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Патент USA US2405702

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Patented Aug. 13, 1946
2,405,702
UNITED STATES
ATENT OFFICE.
PROCESS FOR PREPARING PYRANTHRONE
Henry R. Lee,w Pitman, andv Joseph Deinet and
Hans B. Gottlieb, Glassboro, N. J., assignors to
E. I. duPont de Nemours & Company, Wilming
ton, DeL, a ‘corporation of Delaware
- No‘ Drawing. Application May 23, 1944,
Serial No. 536,986
_1. Claim. (01. zero-ease)‘
1
25
This invention relates to an improvement in
the. process for preparing pyranthrone, and more
particularly to a process whereby crude 2,2’-di
methyl-l,l’-dianthraquinonyl, which has been
In‘ this‘ fusion, the dimethyldianthraquinonyl is
prepared from a crude l-halogen-Z-methylan
thraquinone, is converted to the 2'-phenoX'y-3‘
methylanthraquinone or isomeric products, which
phenoxy derivatives are'readily removed from the
thraquinone, is condenseddirectly to pyranthrone
without. puri?cation of they intermediates.
The 1-halogen-Z-methylanthraquinone, which
is prepared by the halogenation of Z-methylan
ring-closed to pyranthrone while the isomeric
halogenmethylanthraquinone, which may be con
sidered, in the main, the 2-ha1ogen-3-methylan
pyranthrone by simple dilution of the reaction
mass with ethyl alcohol or by extraction of the
thraquinone as such oras it is ring-closed from 10 pyranthrone, after ?ltration, with other organic
the methylorthobenzoyl benzoic acid,.is always
solvents. As an alternative method of separating
contaminated with large amounts of isomeric
out the relatively pure pyranthrone, the reaction
methyl-halogenanthraquinone compounds, . and,
mass may be ?ltered after extraction with water
and dissolved in concentrated sulfuric acid at
more particularly, the 2-halogen-3~methylan
thraquinone. In the preparation of the 2,2'-di
room temperature, after which. it. is drowned in
water, ?ltered, and. washed acid-free. This lat
ter process appears: to sulfonate the phenoxy de
anthraquinone prior to condensation, and, after
rivative, rendering. it water-soluble, whereby it is
condensation to the dianthraquinonyl, a further
readily removed from the pyranthrone by ?ltra
puri?cation of the \dianthraquinonyl was re
tion
and washing with water.
20
quired, for the methods heretofore employed for
The following examples are given to illustrate
effecting ring-closure of the 2,2’—dimethyl-1,1'
the invention. The parts used: are by weight.
dianthraquinonyl made it advisable to employ
Erample 1
very pure dianthraquinonyl. Even after these.
puri?cations, the overall yields of pyranthrone 25 _ One part’ ofwell powdered crude-2,2"-dimethyl
1,I’-dianthraquinonyl_, containing 25% of 3
were, not satisfactory, so that it has generally
bromo-2-methylanthraquinone as an admixture,’
been. found more, advantageous to produce the
pyranthrone starting. with the l-nitro-Z-methyl
was gradually added‘ with agitation to a melt- of
1.8 parts of caustic potash» in 4.7 parts of phenol
anthraquinone which is converted ?rst. to the ‘1
amino-2-anthraquinone._ then,v after 'diazotiza
at 115“ C; during. the courseof 15 minutes. The
methyl-1,1'-dianthraquinonyl, it has therefore
been necessary to purify the 1-chloro-2-methyl
tion,._ to the dianthraquinonyl compound.
.
It: isan object of the present invention to pro
vide a process for preparing pyranthrone directly
from the crude .1-halogen-2:-methylanithraqui
none, which process will give the pyranthrone di
rectly in good yields without requiring puri?ca
tion of the dye intermediate employed-or pro
duced in the reaction. It is a further object of
the invention to provide a process for the prepa
temperature of. the agitated masswas then. raised,
kept ?rst» at, 125° C. for- 0:5 hour and later at
140° to 145°" C. for 3.5 hours. The mass Was
drowned into 10 parts of, water» and aerated- at
90“ C. for the oxidation- of the: leuco pyranthrone
for 3 hours. The product was collected, extracted.
with'lO parts of 3%. caustic soda, washed free
from phenol with. dilute caustic, then freed from
alkali. with hotwater and dried. The resulting
ration of pyranthrone starting from the crude
powdered mixture Was extracted with 5 parts of
dye intermediates by av process which does not 40 nitrobenzene at 130»u C. for 0.5 hour, was filtered
involve‘ further puri?cation steps, and which pro
duces the pyranthrone'of a quality equal to the
at. 100i to’ 11b’?I C., washed. with ethanol to re
move the nitrobenzene, and dried. All of the 3
phenoxy-Z-methylanthraquinone had been re
commercial pyranthrone of today’s standards.
We have found that pyranthrone of standard 45 moved by nitrobenzene. Pure pyranthrone was
quality can be obtained directly from the crude
obtained in 95% yield, based on the 2,2'-dimeth
y1—1,1'-dianthraquinonyl contained in the orig
l-halogen-Z-methylanthraquinone, where the
inal crude quinonyl.
crude 2,2’-dimethyl-1,1’-dianthraquinonyl con
taining even as high as 50% of uncondensed iso
Example 2
meric halogenmethylanthraquinones is used 50
One part of a Well powdered crude 2,2'-di
with phenol and alkali metal hydroxide. With
methyl-1,1’-dianthraquinonyl, containing 20% of
crude 2,2'-dimethyl-1,1’-dianthraquinonyl con
3-bromo-2-methylanthraquinone as chief admix
taining up to 25% of 3-halogeno-2-methylan
thraquinone as impurity, our new fusion is more
ture, was charged at 125° C. into an agitated melt
economical than standard commercial methods. 65 of 2 parts of caustic potash and 4 parts of phenol.
2,405,702
3
4
The temperature of the fusion was raised and the
mixture stirred for 4 hours at 145° to 150° C.
After cooling to 110° 0., 4 parts of ethanol were
added with agitation and the whole ?ltered at 70°
C. The ?lter cake was washed with 8 parts of
ethanol and ?nally with hot water until free from
alkali and bromide. The yield of pure pyran
throne amounted to 96%-99%, based on 2,2’-di
methyl-1,1’-dianthraquinonyl contained in the
tion, and that various modi?cations of the same
are possible without departing from the spirit of
this invention. The ratio of the phenol to the
crude dimethyldianthraquinonyl and the ratio of
ranthrone was isolated in good yield, based on
same.
the caustic to the phenol, or the duration of the
fusion, may be varied within reasonable limits.
The temperatures?ikewise, may be varied, it be
ing understood, of course, that with too low a tem
perature the reaction becomes too slow to be
original crude quinonyl.
10 practical. Temperatures greatly in excess of those
3-phenoxy-2-methyl-anthraduinone is readily
given in the examples, however, are not required.
The phenoxymethylanthraquinone impurities
isolated from the phenolic-alcoholic mother
liquor.
'
produced during the fusion, more particularly the
Example 3
3-phenoxy-2-methylanthraquinone, may be re
moved
from the pyranthrone by using solvents
16
The starting material used in this instance was
other than alcohol or nitrobenzene. Orthodi
a crude quinonyl containing 40% of 3-chloro-2
chlorobenzene, or any other solvent in which this
methylanthraquinone as the principal admixture.
material is preferentially soluble, may of course
This product was subjected to phenol-caustic
be employed.
potash fusion under the conditions described in
It will be obvious that the phenol may be sub
Example _2 for the crude quinonyl containing 20
stituted by other hydroxybenzenes, such as, for
bromo product. The fusion was worked up in an
instance, cresols or commercial mixtures of the
identical manner with Example 2 and pure py
2,2'-dimethyl-1,l'-dianthraquinonyl contained in
the original crude quinonyl.
'
This process has a very important technical ad
25 vantage over the previously known processes in
that the pyranthrone can be obtained directly and
Example 4
without recrystallization from impure 2,2'-di
methyl-1,1’-dianthraquinonyl, which, in turn,
' One part of a well powdered crude 2,2'-di-
was obtained from the very impure l-halogen-2
of 3-bromo-2-methylanthraquinone, was charged 30 methylanthraquinone without isolation or puri?
cation of the intermediates. If such impure di
at 125° G‘. into an agitated melt of '2 parts of
methyldianthraquinonyl is ring-closed directly by
caustic soda and 4 parts of phenol. The temper
the usual alcoholic caustic fusion methods, the
ature of the agitated fusion was brought to 150°
resulting pyranthrone gives dull and unsatisfac
, C.'and kept at 150° to 152° C. for 4 hours.
methyl-1,1’-dianthraquinonyl, containing 20%
The melt was worked up as described in detail‘ 35 tory dyeings, and expensive and time-consuming
recrystallization of such product is required to
give a dye of satisfactory purity. On the other
in Example 2. Pure pyranthrone was obtained in
good yield, based on 2,2'-dimethyl-l,l’-dianthra
quinonyl contained in the original crude quinonyl;
hand, if the pyranthrone of satisfactory purity
were to be obtained starting with impure l-halo
Ewmple 5 ' ‘
gen-2-methylanthraquinone, the puri?cation of
the resulting dimethyldianthraquinonyl requires
large crystallization losses and materially reduces
One part of a well powdered’ crude 2,2'-di
methyl+l,1’-dianthraquinonyl, containing 5% ‘of
-3—bromo-2-methylanthraquinone, was charged
at 125° C. into an agitated mass of 2 parts of
the yield of the resulting pyranthrone, based on
the original starting material. By the present
caustic potash and 4 parts of phenol. Thefusion
- V invention, the pyranthrone is formed directly and
was heated to 145° to 150° C. for 4 hours, allowed
need only be washed from by-products, using
suitable solvents, which simple operation involves
to cool, and drowned into 15 parts of water. The
mass was ?ltered, the cake extracted with'dilute'
caustic, washed free from phenol and alkali, and
no substantial loss of the 'pyranthrone itself.
We claim:
dried. This crude pyranthrone was puri?ed and "3
converted into dye paste in one step. The ?nely
powdered crude was dissolved in 8 to 10 parts of
concentrated sulfuric'acid and agitated at room‘
temperature-for 2 hours. In this treatment the
admixed 3éphenoxy-Z-methylanthraquinone was -'
completely sulfonated and remained dissolved,
when the sulfuric acid solution was drowned into
resulting pyranthrone was of excellent shade and
>
7
It is of course understood that the above ex
amples are given merely to illustrate the inven
pyranthrone from an impure 2,2'-dimethyl-1,1'
dianthraquinonyl containing substantial amounts
of 2-ha1ogen-3-methylanthraquinones, which
comprises fusing the crude 2,2'-dimethyl-1,l'-di
anthraquinonyl with a phenol and an alkali metal
hydroxide, diluting the fusion mass with ethyl
alcohol, ?ltering o? the pyranthrone, and wash
ing the resulting pyranthrone cake with alcohol
water for the preparation of the dye paste. The
strength.
.
The process for preparing a relatively pure
and with water.
60
.
>
’
HENRY R. LEE.
JOSEPH DEINET.
HANS B. GOTI'LIEB.
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