Processing for washing-out degradation-resistant organic chlorin

Details Processing for washing-out degradation-resistant organic chlorin Processing for washing-out degradation-resistant organic chlorin

1998-09-08

2000-01-25

Wilson, James O.

Organic compounds -- part of the class 532-570 series

Organic compounds

Heterocyclic carbon compounds containing a hetero ring...

5483261, 570204, 570190, 4741161, 4741164, 474181, C07D23328, C07D23330

Patent

active

06018051&

DESCRIPTION:

BRIEF SUMMARY
TECHNICAL FIELD

This invention relates to a chemical treatment process for safely washing a degradation-resistant organic chlorine compound out of a cellulose-containing material having the degradation-resistant organic chlorine compound adhered thereto.


BACKGROUND ART

Pressure-sensitive papers with adhered polychlorobiphenyl (PCB) and other degradation-resistant organic chlorine compounds (hereinafter PCB etc.) remain in storage for the lack of a safe process for treating the pressure-sensitive paper. On the other hand, methods for draining transformers, oil capacitors and other electrical equipment of PCB etc. and then washing them with a solvent such n-hexane are being promoted. However, removal of PCB etc. adhering to the paper, wood and the like incorporated in such electrical equipment and the like is extremely difficult and no safe treatment process for this purpose has yet been discovered.
Since n-hexane and other such solvents have low viscosity and are excellent solvents of PCB etc., the ordinary washing operation is highly effective for washing metals, plastics and the like, only requiring that care be taken regarding the low solvent ignition point. PCB etc. remaining after recovery of n-hexane or the like from the washing solution can therefore be safely and completely broken down by the method under the inventors' earlier application (Japanese Patent Public Disclosure Hei 7-8572). However, a treatment process using n-hexane or the like cannot completely extract and break down PCB etc. adhering to paper, wood or other such materials containing cellulose.
The object of this invention is therefore to provide a washing and removal process which completely extracts and breaks down PCB etc. from a cellulose-containing material having adhered PCB etc.


DISCLOSURE OF THE INVENTION

Having discovered through many years of research into chemical extraction and decomposition of PCB etc. that this can be completely achieved by using a strong alkali in a special aprotic solvent, the inventors filed several patent applications (Japanese Patent Public Disclosure Nos. 7-289656 and 7-313620). They also ascertained that these inventions exhibit a dramatic effect in efficiently washing PCB etc. out of a cellulose-containing material having adhered PCB etc., whereby they accomplished this invention.
Specifically, the process for washing out PCB etc. according to this invention is characterized in bringing a cellulose-containing material having the PCB etc. adhered thereto into contact with a strong alkali in a solution containing not less than 50% of one of 1,3-dimethyl-2-imidazolidinone (hereinafter DMI) and sulfolane or a mixture of these two aprotic solvents.
The inventors learned through a long series of experiments that PCB etc. are dramatically removed when a cellulose-containing material having adhered PCB etc. is contacted with a strong alkali in an alkali-resistant, high-boiling-point solvent containing not less than 50% of one of DMI and sulfolane or a mixture of these two solvents.
With regard to this invention, "PCB etc." refers to, for example, polychlorobiphenyl (hereinafter PCB), polychlorodioxin, polychloroterphenyl, polychloronaphthalene, polychlorobenzene derivative, and mixtures of these. With regard to this invention, "cellulose-containing material having adhered PCB etc." refers mainly to, for example, paper, formed articles of copper and aluminum such as wire, thin sheet and the like used in transformer coils and other such electrical equipment, and bamboo and other woods used as support materials in such electrical equipment. The cellulose-containing material having adhered PCB etc. may also of course be cotton cloth or linen cloth contaminated by adherence of PCB etc. The term cellulose-containing material having adhered PCB etc. also encompasses pressure-sensitive paper, such as business forms, made of paper coated with microcapsules containing a mixture of PCB etc. and coloring dye.
With regard to this invention, "alkali" refers to caustic soda, caustic potash, sodium alcoholate, po

REFERENCES:
patent: 4447541 (1984-05-01), Peterson
patent: 4853040 (1989-08-01), Mazur et al.
patent: 5648499 (1997-07-01), Tanimoto et al.
Patent Abstracts of Japan, publication No. 07289656A, dated Nov. 7, 1995.
Patent Abstracts of Japan, publication No. 07313620A, dated Dec. 5, 1995.

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