for
the reaction of which high temperatures and long reaction
times are nece~sary.
Per~ormic acid can ~e prepared from hydrogen per-
oxide and ~ormic acid without an additional catalyst (S. N.
Lewi~ in R. L~ Augustin, "Oxidation", volume I, page 217,
~irst~paragraph, Marcel Dekker, New York 1969). - However,
th~ reaction of a-chloroalkyl-~ubstituted olefins with thi~
mineral acid-~ree percarbo~ylic acid al~o gave the correspon-
ding epoxide onlr in low yialds. A performic acid
prepared ~rom 9~% ~tr~ngth formic acid and 85% strength hydro-
gen peroxide ~a8 thus uQed for the epoxidation of 3,4-di- -
chlorobut-l-ene. A~ter a reaction time of five hours at
60&, 2~(1,2-dichloroethyl-)oxirane was obtained in ~0~ yield
(E. G. E~ Hawkln~, J. ~hem. Soc., 1959 pages 248 to 256, in
par*icular page 250, li~e 19).
~ A proce~ ~or the preparation of aliphatic chloro-
epoxides by reacting an allylchloro~ydrocarbon, which has a
~_L~ 4 ~
:
,
0~8
chlorine atom in the ad~acent position to the double bond,
with an organic per-compound which i3 free from inorganic
impurities has been disclosed recently (DAS (German Published
Speci~ication) 1,056,596). The per-compounds usedin this
proces3 are ~'pure peracetic acid, perpropionic acid or acet-
aldehyde monoperacetate mixed with acetaldehyde and/or
acetone". (DAS (German Published Specification) 1,056,596,
column 10, lines 32-35.) The epoxidation, according to the
process of DAS (German Published Specification) 1,056,596, of
olefins, which are chloro-substituted in the allyl position,
using acetaldehyde monoperacetate gives the corresponding oxi
ranes in yield~ of between 17% and 56%, relative to the per-
compound, depending on the olefin. (DAS (German Published
Spocification) 1,056,596, colu~n 5 to 7, line 35 et seq~,
Example 1, 3, 4 and 6).
The peracetic acid and perpropionic acid used in this
proces$ for the epoxidation is employed in solution in an
in~rt organic solventO As described at another point, typi-
cal 1nert solvents which can be employed in this process are,
inter alla, acetone, ethyl acetate, butyl acetate and dibutyl
ether (U.S. P~tent 3,150,154, column 3, line 1~-3)~
Al~ylchlorohydrocarbons can be epoxidised with the per-
acid~ prep~r~d according to th~ process of DAS (German
Publish~d ~pecification) 1,056,596; however, the yields of
oxir~n~ ~r~ low; the peracid con~ersion is incomplete. In
~he ~ les 1ndicated it is only about 90% and the purity of
tho oxira~e~ isolated i8 inadequate for industrial use.
- ~ .
Thu8g ~h~ o~ida~ion of 3-chloro-1-butene with a solution of
.. ..
pera~t~c~-a~d in acaton~ is described in DAS ~German Pub-
li~he~ ~peG~ atlon) 1,056,596 in Example 5, column 7, line
5 at 8~q. ~.: A~ter a reaction time of ten hours, the peracid
~ - 5 -
:
' " .
conversion is 91%. The oxirane i9 isolated in 68% yield
with a purlty of 90.5~0
The pr~paration of 3,4-dichloro-1,2-epoxybutane by
reacting 3,4-dichloro-1-butene with peracetic acid in acetone
is described in British Patent Specification 784l620, in
Example VII, page 7, line 5 et seq. According to this pre-
paration, the peracid conversion i8 89% and the yield of
epoxide is 75%. The purity of the epoxide is given as
93.3%. An account of the epoxidation of an olefin with
perproplonic acid is also given in British Patent Speci~ica-
tion 784,620, in Example IX, page 7, line 85 et seq.
According to this epoxidation, after reacting crotyl chloride
with a solution of perpropionic acid in ethyl propionate7
l-chloro-2,3-epoxybut~ne was obtained in 56% yield. The
peracid conver~ion was 90~.
In contrast, it has now been found that halogenoalkyl-
sub~tituted oxirane~ can be prepared in high yields and high
purity from halogenoalkyl-substituted olefins and percarboxylic
acids in organic 301ution by a procb~s in. which a chloroalkyl-
&ubstituted or bromoalkyl-~ubstituted monoole~in of the
general ~o~mula - '
R2
whereln
Rl and R4 independently o~ onq another denote hydrogen,
Cl~ to C~ alkyl, C5 to ! C7~cycloalky1, monochloro-
Cl to C5_a1ky1, monobromo-Cl- to C5~alkyl, dichloro-
Cl- to C5-a~lkyl~ dibromo-Cl- to C5-alkyl, monochloro-
C~- to C7-cyeloal~rl, monobromo-C5- to C7-cycloalkyl,
dichloro-~5- ~o C7 Gyc10alkyl or dibromo-C5- to C7-
cycloalkyl ~nd
- 6 -
, ~ . , I A . . ~ ,
,
R2 and R3 independently of one another represent
hydrogen, Cl- to C5-alkyl, monochloro-Cl- to C5-al-
kyl, monobro~o-Cl- to C5-alkyl, dichloro-Cl- to
C5-alkyl and dibromo-Cl- to C5-alkyl, it being pos-
sible ~or the radicals
R2 and R3, together with the carbon atoms of the C=C
double bond, to form a ring with up to 12 carbon atoms,
and at least one of the radicals Rl to R4 being an
al~yl or cycloalkyl radical of the type mentioned con-
taining chlorine or bromine,
is reacted with a 301ution of a percarboxylic acid containing
3 to 4 carbon atom3 in an aromatic hydrocarbon containing 6
to 12 carbon atoms at a molar ratio of monoolefin to per-
cabo~ylic acid of 1.1 to 10 : 1 and at R temperature of ~0C
to 100C~ .
W1thin the scope of the co~pounds of the formula (I),
~xample9 0~ possible compound~ are, in particular, tho~e of
the following ~ormulae: .
R5-C~`CH-R6 (II)
wherein
.
R5 and R6 independently o~ bne another denote Cl- to
C5-alkyl, monochloro~Cl- to C5-alkyl, monobromo-Cl- -
to C5-al ~l, dichIoro~el~ tb C5-alkyl or dibromo-Cl-
to C5 alkyl, 1 . ~ .
~5 ~ ~ it being po~ible ~or theradicals R5 and R6 to be
linked to form a ring, together with the group CH=CH,
and at loa~t one of ~he radicals R5and R6 denoting
monochlorQ~ to C5-alkyl~ monobromo-Cl- to C5-alkyl,
dlchloro~Cl- to C5-alk~l or dibromo~Cl- to C5 alkyl;
..
'.
, .
.
.
4~3
~C=C ~
Rg~''' \ ~10, (III)
(CH2)n
wherein
R7 and R8 independently of one another denote hydrogen,
Cl- to C5-alkyl, monochloro-Cl- to C5-alkyl, monobro
mo~Cl- to C5-alkyl, dichloro-Cl- to C5-alkyl or
dlbromo-Cl- to C5-alkyl,
Rg and Rlo independently of one another repre~ent a
methylene, chloromethylene, bromomethylene, l,2-di-
chloroethylene or 1,2-di~romomethylene radical and
. n represent~ an integer from 1 to 6, at lea~t one of
the radicals R7 - Rlo repre~enting an alkyl, cyclo-
alkyl or alkylene radical Qf the type mentioned
containing chlorine or bromine.
In detail, halogenoal~ ubstituted ~onoolefin~ which
may be mentioned are: allyl chloride, 2-chloromethyl-propene,
3-chloro-2-chloromethyl-propene, 3-chloro-1-butene:? l-chloro-
2-butene, 1,4-dichloro-2 butene~ 3,4~dichlo~o-1-butenP, ~-chlo-
ro-l-pentene, 4-chloro-2-pentene, l chloro-2-~ente~e, 1,4-di-
chloro-2-pente~e, 3,4-dichloro-1-pentene, 1,2-dichloro 3-pen- -
tene, ~-chloro~1-cyclopéntene, 1,4-dich10ro-2-cyclopentene,
3-chloro-1-hsx~né, 1-chloro-2-hexene, 1~4-dichloro-2-hexene,
3,4-dichloro-1-ho~ene, 2~chloro-3-hexene, 2,5-dichloro~3-hex-
ene, 3-chloro-1-cyclohexene, 1,4-dlchloro-2-cyclohexene,
l-chloro-2 h~ptone, 3-chloro-1-heptene, 3,4-dichloro-1-heptene,
1,4-diohloro-2-heptene~ 2-chloro-3-heptene, 2,5-dichloro-3-
heptene, 3-ohloro~l-cycloheptene, 1,4-dichloro-2-cycloheptene,
l-chloro-2-octene, 3-chloro-1-octene, 1,4-dichloro-2-octene,
8 -
2,5-dichloro-3-octene, 2-chloro-3-octeneS 3-chloro-4-octene)
3,6_dlchloro-4-octene, 3-chloro-1-cyclooctene, 1,4-dichloro-
2-cyclooctene, l-(l-chloro-cyclohexyl)-ethene, 1-chloro-2-
nonene, 3-chloro-1-nonene, 1,4-dichloro-2-nonene, 2-chloro-3-
nonene, 2,5-dichloro-3-nonene, 3-chloro-4-nonene, 6-chloro-
4-nonene, 3,6-dichloro-4~nonene, 1-chloro-3-decene, 3-chloro-
l-decene, 4-chloro-2-decene, 194-dichloro-2~decene, 2-chloro-
3-decene, 2,5-dichloro-3-decene, 5-chloro-3-decene, 6-chloro-
4-decene, 3,6-dichloro-4-decene, 4-chloro-5-decene, 4,7-di-
chloro-5-decene, 1-chloro-3-undecene, 3-chloro-1-undecene,
1,4-dichloro-2-undecene~ 2-chloro-3-undecene, 4-chloro-2-unde-
cene, 2,5;dichloro-3-undecene, 5-chloro-3-undecene~ 6-chloro-
4-undecene, 4-chloro-5-undecene, 4,7~dichloro-5-undecene,
5-chloro~6-undecene, 5,8-dichloro-6-undecene, 1-chloro-3-dode-
cene, 3-chloro-1-dodecene, 1,4-dichloro-2-dodecene, 2-chloro-
3-dodecene, 4-chloro-2-dodec;ene, 2,5-dichloro-3-dodecene,
5-chloro-3-dodecene, 6-chloro-4-dodecene, 4-chloro-5-dodecene,
4,7-d$chloro-5-dodec;ene9 5-chloro-6-dodecene, 5,8-dichloro-
6-dodecene, 5,7-dichloro 6-dod:ecene and 7-chloro-5-dodecene;
allyl bromid~, 2-bromometh~l-propene, 3-bromo-2-bromomethyl-
propene, 3~bromo-1-butene, 1-bromo-2-butene, 1,4-dibromo-
2-butene, 314-dibromo-l-butene, 3-bromo-1-pentene, 4-bromo-
2-pentene, 1-bromo-2-pentene, 1,4-dlbromo-2-pentene, 3,4-di-
bromo-l-p~ntene, 1,2-dibromo-3-pentene, 3-bromo-1-cyclopentene,
1,4-dibromo-~-cyclopentene, 3-bromo-1-hexene, 1-bromo-2-hexene~ -
1,4-dibromo-2-hexene, 3,4-dibromo-1-hexene, 2-bromo-3-hexene,
2,5-dibromo-3-hexene, 3-bromo-1-cyclohexene, 19 4-dibromo-2-
cyclohexene, l-bromo-2-heptene, 3-bromo-1-heptene, 3,4-dibromo-
l-hept~ne, 1,4-dibromo-2-heptene, 2 bromo-3-heptene, ~,5~di-
bromo-3-heptene, 3-bromo-1-cycloheptene, 1,4-dibromo-2-cyclo-
heptene, l-bromo-2-octene, 3-bromo-1-octene, 1,4-dibromo-
_ g _
..
2-octene, 2,5-dibromo-3-octene, 2-bromo-3-octene, 3-bromo-
4-octene, 3,6-dibromo-4-octene, 3-bromo-l-cyclooctene, 1,4-
dibromo-2-cyclooctene, l-(l-bromo-cyclohexyl)-ethene, l-bro-
mo-2-nonene, 3-bromo~l-nonene, 1,4-dibromo-2-nonene, 2-bromo-
3-nonene, 2,5-dibromo-3-nonene, 3-bromo-4-nonene, 6-bromo-
4-nonene, 3,6-dibromo-4-nonene, l-bromo-3-decene, 3-bromo-
l-decene, 4-bromo-2-decene, 1,4-dibromo-2-decene, 2,bromo-
3-decene, 295-dibromo-3-decene, 5-bromo-3 decene, 6-bromo-
4-decene, 3,6 dibromo-4-decene, 4-bromo-5-decene, 4, 7-dibromo-
5-decene, l-bromo-3-undecene, 3-bromo-l-undecene, 1,4-dibromo-
2-undecene, 2-bromo-3-undecene, 4-bromo-2-undecene, 2,5-di-
bromo-3-undecene, 5-bromo-3-lmdecene, 6-bromo-4-undecene~
4-bromo-5-undecene, 4,7-dibromo-5-undecene, 5-bromo-6-undecene,
5,8-dibromo-6-undecene, 1-bromo-3-dodecene, 3-bromo-1-dodecene,
1,4-dibromo-2-dodecene, 2-bromo-3-dodecene, 4-bromo-2-dodecene,
2,5-dibromo-3-dodecene, 5-bromo-3-dodecene, 6-bromo-4-dodecene,
4-bromo-5-dodecene, 4,7-dibromo-5-dodecene9 5-bromo-6-dodecene,
5,8-dibromo-6-dodecene, 5,7-dibromo-5-dodecene and 7-bromo-
5 dodecene.
Chloroalkyl-sub~tituted or bromoalkyl-Yub~tituted
monoole~in~ which are particularly suitable ~or ~e~ction with
percarboxylic acids by the process according to the invention
~re those o~ ~he ~ormula
Rll-CH=CH-Rl2 (IV)
wherein
Rll and R12 independently o~ one another denote hydrogen,
~ to C ~ lkyl,mono~oro-~- to C5-alkyl, monobromo-~-to C5-
al~yl,dlchloro ~- to C5-alkyl or dibromo-Cl- to C5-alkyl,
at least one o~ the radicals Rll and Rl2 representing
monochloro~Cl- to C5-alkyl, monobromo-Cl- ~o C5-alkyl,
d~chloro-Cl~ to C5-alkyl or dibromo-Cl- to C5-alkyl.
- 10 -
,
.
~ Q ~ 8
In detail, examples which may be mentioned are:
allyl chloride, 2-chloromethyl-propene, 3-chloro-2-chloro-
methyl-propene, 3;chloro-1-butene, 1-chloro-2-butene, 1,4-di-
chloro-2-butene, 3,4-dichloro-1-butene, 3-chloro-1-pentene,
4-chloro-2-pentene, 1-chloro-2-pentene, 1,4-dlchloro-2-pen-
tene, 3,4-dichloro-1-pentene, 1,2-dichloro-3-pentene~ 3-chloro-
l-hexene, l-chloro-2~hexene, 1,4-dichloro-2-hexene, 3,4-di-
chloro-l-hexene, 2-chloro-2-hexene, 2,5-dichloro-3-hexene,
3-chloro-1-cyclohexene and 1,4-dichloro-2 cyclohexene; allyl
bromide, 2-bromomethyl-propene, 3-bromo-2-bromomethyl-propene,
3-bromo-1-butene, 1-bromo-2-butene, 1,4-dibromo-2-butene,
3,4-dibromo-1-butene, 3 bromo-l-pentene, 4-bromo-2-pentene,
1,4-dibromo-2-pentene J 3,4-dibromo-1-pentene, 1,2-dibromo-
3-pentene, 3-bromo-1-hexene, 1-bromo-2~hexene, 1,4-dibromo-
2-hexene, 3,4-dibro-1-hexene, 2-bromo-~-hexene~ 2,5-dibromo-
3-hexene, 3-bromo-1-cyclohexene and 1,4-dibromo-2-cyclohexene.
1,4-Dichloro-2-butene, 1,4-dibromo-2-butene and
3,4-dichloro-l~butene are very particularly suitable for reac-
tion wlth peroarbo~ylic acids by the process according to the
~o invention.
Th~ most diverse aromatic hydrocarbons with 6 to 12
.
carbon atom~, which can also be substituted, can be used as
solYent~. Po3~1ble examples arebenzene, nitrobenzene, tolu-
ene, xylene, ethylbenzene, diethylbenzene, cumene, diisopro-
pylhenzene and chlorobenzene.
Aromatic hydrocarbons with 6 to 8 carbon atoms, such as
benzene, ni~robenzene~ chlorobenzene, toluene, xylene and ethyl-
benzene, are particul rly ~uitable.
P~eferred solv~nts are benzene and toluene. A par-
ticularly pre~erred solvent is benzene. Mixtures of
different aromatic hydrocarbons can also be used.
, .. . .
Peracids which can be used according to the invention
are perpropionic acid, perbutyric acid and perisobutyric acid.
Perpropionic acid and perisobutyric acid are preferably used.
Perpropionic acid is particularly preferred. The prepara-
tion of the mineral acid-free peracids in one of the organic
solvents mentioned can be carried out, for example, by the pro-
cess descrlbed in DOS (German Published Specification)
2,262,970.
In general, when carrying out the process according to
the invention in practice, it is carried out in a temperature
range ~rom 30-100C. It is pre~erably carried out at
60~80C and particularly preferably at 65-75C. In
special cases, the process can also be carried out below or
above the temperatures indicated.
Besides the procedure under isothermal conditions,
that is to say maintaining~a uniform temperature in the entire
reaction mixture, it is also possible to carry out the reac-
tion with the setting up of a so-called temperature gradient,
which in general increases as the reaction progresses~ How-
ever, lt 1s also pos~ible to carry out the reaction in a
manner ~uch that a decreasing temperature gradient is set up
as~the~reaction progre~es.
According to the invention, the molar ratio o~ olefin
to p~racid is 1.1 : 1 to 10 : 1. A molar ratio of 1.25 : 1
to 5 : 1 is pre~erably used. It is very particularly advan-
tageous to use a molar ratio of 105 to 3.0 mols of olefin per
mol o~ peracidO
The process according to the invention can be carried
out under the most d.~er~e pressures~ In general9 it is
carried out under normal pressure; however, the process can
al80 be carried out under reduced pressure or excess pressure.
12 -
.
., . ,.,~ , .: . . .
0~8
In ganeral, the water content of the percarboxylic
acid used for the epoxidation should be as low as possible,
Low amounts of water of up to 5% by weight are generally not
troublesome. A percaboxyllc acid with a water content of
up to 2% by weight, for ex~mple, is suitable. A percar-
boxylic acid solution w~lich contains less than 1% by weight
of water is pre~erably uqed. A water content of less than
0.1~ by weight is particularly preferred.
In general, the h~drogen peroxide content of the per-
carbo~ylic acid used should be as low as possible. It can
be up to Z~ by weigh~. The reaction is advantageou~ly car-
ried out with a hydrogen peroxide content of less than 1% by
weight. It is particularly advantageous to car~y out the
reaction with a percarboxyl~c acid solution which has a hydro-
gen peroxide content below 0.3%.
The mineral acid content of the percarboxylic acid
solutlon used ~or the reaction should be as low as possible.
It is advantageou~ to carry out the reaction with a percar-
boxylic acid ~olution which ha~ a mineral acid content below
50 ppm. A miner~l acid content o~ less than 10 ppm is par-
ticularlr ad~antageous.
Th~ reaction can be carried out discontinuously or con-
tinuou~ly in the customary devices for reactions of this type,
such as atirred kettles, boiling reactors, tube reactors, loop
reactors or circulatory reactors~
~la~, st~inless steels or enamelled material can be
us~d a~mat@~ia~ o~ construction for carrying out theprocesses.
Heavy metal ions in the reaction mixture catalyse the
decompositlon o~ the percarboxylic acid. Substances which
lnactiv~te the heavy metal ions by means of complex formation
~re therefQ~e gen~rally added to the percarboxylic acid
- 13 -
solution~ Known substances of this type are gluoonic acid,
ethylenediaminetetraacetic acid9 sodium silicate, sodium
pyrophosphate, sodium hexametaphosphate, disodium dimethyl
pyrophosphate or Na2(2-ethYl-heXYl)s(P30lo)2 (DAS (German
Published Specification) 1,056,596, column 4, line 60 et seq).
The halogenoalkyl-~ubstituted olefin can be introduced
in various ways into the device used for the reaction. It
can be put into the reactor together with the percarboxylic
acid solution, or the two components are fed in separately
from one another. Furthermore, it is possible to intro-
duce the olefin and the percarboxylic acid solution into the
reactor unit at different points. If several reactors con-
nected in a cascade are used, it can be appropriate to
introduce all the olefin into the first reactor. However,
it iq also possible to distribute the olefin among the vari-
ous reactors.
The heat of reaction is removed by internal or exter-
nal cooler~. In order to remo~e the heat of reaction, it
is also po~sible to carry out the reaction under reflux (boil-
in~ reactQrs).
The reaction is appropriately carried out with as com-
plete a~ pos~ible converslon of the percarboxylic acid. In
gcneral, more than 95 mol % o~ the percarboxylic acid are reac-
ted. It is appropriate to react more than 98 mol % of the
peracid.
When the reaction between the halogenoalkyl-
sub~tituted ole~in and the peracid is carried out according to
the invsntion, it i8 possible to achieve oxirane yields of 90%
of theory and more, relative to percarboxylic acid employed.
Th~ reaction mixture is wor~ed up in a manner which is
in itsel~ kno~n, ~or example by distillation. It is
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- ~2~
particularly advantageous to extract the reaction mixture
with water, before working up by dlstillation, in order to
separate off the carboxylic acid, corresponding to the per-
carboxylic acid, which is formed during the reaction. The
extraction can be carried out in the customary extractors,
such as mixertseparators,perforated tray extractors, pulsating
per~orated tray columns, rotatlng disc extractors or extrac-
tion centrifuges.
In a preferred manner of carrying out the process, an
approximately 20% strength by weight solution of perpropionic
acid in benzene is added to three times the molar amount of
halogenoalkyl-substituted ole~ln~ which is thermostatically
controlled at 70C, whilst stirring. The perpropionic acid
solution contains less than 10 ppm of mineral acid; it has a
water content which is below 0.1% and has a hydrogen peroxide
content of less than 0.3%. Before the reaction, about
0 05~ by weight of Na5(2-ethylhexyl)5(P3010)2 was
perpropionic acid in order -to complex heavy metal ions. The
proKress and the end of the reaction are monitored by removing
samp` e9 from the reaction solution at intervals of time and
determining tritrimetrically the content of percarboxylic acid
still present. A~ter the reaction has ended, the reaction
mixture is cooled and washed three times with the same amount
by weight o~ water in order to remove the propionic acid.
The propionic acid-free reaction mixture is then fractionated.
The example~ which ~ollow illu~trate the invention,
Unle~s indicated otherwise, all the percentage data represent
per cent by weight.
Preparation of epichlorohydrin from allyl chloride and per-
propionic acid.
~ - 15 -
,
~%~
45 g o~ 20% strength perpropionic acid in benzene
(0.1 mol) were initially introduced into a 200 ml three-
necked double-walled ~lask with a magnetic stirrer, internal
thermometer, dropping funnel and re~lux condenser and were
thermostatically controlled at 70C. Thereafter, 22.96 g
(0.3 mol) of allyl chloride are added dropwise such that the
temperature could be kep-t at 70C. After stirring under
reflux ~or a further 6 hours, tritrimetric analysis gave a
perpropionic acid conversion of 98.5%. Analysis of the
reaction mixture by gas chromatography showed that epichloro-
hydrin was formed with a selectivity of 97.5%, relative to
perpropionic acid employed. After cooling, the reaction
mlxture was washed several times with water in order to
remove the propionic acid and was then fractionated. 8.73
g of epichlorohydrin resulted,
xample 2
Preparation o~ 2-(1,2~dichloroethyl-)oxirane from 3,4-di-
chloro-l-buten~ and perpropionic acid.
62.9~ g (0.147 mol~ of perpropionic acid, as a 21%
~treng~h svlution in benzene, were added dropwise to 55.87 g
(0.447 molj of 3,4-dichloro-1-butene at 70C, whilst stirring.
After the dropwise addition, the mixture was stirred at this
temperature ~or a ~urther 6 hours, and tritrimetric analysis
then ~howed a perpropionic acid conversion o~ 97%. Ths
reaction solut{on was cooled to room temperature and analysed
by gas chromatography. As the analysis showed, 2-(1,2-di-
chloroethyl-)-oxirane was ~ormed with a selectivity of 94.Z%,
relat~ve to perpropionic acid employed.
The reaction mi~ture was washed several times with
water in order to remo~e the propionic acid, benzene was dis-
till~d o~ and the re~ction product was then ~ractionated in
., -
a 40 cm packed column, packed with 4 mm glass Raschig ring~.
18.9 g of 2-(1,2-dichloroethyl-)-oxirane were isolated with a
purity of 99.4%.
Ex~mple ~
Preparation o~ 2,3-bis-(chloro~ethyl)-oxirane from 1,4-di-
chloro-2-butene and perpropionic acid.
63.97 g (0.147 mol) o~ perpropionic acid, as a 20.68%
strength solution in benzene, were added dropwise to 55.2 g
(0.4416 mol) of 1,4-dichloro-2-butene at 70C and the mixture
was then further stirred at this temperature. A~ter a
reaction time of 4 hours, the peracid conversion was 96%, and
a~ter 6 hours it was over 99%. 2,3 Bis(chloromethyl)-oxi-
rane was formed with a selectivity of 96.5%, relative to per-
propionic acid employed. After removing the propionic acid
by extracting the reaction mixture by shaking several time~
with water and subsequently ssparating o~f -the benzene by dis-
tillation, and after fractionation of the reaction product
over a ~0 cm packed column, filled with 4 mm glass Raschig
rings, 19.6 g of 2,3-bis-(chloromethyl)-oxirane were obtained
with a purity of 99.g%~
~cntinuou~ preparation o~ 2,3-bis-(chloromethyl)-oxirane from
1,4-diohloro-2-butene and perpropionic acid.
A solution of perpropionic acid in benzene, to which a
~tabili~er o~ the type9 which is commercially available, con-
sisting o~ sodium salts of polyphosphoric acids partially
esterified with loffg-chain alcohols has been added, was reac-
ted with 1,4~dichloro-2 butene in a reaction system in the ~orm
of a t~ ee-stage ca~cade o~ stirred kettles. Each o~ the
throe ~stirred ~ettles had a volume of 10 1. The kettles
were heated via heating coil~ located in the kettle. All
Le A 17 776 - 17 -
4~3
three kettles were the~no tatically controlled at 70C.
2,137.5 g (4.75 mols) of perpropionic acid, as a 20%
strength solution in benzene, and 1,781.25 g (14.25 molsj of
~ dichloro-2-butene per hour were fed into -this reaction
system, which corresponded to an average residence time of
about 8 hours. Under these reaction conditions, the per-
propionic acid was converted ~o the exten~ o~ 96.~%. The
selectivity of the 2,~-bis-(chloromethyl)-oxirane formed was
96%, relative to perpropionic acid amployed.
The reaction mixture obtained after the third reactor
had the following average composition: 35.6% of benzene,
30.8% of 1,4-dichloro-2-butene, 16.24~ of 2,3-bis-(chloro-
methyl)-oxirane and 17% of propionic acid. This mixture
was extracted in a pulsating per~orated tray column with twice
the amount of water in order to separate off the propionic
acid. Therea~ter, the residual content of propionic acid
was 0.04%. The reaction mixture obtained after this opera-
tion wa~ fractionated in a distillation line. Benzene was
di~tilled in a fir~t column in an amount o~ 1,395 g per hour.
The bot~om product o~ this column, which essentially consisted
of star~ing materlal and oxirane~ waq ~ractionated in a second
column under reduced pressure. 1,206.5 g o~ 1,4-dichloro-
2-butene per hour were obtained a~ the head product. The
bottom pr~duct o~ thi~ column waq freed from high-boiling
constituents i~ a third column under reduced pressure.
629.5 g of 2,3-bis-(chloromet~yl) oxirane per hour were
obtained as the head product with a purity of over 99.~.
Thi3 correspond~ to a yleld o~ 94%~ relative to the perpro-
pio~ic acid employed in the reastion ystem~
.. ,~.
L~ a~ 18 -
:. ~
Epoxidation of 1,4-dibromo-2~butene with perpropionic acid.
a) Bromination of butadiene
171.4 g (3.17 mols) of butadiene were dissolved in
400 ml of n-hexane. 314 g (1.964 mols) of bromine were
added dropwise at -20C, whilst stirring. After the end
of the dropwise addition, the mixture was stirred at this
temperature ~or a further 2 hour~. It was then allowed to
warm to room temperature and the solvent was removed in vacuo.
380.4 g of crude dibromobutene resulted, the ratio of 1,4-di-
bromo-2-butene to 3,4-dibromo-1-butene being about 2 : 1.
The 1,4-dibromo-2-butene was isolated by distillation.
b) Reactlon of 1,4~dibromo-2-butene with perpropionic acid
45 g of 20% strength perpropionic acid in benzene
(Ool mol) were added dropwise to 64.2 g (0.3 mol) of 1,4-di-
bromo-2-butene at 70C, whilst stirring, and the mixture was
stirred at this temperature for a further 4 hours. After
this time, the peracld conversion was 95%. Analysis by ga3
chromatography ~howed that the epoxide was ~ormed with a selec-
tivity o~ 92.6%, relative to perpropionic acid employed.
After cooling, the reaction mixture was washed several times
with water in order to remove the propionic acid and the reac-
tion product was fractionated. 20~7 g o~ epoxide were
obtained.
~La~ - 19 -
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