1. Field of the Invention
This invention relates to a novel method for the production of a halogen-containing phthalocyanine compound. More particularly, this invention relates to a method for the production of a halogen-containing phthalocyanine compound manifesting the absorption of heat ray and/or the absorption in a near infrared region, excelling in solubility in a solvent, and having excellent light-fastness.
The phthalocyanine compound which is obtained by the method contemplated by this invention excels in a heat ray-absorbing property and, therefore, is useful as a heat ray-absorbing dye. Since the phthalocyanine compound obtained by the method according to this invention absorbs light in a near infrared region having a wavelength in the range of 600-1000 nm, it can manifest excellent effects when it is used as a near infrared absorption dye and a near infrared sensitizer for writing or reading in an optical recording medium using a semiconductor laser, a liquid crystal display device, and an optical character reader, as a photothermal modifier for thermal transfer and a thermal paper, thermal stencil printing, as a near infrared absorption filter as for plasma display panel (PDP), as an asthenopia inhibitor, as a near infrared absorbing material for a photoconductive material, or as a color separation filter for an image pickup tube, as a color filter for liquid crystal display, as a selective absorption filter for a color braun tube, as a color toner, as a toner dye for flash fixing, as an ink jet ink, as an indelible bar code ink, also as a microorganism inactivating agent, as a photosensitive dye for oncotherapy, as a heat ray-shielding agent for automobiles and buildings, and as a discriminating agent for resin sorting.
2. Description of Related Art
The needs for a near infrared absorbent dye have been mounting in consequence of the expansion of the field of the applications thereof. As regards the near infrared absorption dye to be used as a near infrared absorption dye and a near infrared sensitizer for writing or reading in an optical recording medium using a semiconductor laser, a liquid crystal display device, and an optical character reader, as a photothermal modifier for thermal transfer and a thermal paper, thermal stencil printing, as a near infrared absorption filter as for plasma display panel (PDP), as an asthenopia inhibitor, as a near infrared absorbing material for a photoconductive material, or as a color separation filter for an image pickup tube, as a color filter for liquid crystal display, as a selective absorption filter for a color braun tube, as a color toner, as a toner dye for flash fixing, as an ink jet ink, as an indelible bar code ink, also as a microorganism inactivating agent, as a photosensitive dye for oncotherapy, as a heat ray-shielding agent for automobiles and buildings, and as a discriminating agent for resin sorting, methods for the production of materials which satisfy wholly such characteristics as light-fastness, heat-resistance, and solubility (or compatibility with a resin) have been studied hitherto. None of the methods developed to date, however, has proved advantageous for commercial applications.
The methods for producing such phthalocyanine compounds have been disclosed in JP-A-2000-63693, JP-A-2000-169743, JP-B HEI-07(1995)-103318, and U.S. 2003/0234995 A1, for example.
JP-A-2000-69693 discloses a method which comprises inducing the reaction of tetrafluorophthalonitrile with vanadium trichloride by using α-methyl naphthalene or benzonitrile solely while introducing an oxygen-containing gas such as a gas obtained by diluting air into the resultant reaction solution. Since the solvent, α-methyl naphthalene, to be used in this method is very expensive and since the reaction of this method necessitate the introduction of a hot oxygen-containing gas and, therefore, entails a possibility of the introduced gas entraining the expensive solvent and dispersing it outside the reaction system and threatening the danger of explosion, this method hardly deserves to be rated as favorable for commercialization. JP-A-2000-169743 discloses the reaction of tetrafluorophthalonitrile and vanadium trioxide in benzonitrile as a solvent in the presence of paratoluene sulfonic acid and calcium carbonate at 150° C. This official gazette recommends to use as an organic solvent in the reaction an inert substance having no reactivity with the starting materials and the reaction vessel and, for the purpose of preventing the reaction vessel from corrosion, to perform the reaction of a metal oxide and paratoluene sulfonic acid at relatively low temperature. The present inventors' review of this method, however, has revealed that this method is not appropriate because the phthalocyanine compound produced thereby as aimed at occasionally fails to manifest the performance as claimed.
JP-B-HEI 07(1995)-103318 discloses a novel phthalocyanine compound and a method for the production thereof and claims to produce a fluorine-containing phthalocyanine compound by reacting a corresponding phthalonitrile compound with vanadium chloride in an inert solvent or an aprotic solvent. Though only ethylene glycol cited as a reaction solvent is an example of an inert solvent, no other alcohols cannot be found anywhere. The working examples cited therein include the synthesis of phthalocyanine in a current of nitrogen. This synthesis is found to use benzonitrile exclusively as an inert solvent. U.S. 2003/0234995 A1 discloses the reaction of a substituted phthalonitrile compound with vanadium chloride using benzonitrile and octanol under reflux. Since the reaction is effected without using an inert gas such as nitrogen, the yield is as low as 63.2 mol %.