Note: Descriptions are shown in the official language in which they were submitted.
~` - ~ ~
case 1
ILIL¢~9
PROCESS FOR REMOVING IMPURITIES FROM
POLYALKYLENEOXY COLORI NG AGENTS
The present invention relates to a process for purifyiny
~olymeric coloring agents. More particularly the present inventio
relates to a process for separating poly~eric alkyleneoxy coloring
agents from impurities normally ~resent in a crude reaction pro-
duct by means of ~he cloud point phenomenon.
Polymeric, alkyleneoxy, chromophoric group containing com-
pounds have been known for manv years as disclosed in U. S.
Patent Number 3,157,633 to Ruhn
Typically such compounds may be water soluble and they have
accordingly ~een used extensively, as disclosed by Kuhn, as ugi-
tive tints in the textile industry because they may be easily re-
moved from textile fibers by scouring with aqueous solutions.
Recently, it has been discovered that certain polyalkyleneo
compounds may advantageously be employed as colorina agents in
resin svstems where the coloring agent may react with the resin
and actually be bound to the resin by covalent bonding. Such
coloring agents and methods for colorin~ resins are disclosed in
U.S. Patent Number 4,284,72g filed March 31, 1980 to
John P. Cross and ~.eorge H. Britton, JrO Un-
fortunately, however, the methods known in the art for preparing
~olyalkyleneoxy compounds, as disclosed for instance in the Kuhn
patent, have typically resulted in a reaction product being pro-
vided in the form of an aqueous solution containing substantial
amounts of water soluble impurities, e.g., inorganic salts, which
may be detrimental in end use applications of the ty~e disclosed
in the Cross et al. application, ~hat is where the~ are emploved
as coloring agents. It, th~refore, would be hiqhly desirable to
I
~ 39~
remove those impurities from the compositions before they are
actually employed for their intended end use applications. Thus,
the present invention is directed to a method whereby such im~
purities may be removed from pol~meric, polyalkyleneox~ coloring
agents.
Accordlng to the present invention a process is provided
for removing impurities from a polvalkyleneox~ coloring agent,
which comprises heating a crude reaction product containing said
polyalkyleneoxy coloring agent and impurities to a temperature at
which the crude reac-tion product separates in-to two liquid phases,
one phase containing said coloring agent in relatively pure form
and the other phase containing said impurities; and separating the
phase containing said coloring agent from the phase containing
said impurities.
~he polyalkyleneoxy coloring agents oE the present inven-
tion may be provided in the liquid or solid phase at ambient con-
ditions of temperature and pressure. Preferred compounds accordinl J
to the invention ~.ay be characterized by the general formula:
R-(polymeric constituent-x)n
where R is an organic dyestuff radical, the polymeric constituent
is selected from polyalkylene oxides and coPolymers of polyalky-
Lene oxides in which the alkylene moiety of the polymeric con-
stituent contains 2 or more carbon atoms, and such polvmeric con-
stituent has a molecular weight oE from about 100 to about 10,000;
n is an integer of from 1 to about 6; and x is selected from -OH,
-NH2 and -SH. Preferred amongst the compounds of the abo~e formul
` are those wherein R is attached by an amino nitrogen to thepolymeric constituent. Compounds contemplated within this class
are those wherein R is a nitroso, nitro, azo, including monazo,
~L~g99~ ~
diazo and triazo, diphenylmethane, triarylmethane, zanthene,
acridene, methine, thiazole, indamine, azine, oxazine, or
anthraquinone dyestuff radical~
A preferred method for preparing the polyalkyleneoxy
coloring agents which may be purified according to the present
invention is to first convert a colorless intermediate compound
into the corresponding polyethyleneoxv compound and then ernploy
the resulting compound -to produce compounds having chromophoric
groups in the molecule. For instance, in the case of azo dye-
stuffs, this may be accomplished bv reaeting a primary or
secondary aromatic amine, preferably the former with ethylene-
oxide, propyleneoxide or mixtures thereof aecording to proeedures
well known in the art and then coupling the resulting eompound
with a diazonium salt of an aromatic amine.
lS Some of the other classes oE dyestuffs such as the anthra-
~uinones having ehlorine, bromine or iodine attached to the
aromatie nucleus, may be reaeted with, for instance, exeess
polyalkylene glyeol monoamine to produee the eorresponding
seeondary amine.
~0 The polyethyleneoxy group can be introduced in other wat~s
to produce the polyalkyleneoxty coloring agen-ts. For examPle,
anthraquinone-2-carboxylic acid can be reacted with a molar excess
of a polyethylene glycol ~aving a moleeular weight above about
1350, e.g., in the ~resence o~ p-toluene-sulfonic acid in a suit-
able solvent, e.g., dioxane or nitro-benzene, to ,~roduee the
eorresponding polvethvlene glyeol monoester of anthra~luinone-2-
earboxylie acid. The reaction can also be conducted on other
anthraauinone carboxvlic acids eontaining one or more additional
~ 9~l~
chromophoric or other non-interfering groups in the molecule. An
aromatic amine, e.g., aniline or nuclear suhstituted aniline, can
be reac-ted with a ~olyethylene glycol as described above under
pressure at a -temperature of about 220C to 230C, preferably in
the presence of iodine or a copper or sodium hal.ide as a ca-talyst.
The resulting amine, e.g., the polyethylene glycol substituted
aniline, can then be coupled with the usual diazonium salts, e.g.,
H acid, to produce a diazo polyalkyleneoxy coloring agent.
An aromatic bromo compound, e.g., 2-bromoanthraquinone, can
be reacted with polyethylene glvcol in -the presence of sodium at
150C to produce the corresponding anthra~uinone polyethylene glv-
col ether. A nitrophenol, e.g., p-nitrophenol, can be reac-ted
with polyethylene glvcol in the same manner to produce the
p-nitrophenol polyethy]ene glycol ether. I'his compound can then
be reduced by any of the me-thods well known in the art for re-
ducing aromatic nitro groups, e.g., 2inc and acetic acid, hydrogen
and catalyst, to produce the corresponding p-amino compound which
can then be dia~otized and coupled with a suitable aromatic com-
pound, e.g., "H" acid, to produce a polyalkyleneoxy coloring agent
~0 which may be purified according to the present invention.
Typically, all of the above procedures for preparing ~oly-
meric, alkyleneoxy, chromo~horic group containing compounds may
result in the compound being produced in a crude reac-tion mixture
containing substantial amounts of impurities in the form of by-
products produced during the svnthesis of the desired compound.
These materials are generally wa-ter soluble, e.g., inorganic salts,
as is the chromophoric group containing compound makiny separation
based on differiny solubilitY ~uite difficult if not impossible.
~rheir pr ence, furthermore, is undesirable ln a colorinq aqent
11~991(~
product desiqned, for instance, for incorporation into urethanes
by the formation of covalent bonds because they may interfere with
the polymerization reaction. Until the present invention, further
more, no fully satisfactory method has been available for the re-
moval of such impurities from the reaction mixture. It has now
been discovered, however, that by makiny use of a rather unus-lal
property of these compounds a simple, and effective separation of
the compounds from impurities ~resent in the crude reaction mixtur
may be accomplished. The separation is accomplished by simply
heating the crude aqueous reaction mixture at least to the cloud
point. On passing the cloud point, the crude reaction mixture
separates into two phases - one phase containing the colorant and
a second aqueous phase containing substantial amounts of impuritie
such as water solub:le sa:lts. 'l'he two phases may then be separated
by any of the means known in the art. Additional water may be
added to the colorant containing phase and the separation may be
repeated one or more times to further purify the colorant.
The following examples illustrate the invention but are not
to be construed as a limita-tion thereof. The ~arts and percentage
are all by weiyht unless otherwise specified.
PREPARATION I
__
Ethylene oxide was bubbled into warm aniline under nitroyen
until two molar e~uivalents of ethylene oxide were consumed~ Ther
was thus produced N,N-dihydroxyethylaniline, which solidified on
coolin~ to room temperature.
Similarly, meta-toluidine was treated with ethylene oxide
producinq N,N-dihydroxyethyl-m-toluidlne.
PREPI~RATION II
______ .
Five hundred forty-three grams (3 moles) oE N,N-dihydroxy-
ethylanil e and 2.S qrams pota~]um hydroxlde wer- placed in a
l~L99910
2 liter stainless steel ~ressure reator e~uinped with an agitator
gas inlet tube and vent. Af~er purgincj wi-th nitrogen, the reactor
and contents were heated at 100C under vacuum and held on temper-
ature for 0.5 hours. The vacuum was bro~en with nitrogen and the
reactor was heated to 150C. Ethylene oxide was added through the
inlet tube until eight eauivalents were consumed. ~fter ?ost
reacting for 30 minutes, the mixture was subjected to vacuum for
30 minutes, then cooled to room tem~erature. The thus produced
intermediate:
~ (CH2CH2-ot5H
~ -N
~CH2CH2 Ot5H
was an amber, freeflowing liquid.
PREPARA'rION III
The method of Preparation II was followed, using ~1,N-
dihydroxyethyl-m-toluidine and enough ethylene oxide to add eight
moles. The product was -the formula:
~ ~ ~(cFl2cH~-~tsH
(CH2CH2 O~5H
and was a liquid at room temperature.
EXAMPLE I
To a 2 liter glass reactor was charged aniline (47.9 grams,
0.52 moles), which was cooled to 0C. Hydrochloric acid (16:l
grams) was added dropwise with stirring, and the resulting mix-ture
cooled to 0C. Sodium nitrite (40.3 grams, 0.58 moles) was dis-
solved in wa-ter (80 milliliters) and added dropwise to the aniline
solution while maintaining the temperature helow 5C. ~1hen
6-
11999~0
addition was complete, the mixture was stirred for 30 minutes and
excess nitrite was confirmed by sta-cch-iodide paPer~ Sulfamic
acid was added i~n portions until excess ni-trite was consumed.
In another reactor, the intermediate of Pre~aration III
(282 grams, 0.52 moles) was charged. ~ solution of sodium acetate
(29.6 grams, 0.36 moles) in water (51 milliliters) was prepared.
The previously prepared aniline diazonium solution was added in
portions using the sodium aceta-te solution to maintain the pH of
the coupling bath at 4-5. rremperature was maintained below 10C.
'I'he mixture was DOS t-stirred for one hour after addition of dia-
zonium salt was complete.
The mixture was poured into a beaker and heated to 95C
on a steam bath. The colorant formed a layer on top of the
solution and was decanted. 'L'he thus isoLated material, a dark
liquid, was treated with an equal volume of water and heated to
35C whereupon the formation of two phases again occurred. This
time the colorant formed a layer on the bottom. The aqueous layer
was decanted and discarded. The colorant was again treated with
water and two phases formed by heating to 95C. Tlle aqueous layer
~0 was decanted and discarded.
After removing vola-tile componen~s at 85C and 2 m~Hg
vacuum to 99.4 percent nonvolatile, a yellow colorant was ob-
tained:
CH3
~ ~ 3 N /
(Cil2CH2-Ot5H
1~99~310
EXAMPLE II
In a manner similar to Example 1, aniline and the e-thoxy-
lated intermediate of Preparation II were coupled glving a yellow
colorant of the structure:
~ ~ ~ /(CH2CH2-O~5H
(CH2CH2-Ot5EI
EXAMPLE_III
In a manner similar to Example I, 2-amino-5-nitroanisole
and the intermediate o:E Preparation III were coupled givinq a red
colorant:
O - ~ W =W ~ 2 2 tS
CH3 (CH2cH2-~5H
EXAMPLE IV
Using the methods described in U. S. Patent 4,137,243, a
colorant was prepared from quinizarin and a diamlne of molecular
weight 230 derived from a polypropylene oxide. The resulting
viscous blue colorant has the structure
CH3 C1~3
H ~ ~ (CH2-C~I-Otl 6CH2CH-NH2
\., ~d
( 2 H Otl 6CH2CH NH2
~ 9~3
EXAMPLE V
_
Using standard procedures, 2-amino-6-methoxvbenzothiazole
was dia~otized with nitrosylsulfuric acid and coupled with the
intermediate of Preparation III at a pH of 2. After a procedure
similar to that of Example I, a red colorant was obtained:
CH30 S (CH2CH2-O~5H
: CH3
EXAMPLE VI
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Exam~-le of Incor~~oration into_a FLexible
PoLyester E~olvurethane Foam
,~
To a mixture of a pol~ester ~olyol of hydrox~$71 number 46
(100 grams), water (3.6 yrams), a silicone based emulsifier
(1.3 grams), stannous octoate (0.4 grams) and ter-tiarv amine
catalyst (0.3 grams) was added 0.1 gram (0.1 ph~) of the yellow
. single component li~uid reactive coloring agent of Example I.
The mixture was stirred for 30 seconds to ensure a homogeneous
mixture. Toluene diisoc~7anate (45.7 grams) was added and mixing
continued for 5 seconds whereupon the Eoam began to rise. After
foam rise was completed (about 3 minutes), the foam was post-
cured for 8 minutes in a 120C oven. The ~thus produced foam was
butter vellow in color.
EXAMPLE VII
_. _
Incorporation into a PolYurethane Film
A urethane prepolvmer was prepared from :lO4 grams of a
polyDrop~lene glycol of molecular weight 2000, 22.5 grams of
_g_
~39g~
toluene diisocyanate, 3.2 grams of the red coloring agent of
Example III. To 30 grams of the prepolymer was added 7 drons of
dibutyltin dilaurate and the resulting mixture was cast as a
40 mil fi.lm on ~olyte-trafluoroethylene. A:Eter curing at room
temneratllre overnight, a tough, ~lexib]e "~eep red film ~as
obtained.
r AMPLE VIII
Inco~ration into an E~oxy
To a mixture of 58 grams of an epoxy resin derived from
bis-phenol A with weight per epoxy of about 185 to 192, 54 grams
of methyltetrahydrophthalic anhvdride and 0.66 grams of a
tertiary amine catalvst was added 1 dro~ of the hlue coloring
agent of Example IV. After curing at 110C, a clear blue resin
was obtained.
1 5 _XAMP LE I X ~
Example of Incor~oratio_ i.nto a Polyester
Polyurethane Foam
A mixture of a polydiethylene adipate (equivalent weight
. 1066, 50 grams), N-ethylmorpholi.ne (0.9 grams), N,N-dimethyl-
hexadecylamine (0.05 grams), a mixture of nonionic and anionic
surfactants and the coloran~ of Rxample I ~0.25 grams) was blended
until the components were homogeneous. To this mixture was added
toluene diisocyanate (22,3 grams) and mixing was con-tinued for 5
seconds. The mixture was poured into a container and allowed to
rise forming a ~ellow flexi.ble urethane foam.
E A~1PLE X
Example of Incorporat.ion into a Reaction
In~ection Molding _ _) Fo _ ulation
A mixture was prenared of an acrylonitrile and styrene
modified polyol (equivalent weight 2000, 42.5 grams), a mixture
of sho dlols (equivalent weiqht ~8, 7.5 grams), meth~lene
11~99~0
chloride (1.0 grams), dibutyltin dilaurate (1 drop) and 0.25 gra~s
of the colorant of Example V. 'I'he mixture was blended until
homogeneous. To this mixture was added a modified diphenyl-
methane diisocyanate (equivalent weight 147, 26.6 grams) and
blending continued for 5 seconds to ensure homogeneity. AEter
approximately 15 seconds the mixture rapidly tripled its volume
and cured. The thus formed polymer was deep violet in color.
Upon slicing, it was evident that the color was distributed
evenly throughout the structure.
