Preparation of chlorinated phthalocyanines

According to the present invention there is provided a process for the production of highly halogenated copper phthalocyanine which comprises heating at an elevated temperature a mixture of copper phthalocyanine, sulfuryl chloride, sulfur monochloride, aluminum chloride and cuprous chloride thereby obtaining a green copper phthalocyanine.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to the chlorination of copper phthalocyanine to 
produce a green shade of copper phthalocyanine. 
2. Description of the Prior Art 
It is well known that the shade of copper phthalocyanine varies according 
to the number of chlorine atoms present in the molecule. Thus the blue 
shade of the unchorinated copper phthalocyanine changes to green-blue when 
8 chlorine atoms are introduced and to a more intense green shade when 12 
or more chlorine atoms are incorporated into the copper phthalocyanine 
molecule. 
In the past, processes for the preparation of phthalocyanine green employed 
large amounts of expensive reagents as solvents such as chlorosulfonic 
acid which are then discarded after the reaction is complete. Such 
processes are expensive due both to the waste of the discarded solvent and 
to long reaction times required to make the phthalocyanine green. 
Chlorinated metal phthalocyanines have been produced by a variety of 
methods. As halogenating agents, it has been proposed to employ normally 
liquid halogenating agents such as sulfuryl chloride and thionyl chloride. 
Such halogen carriers as aluminum chloride are used in limited quantities, 
but the bulk of the reaction medium consists of the liquid halogenating 
agent. In other words, the halogenating agent is dependent upon to supply 
the liquid medium for the reaction. 
U.S. Pat. No. 3,320,276 teaches that sulfuryl chloride will halogenate a 
metal-free phthalocyanine or a metal complex of phthalocyanine such as 
copper phthalocyanine without the addition of elemental halogen in the 
presence of aluminum chloride and/or aluminum bromide and, preferably, 
containing an alkali metal halide such as sodium chloride with sulfur 
monochloride present as a halogen carrier. However, this process requires 
the aluminum chloride or aluminum bromide be in the form of a fluid melt. 
This has many disadvantages since it requires means for heating and 
maintaining the aluminum chloride in a fluid state. Large quantities of 
the aluminum chloride are required in this process, for example, all the 
examples call for 100 parts of anhydrous aluminum chloride for 10 parts of 
copper phthalocyanine. Further, the hydrolyzed aluminum chloride (at the 
end of the reaction) is discarded and may contribute to effluent problems. 
Moser and Thomas, Phthalocyanine Compounds, pages 172-179, Reinhold 
Publishing Corporation, New York (1963), discloses the use of copper 
chloride as a catalyst for chlorinating copper phthalocyanine. However, it 
does not disclose the use of copper chloride in a process involving the 
reaction of the copper phthalocyanine with sulfuryl chloride. 
______________________________________ 
Other References of Interest 
Pat. No. Issued Inventor(s) 
______________________________________ 
2,214,469 9/10/40 Patrick et al 
3,424,759 1/28/69 Stewart et al 
4,077,974 3/7/78 Wessling 
4,091,028 5/23/78 Barraclough et al 
4,035,383 7/12/77 Sweet 
2,873,279 2/10/59 Randall et al 
2,793,214 5/21/57 Holtzman et al 
2,662,085 12/8/53 Holtzman et al 
2,862,924 12/2/58 Caliezi et al 
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SUMMARY OF INVENTION 
It is a purpose of the instant invention to provide a process for 
halogenating copper phthalocyanine using a solvent wherein problems of 
loss due to excessive waste of solvent and to the need for a fluid melt of 
an aluminum chloride or similar catalyst are eliminated or substantially 
reduced. More specifically, this invention relates to a process for the 
halogenation of copper phthalocyanine comprising reacting a mixture of 
copper phthalocyanine, sulfuryl chloride, sulfur monochloride, aluminum 
chloride and cuprous chloride to produce a green shade copper 
phthalocyanine compound. 
DESCRIPTION OF THE PREFERRED EMBODIMENT 
According to the present invention there is provided a process for the 
production of highly halogenated copper phthalocyanine which comprises 
heating at an elevated temperature a mixture of copper phthalocyanine, 
sulfuryl chloride, sulfur monochloride, aluminum chloride and cuprous 
chloride thereby obtaining a green copper phthalocyanine. 
The quantities of sulfuryl chloriide and of sulfur monochloride used as 
well as the amounts of the cuprous chloride and aluminum chloride catalyst 
are important for a satisfactory performance of the process according to 
the invention. The minimum amounts are limited by the amount of catalyst 
necessary to permit the reaction to run to completion in a reasonable 
amount of time (e.g., one day). The maximum amounts are limited by cost 
considerations, i.e., excessive amounts are wasteful. More specifically, 
it is preferred that the mixture prior to the reaction contain by weight 
about 2 to 2000 parts sulfuryl chloride, about 0.05 to 50 parts sulfur 
monochloride, about 0.025 to 25 parts aluminum chloride, and about 0.025 
to 25 parts cuprous chloride per part of phthalocyanine blue. The 
preferred proportions are by weight, about 2 to 100 parts sulfuryl 
chloride, about 0.1 to 5.0 parts sulfur monochloride, about 0.1 to 5.0 
parts aluminum chloride, and about 0.1 to 5.0 parts cuprous chloride per 
part of phthalocyanine blue. 
The most preferred proportions are by weight about 2.0 to 20 parts sulfuryl 
chloride, about 0.1 to 5.0 parts sulfur monochloride, about 0.1 to 5.0 
parts aluminum chloride, and about 0.1 to 1.0 parts cuprous chloride per 
part of phthalocyanine blue. In commercial practice the unreacted sulfuryl 
chloride can be distilled over and recovered for reuse. This provides an 
economic advantage over prior art processes employing chlorosulfonic acid 
as a solvent which is then discarded after the reaction is complete. 
It is possible to vary the temperature at which halogenation may be 
effected within relatively wide limits without departing from the scope of 
the invention. However, a preferred working range of temperature is from 
about 75.degree. to 200.degree. C. and most preferably 90.degree. to 
100.degree. C. The preferred pressure for carrying out the present 
invention, generally ranges from atmospheric to 100 bars, preferably from 
about 5 to 15 bars, and the time required ranges from about 0.5 to 24 
hours and most preferably about 1 to 5 hours at the maximum pressure. In 
general, after the reaction the sulfuryl chloride is removed by 
evaporation. The residue is then slurried in by weight, from about 10 to 
100 parts of water and about 1 to 20 parts by weight sodium bicarbonate 
per part of copper phthalocyanine. 
By means of the instant invention, it is possible to provide a high degree 
of chlorination of the copper phthalocyanine whereby a good green color is 
achieved.

The invention will be illustrated by the following examples in which all 
parts and percentages are by weight and all temperatures are in degrees 
centigrade unless expressly stated otherwise. 
EXAMPLE 1 
To a 250 ml by volumne Berghof Teflon-lined autoclave was added 5 grams of 
sulfur monochloride, 2.5 grams of aluminum chloride, 100 ml of sulfuryl 
chloride, 2.5 grams of cuprous chloride and 10 grams of acid purified 
phthalocyanine blue crude. The reactor was sealed and heating started. 
After about 15 minutes, the pressure was 320 psig and the temperature was 
125.degree. C. Over the next 15 to 20 minutes the reaction reached a 
maximum temperature of 170.degree. C. and a pressure of 900 psig. 
The reactor was then cooled to room temperature, opened, and the sulfuryl 
chloride removed by evaporation. The residue was slurried in 500 ml of 
water and sodium bicarbonate was added until gas (carbon dioxide) 
evolution ceased. The slurry was acidified with sulfuric acid, filtered, 
washed and dried. The yield of green pigment was 17 grams with a chlorine 
content of 43.8 percent (which corresponds to about 12.2 to 12.5 chlorine 
atoms per molecule). This is about 98 percent of theoretical yield. The 
pigment was rubbed up in a vehicle to give a blue shade green that 
appeared to be about equal in strength to a pigment prepared by salt 
grinding a phthalocyanine green crude. 
EXAMPLE 2 
To a 300 ml, three-neck, round bottom flask equipped with stirrer, reflux 
condenser with a drying tube and a thermometer was added 5 grams of sulfur 
monochloride, 2.5 grams anhydrous aluminum chloride and 100 ml of sulfuryl 
chloride. This was mixed and 10 grams of phthalocyanine blue was added. 
After the blue was added, the temperature was slowly raised to reflux 
(about 69.degree. C.) over a 2 hour period. Only enough heat was employed 
to maintain a gentle reflux. Any decrease in the volume of material in the 
flask during reflux was made up with additional sulfuryl chloride and the 
refluxing continued. The sulfuryl chloride was then stripped under reduced 
pressure at room temperature using an iced receiving flask. The residue 
was digested in 500 ml of water and solid sodium bicarbonate added until 
there was no more CO.sub.2 given off. The mixture was then heated to 
100.degree. C. for 1 hour, slowly acidified to a pH of 0.5 to 1 with 
sulfulric acid, filtered and washed until the pH was 6 to 7. 
Phthalocyanine green was not obtained. 
EXAMPLE 3 
Example 2 was repeated except the refluxing step was carried out for 8 
hours rather than for 2 hours. As with Example 2, phthalocyanine green was 
not obtained.