Note: Descriptions are shown in the official language in which they were submitted.
'~is invention relates to p--phelloxybenzotri-
chloride and to the preparation thereof~ The compound
p-phenoxybenzotrichloride is useful as a chemical
intermediate in the preparation of various pesticides
and polymers.
Aromatic polyketone polymers having excellent
melt processability are de~cribed in U.S. patent
4,0~4,314. The preferred monomer for the preparation
of such polyketone polymers is p-phenoxybenzoyl fluoride.
This monomer is prepared by fluorination of p-phenoxy-
benzoyl chloride. Various methods for the preparation
of p-phenoxybenzoyl chloride are known in the litera-
ture. In general the known method pxior processes
which may be employed in the preparation of p-phen-
oxybenzoyl chloride are multi-stepped processes which
are costly and frequently complicated by the presence
of undesirable impurities stemming from undesired side
reactions or from the presence of reactants and/or
catalysts employed.
It has now been found that p-phenoxybenzoyl
chloride may be prepared in excellent yield and high
purity by a novel process involving the usa of a here-
tofore unknown compound, p-phenoxybenzotrichloride.
It has now been found, in accordance with one
aspect of the invention, that the novel compound p-
phenoxybenzotrichloride may be prepared by a process
which comprises the photo-chlorination reaction of p-
phenoxytoluene with chlorine, the reaction may be
carried out in the absence of a solvent or in the
presence of a suitable non-reactive solvent.
In accordance with another aspect of the
inventionJ there is provided a process for the pre-
paration of p-phenoxybenzoylchloride which comprises
reacting p-phenoxybenzotrichloride with a hydrolyzing
reactant,selected from water, aqueous mineral acids,
carbvxylic acids, sulfonic acids, mixtures of lewis
acids with water or carboxylic acids and mixtures
thereof. The p-phenoxybenzotrichloride produced in
~a~r~
- 2 - ~1~.D7~
accordance with the invention may be employed for the
preparation of the p-phenoxybenzoylchloride, thus the
p-phenoxybenzotrichloride may be partially hydrolyzed
by reaction with a suitable acid or by reaction with
water, to produce p-phenoxybenzoylchloride.
In yet another aspect of the invention, there
is provided the novel compound, p-phenoxybenzotri-
chloride. In still another asp~ct the present invetnion
is directed to the preparation of p-phenoxybenzotri-
chloride as a step in the production of p-phenoxy-
benzoylchloride.
~e preparation of p-phenoxybenzotrichloride
is generally accomplished by irradiating mixtures of
the reactants at the desired reaction temperatures
until the desired degree of chlorination has been
achieved. Reaction temperatures are generally in the
range of from about 0Celsius to about 180Celsius and
preferably in the range of from a~out 20CP1SiUS UP to
about the boiling point of the reaction mixture.
The reaction of chlorine with p-p~enoxytoluene
may be carried out neat or, preferably, in the presence
of a non-reactive solvent. Suitable solvents include
benzoic acid or a halogenated hydrocarbon solvent such
as methylene chloride, chlorobenzene, polychlorinated
benzenes and 1,1,2-trichloro-1,2, 2 -trifluoroethane,
which tend to moderate or facilitate the reaction. A
preferred solvent ~or this purpose is carbon tetra-
chloride. It has been found that when carbon tetra-
chloride is employed as a solvent in the present reaction
the tendency toward undesired ring chlorination is
lèssened.
Typically the reaction is carried out by the
addition of chlorine gas or sulfuryl chloride, with or
without suitable catalyst to a suitably heated liquid
3~ reaction medium comprising p-phenoxytoluene in carbon
-- 3 --
tetrachloride solvent. It has been found that undesired ring chlori-
na~ion may occur as full conversion of the p-phenoxybenzotrichloride
intermediate is approached. Accordingly, maximum ylelds ~nd product
purity are achieved by carefully following the progress of the re-
action and stopping the addikion of chlorlne before extensi~e ring
chlorination occurs.
Actinic light is employed for promoting the chlorination reaction.
Any of the well known light sources which will accelerate the chlori-
nation of p-phenoxytoluene may be used, such as ~ungsten filament
lamps, ultraviolet lamps, mercury vapor arc lamps, fluorscent lamps,
ordinary light bulbs, and the l~ke. The preferred irradiation ~s an
; ultraviolet l~ght source.
The compound p-phenoxybenzotrichloride is a white crystalline
sol~d at ordinary temperatures, hav~ng a melting point af about
48-49.~0 Celsius, and thus ~s readily purified by fractional cry-
stallization and distillation.
The crystall;zation can bc achieved by partial crystall kation
of the neat materi~l or by crystalli~ation from a suitable solvent.
Distillation is pre~erably run under reduced pressure.
The p-phenoxybenzotrichloride may be partially hydrolyzed to
form p-phenoxybenzoylchloride in high yields. The hydrolyzation
can be affected by a hydroxy danating system, catalyzed or non-
catalyzed, which dona$es an oxygen by replacement of two of the
chlorines from the trichloromethyl group withou~ forming an adduct
with the desired acid chloride product. The following compounds
have been found effective in hydrolyzing p-phenoxyben70trichloride
to p-phenoxybenzoylchloride: organic acids, including substituted
and unsubstituted aliphatic mono~ and di- carboxylic acids, such
as acetic, propionic, bu~yric, maleic, adipic, gluteric and malonic
acids as well as substituted and unsubstituted aromatic mono- and
di- carboxy~ic acids such as benzoic, p-phenoxybenzoic9 terephthalic,
isophthalic and phthalic acids; aqueous mineral acids, such as hydro-
chloric9 hydrobromic, hydroiodic and hydrof1uoric acids as well asdilute su1Furic and phosphoric acids, water; sulfur~c acids such as
methane sul~onic acid, benzene su1fonic acid, toluene sulfonic acid
and the like; m;xtures o~ Lewis acids, e.g. ferric chlorider aluminum
chloride and ~inc chloride, with water and/or the afore identified
organic acids; and, mixtures thereof. Thus, in one embodiment, p-
phenoxybenzotrichlor~de is contacted with an approx;mately e~uimolar
amount of water. The amoun~ of water may vary somewhat but ~s pre-
ferably within about 10% of the equirnolar amount. Lesser amounts
wi~l result in lower yields of the p phenoxybenzoylchloride and
greater amounts will result in a degree of hydrolysis to p-phenoxy-
benzoic acid. The reaction may be carried out at temperatures of
about room temperature (about 20 ~elsius) and higher and will proceed
most readi1y with external heat at a temperature in excess of about
100 Cels;us and preferably at a tempera~ure in the range of about 130
to about 150 Celsius. Under autogenous pressure higher temperature
may be employed, however, temperatures in excess of about 180 Cels;us
provide little advantage and are not preferred. In a preferred mode
it has been found that the incorporat;on of hydrochloric acid in the
startinQ react;on medium, facil;tates partia~ hydrolysis reaction
with the unexpected advantage of 7ess stringent temperature require-
ments. The amount of hydrochlor;c acid employed~ based on hydrogen
ch1Oride content, may vary considerab1y. Conveniently, concentrated
hydrochloric acid ;s employed in an amount suffic;ent to provide the
desired molar amounts of water. L~sser strengths of hydrochloric
acid may be employed if desired. Preferred temperature in this mode
is in ~he range of about 70~ to about 110 Celsius.
Alternatively the partia7 hydrolysis of p-phenoxybenzotrichloride
may be effected by reaction with a mono- or di- carboxylic acid to
produce a mixture of p-phenoxybenzoylchloride and an ac;d chloride
derived from the carboxylic acid employed. A wide variety Df carbox-
ylic acids may ~e employed including both aliphatic and aromatic car-
boxylic acids. The reaction proceeds to high yields in an unexpectedly
- s -
facile manner at ambient temperature and without the need for a cata-
lyst. Higher temperatures may be employed but are not required. In
a particularly advantageous mode, p-phenoxybenzoic acid is emplsyed
as the carboxylic acid with the result that no co-product is formed
S since both reactants are converted in the reaction to the desired
- product p-phenoxybenzoylchloride.
The proportions of carboxylic ac~d employed may vary, but are
preferably within about 10~ of the equimolar amount based on the p-
phenoxybenzotrichloride reactank.
In one mode of the ;nvention the p~phenoxybenzotrichloride was
completely hydrolyzed with water alone, or an aqueous base such as
KOH, and a suitable co-solYent such as ac~tone or isopropyl alcohol
to form the p-phenoxybenzoic acid, or salt thereof (which may then
be neutralized to the acid~, and then chlor;nated, for example with
thionyl chloride, to form the desired p-phenoxybenzoyl chloride.
The following specific examples are provided to furth~r illus-
trate this invention and the manner in which it may be carried out.
It will be understood. however, that the specific details given in
the examples have been chosen for purpose of i11ustration and are
not to be construed as a limitation on the invention. In the ex-
amples, unless otherwise indicated, all parts and percentages are
by weight and all temperatures are in degrees Celsius.
EXAMPLE 1 - Prepara~ion of P-Phenoxybenz~trichloride
Ten parts of p-phenoxytoluene containing about 0.2% of N,N-di-
methyl caproamide (a sequestering agent to remove any traces of iron)was charged to a reaction vessel and heated to about 120 C. The
temperature was maintained at about 120 C. while the react;on mix-
ture was ;rrad;ated with a mercury arc lamp and approximately 12 parts
of chlorine were sparged into the mixture over a period of 4 hours.
The progress of the reaction was monitored with periodic sampling and
analysis and the chlorine flow was stopped when over-chlorination
(i.e., ring chlorination) was observed. Product samples were treated
with CaO/Na2S202, filtered, and analyzed by gas chromatographic tech-
n;ques. The yield of p-phenoxybenzotrichloride was 20% based on p-
phenoxytoluene starting material.
EXAMPLE 2 - Preparation of P-Ph _oxybenzotrichlorîde
A mixtune Qf 5.0 parts of p-phenoxytoluene and 0.02 parts of
N3N-dimethyl caproamide in 21~3 parts o~ carbon tetrachloride was
charged to a reaction vessel ~nd heated to about 95~ C~ The reaction
S mixture was irradiated with a mercury arc lamp and the temperature
maintained at about 95 C. while about 54 parts of ch7Orine were
sparged înto the mixture over a period of about 3.5 hours. The pro-
gress of the reaction was monitored by periodic samplin~ and analysis
and the chlorine flow was stopped when over-chlorination was observed
19 Product samples were treated with CaO/Na2S202, filtered and analyzed
by gas chromatographic techniques. The yield of p-pheno~ybenzotri-
chlor;de, was greater than 70~, based on p-phenoxytoluene starting
material.
Samples of the p-phenoxybenzotrichloride prepared by the methods
of Examples 1 and 2 were purified by fractional crystalliza~ion from
heptane and acetonitrile. The purified samples were characterized
by a melting point of about 48-49.50 C. and mass spectural data
confirmed a molecular structure of C13HgC130.
EXAMPLE 3 - Preparation ~f P-Phenoxybenzoylchloride_
A mixture of ~.7~ parts of p-phenoxybenzotrichloride and 0.36
parts of water was charged to a reactiQn vessPl and gradually heated.
Reaction was observed to occur as the temperature ~ the mi~ture
approached 120 C. with a rapid increase as the temperature app-
roached 140 C. The reaction mixture was maintained at about 140 C.
for about nne hour, then vacuum stripped and the product analyzed by
gas chromatographic techniques. Analysis (in area percent~ indicated
83X p-phenoxybenzoylchloride and 9% of the p-phenoxybenzotrichloride
starting materia7.
EXAMPL _4 - PreParation of P-Phenoxybenzoylchl _ide
3~ A mixture of 5.75 parts of p-phenoxybenzotrichloride and 0.58
parts of concentrated (37%) hydrochloric acid (containing 0.36 parts
~J,;3~ .$1~
- 7 -
of water) was charged ~o a reaot;on vessel and heated slowly. As
the temperature approached 78~ C~, reaction was obserYed with
evolution of HCl. Continued hea~ing at ~emperatures o~ about 80~-
85~ C. was ma;ntained for about two hnurs. Analysis of the product
by nas chromatographic techniques indicated 36.0~ of p-phenoxy-
benzoylchloride and 24.5% of p-phenxoybenzotrichloride start1ng
material.
EXAMPLE 5 - Preparation of P-Phenoxybenzoylchloride
P-phenoxybenzotrichloride (288 parts) was added to 182 parts of
p-phenoxybenzoic acid, with mixing. The mixture was allowed to stand
a~ ambient temperature for about 16 hours, then heated, over a period
of about 4 hours, to a temperature of about 140~ C., ~t which point
HCl evolution was detected. The m~xture was maintained at a tempe~
rature of between abou~ 112 and 140 C. for an additional 21 hours,
then cooled and analyzed by gas chromatoyraphic techniques. Analysis
indicated a 73% yield of p-phenoxybenzoylchloride based on the start-
ing mater~als.
EXAMPLE 6 - Preparation of P-Phenox~benzoylchloride
A mixture of 5.75 parts of p phenoxyhenzotrichloride and 2.44
parts of benæoic acid was charged to a reaction vessel and heated to
about 140~ C. over a period of about one huur, at which point the
evolution of HCl from the reaction mixture was ohserved. The mixture
was maintained at about 120 to about 140 C. for an additional
hours, then c~olPd and analy7ed by gas chromatographic techniques.
Analysis indicated 19.9% p-phenoxybenzoY~chloride~ and 8.3~ benzoy7-
ch10ride.
EXAMPLE 7 - Preparation of P-Phenoxybe ~
Acetic acid ~2.1 parts) was mixed with p-phenoxybenzotrich70ride
(lO parts) and the mixture was allcwed to stand at ambient conditions
for abou~ 64 hours. Analysis of the mixture by C13 NMR analysis,
in relative mole X, indicated Ç8% p-phenoxybenzoylehloride and 19%
p-phenoxybenzotrichloride.
