Title of Invention	"AN IMPROVED PROCESS FOR THE PREPARATION OF METAL COMPLEX-MONTMORILLONITE COMPOSITE USEFUL AS DEODORANTS"
Abstract	The present invention relates to an improved process for the preparation of metal complex - montmorillonite composite useful as deodorants. The process of the present invention relates to pillaring of expandable layered clay like montmorillonite by stable cationic responsible for arresting hydrogen sulflde, ammonia etc. from air. This invention is more particularly related to preparing efficient porous deodorants to purify indoor air/refrigerator or the like from polluting gases like hydrogen sulflde ammonia etc.

Title of Invention

"AN IMPROVED PROCESS FOR THE PREPARATION OF METAL COMPLEX-MONTMORILLONITE COMPOSITE USEFUL AS DEODORANTS"

Abstract

The present invention relates to an improved process for the preparation of metal complex - montmorillonite composite useful as deodorants. The process of the present invention relates to pillaring of expandable layered clay like montmorillonite by stable cationic responsible for arresting hydrogen sulflde, ammonia etc. from air. This invention is more particularly related to preparing efficient porous deodorants to purify indoor air/refrigerator or the like from polluting gases like hydrogen sulflde ammonia etc.

Full Text	The present invention relates to an improved process for the preparation of metal complex -montmorillonite composite useful as deodorants. More particularly, the process of the present invention relates to pillaring of expandable layered clay like montmorillonite by stable cationic metal complex and then exchanging with potent transition metal cations responsible for arresting hydrogen sulfide, ammonia etc. from air. This invention is more particularly related to preparing efficient porous deodorants to purify indoor air/refrigerator or the like from polluting gases like hydrogen sulfide ammonia etc. Hydrogen sulfide, ammonia and other similar gases, generated by decomposition of proteins and/or by other means pollute the air. Such polluting gases are harmful to animal as well as plant kingdom. Therefore, removal of such gases at least from indoor or refrigerator or from any closed room is essential or to bring the concentration well below the pollution level. Several types of deodorants have been developed to arrest such polluting gases from the air. In general such deodorants are mostly prepared by supporting transition metal salts on supports like activated charcoal, zeolites, silica gel, diatomaceous earth, bentonite clay, fiber etc. Japanese Patent application No. 63-220872 (1988) discloses the preparation of deodorants effective against polluting gases generated from fish, meat, or sulfur compounds etc. which consists of fibrous supports like those of traditional Japanese made paper and ordinary paper, fabrics, glass fibre etc. including 5-40 wt. % (to the wt. of the support) of one or more of CaSO4, FeS04, ZnSO4 and MgSO4. Such deodorants are in general less effective in removing the odorous compounds from air. Another Japanese (Patent application No. 63-186656 (1988).... discloses preparation of deodorants for ammonia, amine, hydrogen sulfide, mercaptans; which comprises Zn compounds or Cu(II) compounds with different anions supported on porous zeolite or activated charcoal etc. Zn/Cu ions form coordination complex with ammonia and amines or metal sulfide compounds CuS/ZnS with hydrogen sulfide, mercaptans or alkylsulfides. The active species responsible for arresting the polluting gases are less strongly anchored on the supports and also less uniformly distributed over the entire surface and hence are less effective for using as deodorants. Japanese Patent application No. 62-155935 of 1987 discloses the preparation of deodorant based on swellable mica layers. Alkali ion among the layers are substituted by metal ions like T14+, A13+, Zn2+ etc. through ion exchange to form substituted compounds. Solid acids is preparted among the layers by dehydrating or heating the substituted compounds. The deodorants are used to remove smell of H2S, NH3 and mercaptans. The action of such deodorants is due to neutralization of the basic polluting gases by the solid acid and adsorbed in the interlayers. Such deodorants exhibit very small interlayer gap and therefore may find limited use. In another invention (Japanese Patent application No. 63-249565 of 1988) the preparation of deodorants are described where layered smectite group minerals are loaded with metal ions like Cu2+, Co2+, Cd2+, Ag+ asnd Zn2+ or their hydroxide or oxide compounds. Thus for example Cu(N03)2 aqueous solution was blended with laponite XIG (a synthetic smectite group minerals) and then settled to give a precipitate, which was filtered, washed and dried at 80°C and pulverized to obtain a deodorant with light blue color. Such deodorant is claimed to be efficient in arresting H,S and mercaptan gas adsorption. This invention is based on expandable matrix i.e. lamellar structure of clay consisting layers which upon hydration get separated and ultimately cause expansion as a whole. Normally, such expandable layered materials though effective as deodorants, the free access of the polluting gases like ammonia, hydrogen sulfide or bigger sized molecules etc. are restricted since the interlayer gap is very small or filled with aqueous phase at room temperature. Therefore, use of lamellar support, if not pillared to increase the interlayer gap, show limitations of space for accommodating adsorbed species. Other inventions (Japanese Patent application No. 63-054935 of 1988 and US Patent No. 5108739 of 1992) disclose the preparation of white powder deodorant which consists of an aggregate of close bonding body grain of ZnO, TiO2 and H2O. The ratio of ZnO and TiO2 is in 1:9 - 9:1 or 3:7 - 7:3 by mol ratio. Preparation of such deodorants comprises mixing an alkaline solution and mixed aqueous solution containing water soluble titanium (like titanium sulphate, chloride, nitrate etc.) and water soluble zinc compounds (like zinc sulphate, chloride, etc.) to give solution with pH 6 - 11. A precipitate is formed at 40 - 60°C, which is separated from the mixed solution, and dried at 150-220°C. A white fine powder which consist of ZnO and Ti02 is obtained. The deodorant is stable up to 400°C. Such deodorants are useful for bad smell gas like H2S, NH3 etc. These type of deodorants exhibit low surface area and hence are not much effective. The main objective of the present invention is to provide an improved process for the preparation of metal complex - montmorillonite composite useful as deodorants. Accordingly, the present invention provides an improved process for the preparation of metal complex-montmorillonite composites useful as deodorants which comprises; treating purified bentonite clay with sodium salt to obtain sodium montmorillonite, partially exchanging (10 to 50% of the cation exchange capacity) the Na+ ions with stable three dimensional cationic metal complexes having formula [M(L-L)]n+ where M = Ni and L-L = 1,10-phenanthroline, 2,2'-bipyridine, exchanging the rest (50 to 90% of cation exchange capacity) Na+ ions with Mn+ cations where Mn+ = Cu++, Cd ++ by conventional methods as herein described to obtain the Mn+-[M(L-L)]n+ -montmorillonite composites, drying at temperature in the range of 50 to 250°C for a period 30 minutes to 8 hours, pulverizing by known methods to obtain metal complex - montmorillonite composites, characterized in that in the steps, treating purified bentonite clay with sodium salt and exchanging the Na + ions with three dimensional cationic metal complex. The oxidic compositions of the Bentonite clay is given below (Table 1) Table 1, Chemical composition of Bentonite (Table Removed) In an embodiment of the present invention, the bulky cationic metal complex is selected from any octahedral or tetrahedral or the like three dimensional cationic metal complexes. In another embodiment of the present invention, the requirement of the cationic metal complex may be only about 10% of the cationic exchange capacity of the bentonite clay. In yet another embodiment of the present invention, the metal cations to be used are from transitional and / or non-transition metal groups. Purification of Bentonite (Montmorillonite): The above Bentonite powder was purified by standard gravity settling technique and the -2 µm fraction was collected in order to obtain the montmorillonite fraction. About 20 g of Bentonite was suspended in 1000 ml distilled water by stirring for half an hour and was set aside for about 24 hrs. The suspension up to 10 cm height from the top of the surface of the suspending liquid was collected for -2µ m particle size. The mass was then dried above 50 C in air oven. This fraction of the clay was rich in montmorillonite. Conversion into Na-montmorillonite: The purified clay contains cations like Ca++ and Na+ in the interlayers as exchangeable form. As Na+ is readily exchangeable, the clay is converted into Na-montmorillonite form by treating with NaCl solution. About 2 g of dry purified clay was suspended into 100 ml of distilled water and to it 100 ml of 2 M NaCl solution was added and kept stirring for about 12 hrs. The mass was allowed to settle and the supernatant liquid was decanted of. The slurry was again treated with NaCl solution and stirred. This step was repeated for about 4 times. The excess NaCl was removed by washing with distilled water and finally dialysed till the conductivity of water is The dialysed Na-montmorillonite was identified by measuring the basal spacing (doo1) by XRD technique. Oriented film was prepared on glass slide by allowing about 1 ml suspension to dry at room temperature. The basal spacing of about 12 Å was observed for air dried sample. The slide was then kept in a desiccator over ethylene glycol for about 12 hrs. The d001 value obtained at 16.5 A indicated the identification of montmorillonite clay. Cation Exchange Capacity (CEC): About 0.5 g of the clay was treated with 4 times of CEC(range 80-130 meq. / 100 g clay) of CaCl2 (alcoholic) solution and kept overnight under stirring condition. The difference in the concentration of CaCl2 gave the amount of Ca++ exchanged. The value as determined for the clay was 114 meq. /100 g of clay. Preparation of the Metal complexes : The complexes (M(L-L)3]X where M = Ni, L-L = 1.10- phenanthroline 2,2'-bipyridine, X = S04 were prepared and crystallized by known methods. And the metal salts MX2 (M = Cu, Cd etc, X = Cl) used were of analytical grade. Swelling/expandable clays like smectite group of clays particularly montmorillonite clay has been selected as supporting inorganic solid matrix because of its physico-chemical characteristics. Montmorillomte is composed of layered lattice structure and each sheet is composed of octahedral alumina sandwiched by two tetrahedral sheets of silica. The negative charge on the surface of these layers are, in general, developed by the isomorphous substitution of alumina in octahedral layer by lower valent cations like magnesium or iron. These negative charges are then counter balanced by exchangeable cations like Na+ , Ca++ , Mg++ residing mostly in the interlayer space. These layered structures enable intercalation of other compounds of different characteristics between the sheets of the clay. Water, having the solvation energy higher than the combination of van der Waals attraction between the clay layers and the electrostatic forces generated by the interlayer exchangeable cations both of which oppose interlayer expansion, expands the layers. Upon heating at about 150 ºC, most of the interlayer water is lost and the layers of the clay approach closer to each other and leave very narrow interlayer space and heating at about 250 - 300º C, the interlayer cations diffuses into the layer matrix and the layers are collapsed. The basal spacing i.e. the distance from the top of a layer to the top of the immediate layer, of Na-exchanged montmorillonite dried at 110 °C for 2 hrs., show a value of about 12 Å. This basal spacing for a fully collapsed matrix is about 9.6 A i.e. the layer thickness. The cation exchange capacity (CEC) of such montmori- llonite clay ranges from 80 to 130 meq. / 100 g clay. Therefore, if the interlayer cations are exchanged with bigger sized tree dimensional cationic metal complex like [Ni(phen/bipy)3]++ having a diameter about 7 Å (in C3 axis), the basal spacing obtained is about 17Å even after heating at about 500° C. Thus, an expansion of the layers by about 7Å is possible by such pillaring metal complex and is dependent upon the dimension of the three dimensional species. Of course, pillaring by other species like hydroxy alumina or the likes are well known. Therefore, Na-montmorillonite is subjected to partial (10-50% of the CEC) exchange with bulky cationic metal complex [Ni(phen/bipy)3] ++ to give a homogeneous intercalated metal complex-montmorillonite exhibiting about 17 Å basal spacing (d001). The intercalated product is further ion exchangedi.e. left out 50 - .80 % cations (Na )are exchanged with multivalent cations Mn+ like Cu ++ , Cd ++ etc. THE resulting Mm+ -[Ni(phen)3] ++ -montmoillonite still show the basal spacing value at about 17 Å even after drying over 200° C. Such composite materials are very much potent in respect of developing Bronsted and Lewis acids. Bronsted acidity is developed due to the exchanged metal cations which polarize interlayer water molecules. Partial dehydration increases the acidity, but the acidity of Na+ ion is not high. When the interlayer water is lost due to heating at higher temperature, the metal ion exchanged montmorillonite behaves as Lewis acids. These types of acidity of the solid composites are very useful as acid catalysts in organic synthesis. In the present investigation, the acidic characteristics of the composites will be primarily utilized for neutralizing bases like amines etc. from the air borne gases. Again, the cations remain in the interlayer space can react with H2S or other sulfur containing compounds and retain strongly into the interlayer spacing. Besides, some of the cations will form coordination complexes with the polluting gases like NH3 present in air under suitable condition. Therefore, partially intercalated (pillared) with cationic metal complex-metal ion exchanged montmorillonite can offer considerably high interlamellar space for free access of smaller to bigger molecules having dimension below 7Å and thus may prove to be an effective deodorants for a variety of polluting gases based on sulfur, nitrogen or the likes. The following examples are given by way of illustrations of the present invention and should not be construed to limit the scope of the invention. Example 1 : About 0.5 g of -2 µm fraction of dried Na-montmorillonite clay was dispersed in about 200 ml of distilled water under constant stirring and then mixed thoroughly under ultrasonic vibration for about 10 min. To this homogeneous suspension, a solution (2.5 ml containing 0.039 g of [Ni(phen)3]SO4) was added and stirred for about 30 min. The mass was centrifuged (rpm 12000) for about 15 min. and then washed with distilled water. The mass collected was again dispersed in about 200 ml distilled water under ultrasonic condition for about 10 min. and about 0.038 g of CuCl2 was added and stirred for about 24 hrs and centrifuged to remove the supernatant liquid. This step was repeated for about three times. Finally, the mass was washed with distilled water and dried at 50 °C for 8 hours or at 250°C for 30 minutes. The color of the product was light bluish and kept in air tight bottle. Upon contacted with H2S gas, the composite turns into a blackish solid due to forming a CuS compound. Again, upon contacted fresh composites with NH3 gas, it turns into a bluish colored solid which was due to the formation of [Cu(NH3)4]++ complex into the interlamellar spacing. Example 2 : About 0.5 g of -2µm fraction of dried Na-montmorillonite clay was dispersed in about 200 ml of distilled water under constant stirring and then mixed thoroughly under ultrasonic vibration for about 10 min. To this homogeneous suspension, a solution (2.5 ml containing 0.039 g of [Ni(phen)3]SO4) was added and stirred for about 30 min. The mass was centrifuged (rpm 12000) for about 15 min. and then washed with distilled water. The mass collected was again dispersed in about 200 ml distilled water under ultrasonic condition for about 10 min. and about 0.052 g of CdCl2 in 2 ml water was added and stirred for about 24 hrs and centrifuged to remove the supernatant liquid. This step was repeated. Finally, the mass was washed with distilled water and dried at 50º C for 8 hours or at 250º C for 30 minutes. The product was then kept in air tight bottle. Upon contacted with H2S gas, the composite turns into a yellowish solid due to formation of CdS compound. Example 3 : About 0.5 g of -2 µm fraction of dried Na-montmorillonite clay was dispersed in about 200 ml of distilled water under constant stirring and then mixed thoroughly under ultrasonic vibration for about 10 min. To this homogeneous suspension, a solution (2.5 ml containing 0.099 g of [Ni(phen)3]SO4) was added and stirred for about 30 min. The mass was centrifuged (rpm 12000) for about 15 min. and then washed with distilled water. The mass collected was again dispersed in about 200 ml distilled water under ultrasonic condition for about 10 min. and about 0.024 g of CuCl2 was added and stirred for about 24 hrs and centrifuged to remove the supernatant liquid. This step was repeated for about three times. Finally, the mass was washed with distilled water and dried at temperature 50 ºC for 8 hours or at 250º C for . 30 min. The color of the product was light bluish and kept in air tight bottle. Upon contacted with H2S gas, the composite turns into a blackish solid due to forming a CuS compound. Again, upon contacted fresh composites with NH3 gas, it turns into a bluish colored solid which was due to the formation of [Cu(NH3)4]++ complex into the interlamellar spacing. Example 4 : About 0.5 g of -2 µm fraction of dried Na-montmorillonite clay was dispersed in about 200 ml of distilled water under constant stirring and then mixed thoroughly under ultrasonic vibration for about 10 min. To this homogeneous suspension, a olution (2.5 ml containing 0.099 g of [Ni(phen)3]SO4) was added and stirred for about 30 min. The mass was centrifuged (rpm 12000) for about 15 min. and then washed with distilled water. The mass collected was again dispersed in about 200 ml distilled water under ultrasonic condition for about 10 min. and about 0.032 g of CdCl2 was added and stirred for about 24 hrs and centrifuged to remove the supernatant liquid. This step was repeated for about three times. Finally, the mass was washed with distilled water and dried at temperature 50°C for about 8 or at 250°C for 30 min. The product was kept in air tight bottle. Upon contacted with H.S gas, the composite turns into a yellowish solid due to formation of CdS compound. Example 5: About 0.5 g of -2µ m fraction of dried Na-montmorillonite clay was dispersed in about 200 ml of distilled water under constant stirring and then mixed thoroughly under ultrasonic vibration for about 10 min. To this homogeneous suspension, a solution (2.5 ml containing 0.035 g of [Ni(bipy)3]SO4) was added and stirred for about 30 min. The mass was centrifuged (rpm 12000) for about 15 min. and then washed with distilled water. The mass collected was again dispersed in about 200 ml distilled water under ultrasonic condition for about 10 min. and about 0.038 g of CuCl2 was added and stirred for about 24 hrs. and centrifuged to remove the supernatant liquid. This step was repeated for about three times. Finally, the mass was washed with distilled water and dried at temperature 50 ºC for about 8 hours or at 250 ºC for 30 min. The color of the product was light bluish and kept in air tight bottle. Upon contacted with H2S gas, the composite turns into a blackish solid due to formation of CuS compound. Again, upon contacted with NH3 gas, the composite turns into a bluish colored solid which was due to the formation of [Cu(NH3)4]++ complex into the interlamellar spacing. Example 6 : About 0.5 g of -2 µm fraction of dried Na-montmorillonite clay was dispersed in about 200 ml of distilled water under constant stirring and then mixed thoroughly under ultrasonic vibration for about 10 min. To this homogeneous suspension, a solution (2.5 ml containing 0.035 g of [Ni(bipy)3]SO4) was added and stirred for about 30 min. The mass was centrifuged (rpm 12000) for about 15 min. and then washed with distilled water. The mass collected was again dispersed in about 200 ml distilled water under ultrasonic condition for about 10 min. and about 0.052 g of CdCl2 in 2 ml water was added and stirred for about 24 hrs and centrifuged to remove the supernatant liquid. This step was repeated. Finally, the mass was washed with distilled water and dried at temperature 50º C for about 8 hours or at 250 ºC for 30 min. The product was kept in air tight bottle. Upon contacted with H2S gas, the composite turns into a yellowish solid due to formation of CdS compound. Example 7 : About 0.5 g of-2 µm fraction of dried Na-montmorillonite clay was dispersed in about 200 ml of distilled water under constant stirring and then mixed thoroughly under ultrasonic vibration for about 10 min. To this homogeneous suspension, a solution (2.5 ml containing 0.088 g of [Ni(bipy)3]SO4) was added and stirred for about 30 min. The mass was centrifuged (rpm 12000) for about 15 min. and then washed with distilled water. The mass collected was again dispersed in about 200 ml distilled water under ultrasonic condition for about 10 min. and about 0.024 g of CuCl2 was added and stirred for about 24 hrs and centrifuged to remove the supernatant liquid. This step was repeated for about three times. Finally, the mass was washed with distilled water and dried at temperature 50 C for about 8 hours or at 250 ºC for 30 min. The color of the product was light bluish and kept in air tight bottle. Upon contacted with H2S gas, the composite turns into a blackish solid due to formation of CuS compound. Again, upon contacted with NH3 gas, the composite turns into a bluish colored solid which was due to the formation of [Cu(NH3)]4++ complex into the interlamellar spacing. Example 8 : About 0.5 g of -2 µm fraction of dried Na-montmorillonite clay was dispersed in about 200 ml of distilled water under constant stirring and then mixed thoroughly under ultrasonic vibration for about 10 min. To this homogeneous suspension, a solution (2.5 ml containing 0.088 g of [Ni(bipy)3]SO4) was added and stirred for about 30 min. The mass was centrifuged (rpm 12000) for about 15 min. and then washed with distilled water. The mass collected was again dispersed in about 200 ml distilled water under ultrasonic condition for about 10 min. and about 0.032 g of CdCl2 was added and stirred for about 24 hrs and centrifuged to remove the supernatant liquid. This step was repeated for about three times. Finally, the mass was washed with distilled water and dried at temperature 50º C for about 8 hours or at 250 ºC for 30 min. The product was kept in air tight bottle. Upon contacted with H2S gas, the composite turns into a yellowish solid due to formation of CdS compound. The main advantages of the present invention are 1. The products can arrest large three dimensional odorous / non-odorous molecules. 2. The products can provide sufficient space (at least 7-8 A gap between the layers) for accommodating coordination compounds formed in-situ by the reaction between the metal cations and the coordinating gaseous molecules. 3. The product can provide higher surface area for efficient adsorption. 4. The products can provide desired interlamellar space-gap (tailor-made) for adsorbing selective polluting gases. 5. The products can be utilized for other purposes particularly for suitable catalytic reactions. We Claim: 1. An improved process for the preparation of metal complex-montmorillonite composites useful as deodorants which comprises; treating purified bentonite clay with sodium salt to obtain sodium montmorillonite, partially exchanging (10 to 50% of the cation exchange capacity) the Na+ ions with stable three dimensional cationic metal complexes having formula [M(L-L)]n+ where M = Ni and L-L = 1,10-phenanthroline, 2,2'-bipyridine, exchanging the rest (50 to 90% of cation exchange capacity) Na+ ions with Mn+ cations where Mn+ = Cu++, Cd ++ by conventional methods as herein described to obtain the Mn+-[M(L-L)]n+ - montmorillonite composites, drying at temperature in the range of 50 to 250°C for a period 30 minutes to 8 hours, pulverizing by known methods to obtain metal complex - montmorillonite composites, characterized in that in the steps, treating purified bentonite clay with sodium salt and exchanging the Na + ions with three dimensioned cationic metal complex. 2. An improved process as claimed in claim 1 wherein the bulky cationic metal complex is selected from hexagonal or tetrahedral cationic or any three dimensional cationic metal complex. 3. An improved process as claimed in claim 1 to 2 wherein the metal ions exchanged is selected from any potent transitional / non-transitional metal ions Cu2+, Cd2+, Zn2+. 4. An improved process for the preparation of metal complex - montmorillonite composite useful as deodorants substantially as herein described with reference to the examples.

Full Text

The present invention relates to an improved process for the preparation of metal complex -montmorillonite composite useful as deodorants. More particularly, the process of the present invention relates to pillaring of expandable layered clay like montmorillonite by stable cationic metal complex and then exchanging with potent transition metal cations responsible for arresting hydrogen sulfide, ammonia etc. from air. This invention is more particularly related to preparing efficient porous deodorants to purify indoor air/refrigerator or the like from polluting gases like hydrogen sulfide ammonia etc.
Hydrogen sulfide, ammonia and other similar gases, generated by decomposition of proteins and/or by other means pollute the air. Such polluting gases are harmful to animal as well as plant kingdom. Therefore, removal of such gases at least from indoor or refrigerator or from any closed room is essential or to bring the concentration well below the pollution level. Several types of deodorants have been developed to arrest such polluting gases from the air.
In general such deodorants are mostly prepared by supporting transition metal salts on supports like activated charcoal, zeolites, silica gel, diatomaceous earth, bentonite clay, fiber etc. Japanese Patent application No. 63-220872 (1988) discloses the preparation of deodorants effective against polluting gases generated from fish, meat, or sulfur compounds etc. which consists of fibrous supports like those of traditional Japanese made paper and ordinary paper, fabrics, glass fibre etc. including 5-40 wt. % (to the wt. of the support) of one or more of CaSO4, FeS04, ZnSO4 and MgSO4. Such deodorants are in general less effective in removing the odorous compounds from air. Another Japanese (Patent application No. 63-186656 (1988).... discloses preparation of deodorants for ammonia, amine, hydrogen sulfide, mercaptans; which comprises Zn compounds or Cu(II) compounds with different

anions supported on porous zeolite or activated charcoal etc. Zn/Cu ions form coordination complex with ammonia and amines or metal sulfide compounds CuS/ZnS with hydrogen sulfide, mercaptans or alkylsulfides. The active species responsible for arresting the polluting gases are less strongly anchored on the supports and also less uniformly distributed over the entire surface and hence are less effective for using as deodorants. Japanese Patent application No. 62-155935 of 1987 discloses the preparation of deodorant based on swellable mica layers. Alkali ion among the layers are substituted by metal ions like T14+, A13+, Zn2+ etc. through ion exchange to form substituted compounds. Solid acids is preparted among the layers by dehydrating or heating the substituted compounds. The deodorants are used to remove smell of H2S, NH3 and mercaptans. The action of such deodorants is due to neutralization of the basic polluting gases by the solid acid and adsorbed in the interlayers. Such deodorants exhibit very small interlayer gap and therefore may find limited use. In another invention (Japanese Patent application No. 63-249565 of 1988) the preparation of deodorants are described where layered smectite group minerals are loaded with metal ions like Cu2+, Co2+, Cd2+, Ag+ asnd Zn2+ or their hydroxide or oxide compounds. Thus for example Cu(N03)2 aqueous solution was blended with
laponite XIG (a synthetic smectite group minerals) and then settled to give a
precipitate, which was filtered, washed and dried at 80°C and pulverized to obtain a deodorant with light blue color. Such deodorant is claimed to be efficient in arresting H,S and mercaptan gas adsorption. This invention is based on expandable matrix i.e.
lamellar structure of clay consisting layers which upon hydration get separated and ultimately cause expansion as a whole. Normally, such expandable layered materials though effective as deodorants, the free access of the polluting gases like ammonia, hydrogen sulfide or bigger sized molecules etc. are restricted since the interlayer gap

is very small or filled with aqueous phase at room temperature. Therefore, use of lamellar support, if not pillared to increase the interlayer gap, show limitations of space for accommodating adsorbed species. Other inventions (Japanese Patent application No. 63-054935 of 1988 and US Patent No. 5108739 of 1992) disclose the preparation of white powder deodorant which consists of an aggregate of close bonding body grain of ZnO, TiO2 and H2O. The ratio of ZnO and TiO2 is in 1:9 - 9:1 or 3:7 - 7:3 by mol ratio. Preparation of such deodorants comprises mixing an alkaline solution and mixed aqueous solution containing water soluble titanium (like titanium sulphate, chloride, nitrate etc.) and water soluble zinc compounds (like zinc sulphate, chloride, etc.) to give solution with pH 6 - 11. A precipitate is formed at 40 - 60°C, which is separated from the mixed solution, and dried at 150-220°C. A white fine powder which consist of ZnO and Ti02 is obtained. The deodorant is stable up to 400°C. Such deodorants are useful for bad smell gas like H2S, NH3 etc. These type of deodorants exhibit low surface area and hence are not much effective.
The main objective of the present invention is to provide an improved process for the preparation of metal complex - montmorillonite composite useful as deodorants.
Accordingly, the present invention provides an improved process for the preparation of metal complex-montmorillonite composites useful as deodorants which comprises; treating purified bentonite clay with sodium salt to obtain sodium montmorillonite, partially exchanging (10 to 50% of the cation exchange capacity) the Na+ ions with stable three dimensional cationic metal complexes having formula [M(L-L)]n+ where M = Ni and L-L = 1,10-phenanthroline, 2,2'-bipyridine, exchanging the rest (50 to 90% of cation exchange capacity) Na+ ions with Mn+ cations where Mn+ = Cu++, Cd ++ by conventional methods as herein described to obtain the Mn+-[M(L-L)]n+ -montmorillonite composites, drying at temperature in the range of 50 to 250°C for a period 30 minutes to 8 hours, pulverizing by known methods to obtain metal complex

- montmorillonite composites, characterized in that in the steps, treating purified bentonite clay with sodium salt and exchanging the Na + ions with three dimensional cationic metal complex.
The oxidic compositions of the Bentonite clay is given below (Table 1)
Table 1, Chemical composition of Bentonite

(Table Removed)
In an embodiment of the present invention, the bulky cationic metal complex is selected from any octahedral or tetrahedral or the like three dimensional cationic metal complexes.
In another embodiment of the present invention, the requirement of the cationic metal complex may be only about 10% of the cationic exchange capacity of the bentonite clay.

In yet another embodiment of the present invention, the metal cations to be used are from transitional and / or non-transition metal groups.
Purification of Bentonite (Montmorillonite):
The above Bentonite powder was purified by standard gravity settling technique and the -2 µm fraction was collected in order to obtain the montmorillonite fraction. About 20 g of Bentonite was suspended in 1000 ml distilled water by stirring for half an hour and was set aside for about 24 hrs. The suspension up to 10 cm height from the top of the surface of the suspending liquid was collected for -2µ m particle size.
The mass was then dried above 50 C in air oven. This fraction of the clay was rich in montmorillonite.
Conversion into Na-montmorillonite:
The purified clay contains cations like Ca++ and Na+ in the interlayers as exchangeable form. As Na+ is readily exchangeable, the clay is converted into Na-montmorillonite form by treating with NaCl solution. About 2 g of dry purified clay was suspended into 100 ml of distilled water and to it 100 ml of 2 M NaCl solution was added and kept stirring for about 12 hrs. The mass was allowed to settle and the supernatant liquid was decanted of. The slurry was again treated with NaCl solution and stirred. This step was repeated for about 4 times. The excess NaCl was removed by washing with distilled water and finally dialysed till the conductivity of water is The dialysed Na-montmorillonite was identified by measuring the basal spacing (doo1) by XRD technique. Oriented film was prepared on glass slide by allowing about 1 ml suspension to dry at room temperature. The basal spacing of about 12 Å was

observed for air dried sample. The slide was then kept in a desiccator over ethylene glycol for about 12 hrs. The d001 value obtained at 16.5 A indicated the identification of montmorillonite clay.
Cation Exchange Capacity (CEC):
About 0.5 g of the clay was treated with 4 times of CEC(range 80-130 meq. / 100 g clay) of CaCl2 (alcoholic) solution and kept overnight under stirring condition.
The difference in the concentration of CaCl2 gave the amount of Ca++ exchanged. The value as determined for the clay was 114 meq. /100 g of clay.
Preparation of the Metal complexes :
The complexes (M(L-L)3]X where M = Ni, L-L = 1.10- phenanthroline 2,2'-bipyridine, X = S04 were prepared and crystallized by known methods. And the metal salts MX2 (M = Cu, Cd etc, X = Cl) used were of analytical grade.
Swelling/expandable clays like smectite group of clays particularly montmorillonite clay has been selected as supporting inorganic solid matrix because of its physico-chemical characteristics. Montmorillomte is composed of layered lattice structure and each sheet is composed of octahedral alumina sandwiched by two tetrahedral sheets of silica. The negative charge on the surface of these layers are, in general, developed by the isomorphous substitution of alumina in octahedral layer by lower valent cations like magnesium or iron. These negative charges are then counter
balanced by exchangeable cations like Na+ , Ca++ , Mg++ residing mostly in the interlayer space. These layered structures enable intercalation of other compounds of different characteristics between the sheets of the clay.

Water, having the solvation energy higher than the combination of van der Waals attraction between the clay layers and the electrostatic forces generated by the interlayer exchangeable cations both of which oppose interlayer expansion, expands
the layers. Upon heating at about 150 ºC, most of the interlayer water is lost and the layers of the clay approach closer to each other and leave very narrow interlayer space
and heating at about 250 - 300º C, the interlayer cations diffuses into the layer matrix and the layers are collapsed. The basal spacing i.e. the distance from the top of a layer to the top of the immediate layer, of Na-exchanged montmorillonite dried at 110 °C for 2 hrs., show a value of about 12 Å. This basal spacing for a fully collapsed matrix is about 9.6 A i.e. the layer thickness.
The cation exchange capacity (CEC) of such montmori- llonite clay ranges from 80 to 130 meq. / 100 g clay. Therefore, if the interlayer cations are exchanged with
bigger sized tree dimensional cationic metal complex like [Ni(phen/bipy)3]++ having a diameter about 7 Å (in C3 axis), the basal spacing obtained is about 17Å even after
heating at about 500° C. Thus, an expansion of the layers by about 7Å is possible by such pillaring metal complex and is dependent upon the dimension of the three dimensional species. Of course, pillaring by other species like hydroxy alumina or the likes are well known.
Therefore, Na-montmorillonite is subjected to partial (10-50% of the CEC)
exchange with bulky cationic metal complex [Ni(phen/bipy)3] ++ to give a
homogeneous intercalated metal complex-montmorillonite exhibiting about 17 Å basal spacing (d001). The intercalated product is further ion exchangedi.e. left out 50 -
.80 % cations (Na )are exchanged with multivalent cations Mn+ like Cu ++ , Cd ++ etc.
THE resulting Mm+ -[Ni(phen)3] ++ -montmoillonite still show the basal spacing value at
about 17 Å even after drying over 200° C. Such composite materials are very much potent in respect of developing Bronsted and Lewis acids. Bronsted acidity is developed due to the exchanged metal cations which polarize interlayer water molecules. Partial dehydration increases the acidity, but the acidity of Na+ ion is not high. When the interlayer water is lost due to heating at higher temperature, the metal ion exchanged montmorillonite behaves as Lewis acids. These types of acidity of the solid composites are very useful as acid catalysts in organic synthesis. In the present investigation, the acidic characteristics of the composites will be primarily utilized for neutralizing bases like amines etc. from the air borne gases.
Again, the cations remain in the interlayer space can react with H2S or other sulfur
containing compounds and retain strongly into the interlayer spacing. Besides, some of the cations will form coordination complexes with the polluting gases like NH3
present in air under suitable condition. Therefore, partially intercalated (pillared) with cationic metal complex-metal ion exchanged montmorillonite can offer considerably high interlamellar space for free access of smaller to bigger molecules having dimension below 7Å and thus may prove to be an effective deodorants for a variety of polluting gases based on sulfur, nitrogen or the likes.
The following examples are given by way of illustrations of the present invention and should not be construed to limit the scope of the invention.
Example 1 :
About 0.5 g of -2 µm fraction of dried Na-montmorillonite clay was dispersed in about 200 ml of distilled water under constant stirring and then mixed thoroughly under ultrasonic vibration for about 10 min. To this homogeneous suspension, a solution (2.5 ml containing 0.039 g of [Ni(phen)3]SO4) was added and stirred for

about 30 min. The mass was centrifuged (rpm 12000) for about 15 min. and then washed with distilled water. The mass collected was again dispersed in about 200 ml distilled water under ultrasonic condition for about 10 min. and about 0.038 g of CuCl2 was added and stirred for about 24 hrs and centrifuged to remove the
supernatant liquid. This step was repeated for about three times. Finally, the mass was
washed with distilled water and dried at 50 °C for 8 hours or at 250°C for 30 minutes. The color of the product was light bluish and kept in air tight bottle.
Upon contacted with H2S gas, the composite turns into a blackish solid due to forming a CuS compound.
Again, upon contacted fresh composites with NH3 gas, it turns into a bluish
colored solid which was due to the formation of [Cu(NH3)4]++ complex into the interlamellar spacing.
Example 2 :
About 0.5 g of -2µm fraction of dried Na-montmorillonite clay was dispersed in about 200 ml of distilled water under constant stirring and then mixed thoroughly under ultrasonic vibration for about 10 min. To this homogeneous suspension, a solution (2.5 ml containing 0.039 g of [Ni(phen)3]SO4) was added and stirred for
about 30 min. The mass was centrifuged (rpm 12000) for about 15 min. and then washed with distilled water. The mass collected was again dispersed in about 200 ml distilled water under ultrasonic condition for about 10 min. and about 0.052 g of CdCl2 in 2 ml water was added and stirred for about 24 hrs and centrifuged to remove
the supernatant liquid. This step was repeated. Finally, the mass was washed with

distilled water and dried at 50º C for 8 hours or at 250º C for 30 minutes. The product was then kept in air tight bottle.
Upon contacted with H2S gas, the composite turns into a yellowish solid due to formation of CdS compound.
Example 3 :
About 0.5 g of -2 µm fraction of dried Na-montmorillonite clay was dispersed in about 200 ml of distilled water under constant stirring and then mixed thoroughly under ultrasonic vibration for about 10 min. To this homogeneous suspension, a solution (2.5 ml containing 0.099 g of [Ni(phen)3]SO4) was added and stirred for about 30 min. The mass was centrifuged (rpm 12000) for about 15 min. and then washed with distilled water. The mass collected was again dispersed in about 200 ml distilled water under ultrasonic condition for about 10 min. and about 0.024 g of CuCl2 was added and stirred for about 24 hrs and centrifuged to remove the
supernatant liquid. This step was repeated for about three times. Finally, the mass was
washed with distilled water and dried at temperature 50 ºC for 8 hours or at 250º C for . 30 min. The color of the product was light bluish and kept in air tight bottle.
Upon contacted with H2S gas, the composite turns into a blackish solid due to
forming a CuS compound.
Again, upon contacted fresh composites with NH3 gas, it turns into a bluish
colored solid which was due to the formation of [Cu(NH3)4]++ complex into the
interlamellar spacing.

Example 4 :
About 0.5 g of -2 µm fraction of dried Na-montmorillonite clay was dispersed in about 200 ml of distilled water under constant stirring and then mixed thoroughly under ultrasonic vibration for about 10 min. To this homogeneous suspension, a olution (2.5 ml containing 0.099 g of [Ni(phen)3]SO4) was added and stirred for about
30 min. The mass was centrifuged (rpm 12000) for about 15 min. and then washed with distilled water. The mass collected was again dispersed in about 200 ml distilled water under ultrasonic condition for about 10 min. and about 0.032 g of CdCl2 was
added and stirred for about 24 hrs and centrifuged to remove the supernatant liquid. This step was repeated for about three times. Finally, the mass was washed with
distilled water and dried at temperature 50°C for about 8 or at 250°C for 30 min. The product was kept in air tight bottle.
Upon contacted with H.S gas, the composite turns into a yellowish solid due to formation of CdS compound.
Example 5:
About 0.5 g of -2µ m fraction of dried Na-montmorillonite clay was dispersed in about 200 ml of distilled water under constant stirring and then mixed thoroughly under ultrasonic vibration for about 10 min. To this homogeneous suspension, a solution (2.5 ml containing 0.035 g of [Ni(bipy)3]SO4) was added and stirred for
about 30 min. The mass was centrifuged (rpm 12000) for about 15 min. and then washed with distilled water. The mass collected was again dispersed in about 200 ml distilled water under ultrasonic condition for about 10 min. and about 0.038 g of CuCl2 was added and stirred for about 24 hrs. and centrifuged to remove the

supernatant liquid. This step was repeated for about three times. Finally, the mass
was washed with distilled water and dried at temperature 50 ºC for about 8 hours or
at 250 ºC for 30 min. The color of the product was light bluish and kept in air tight bottle.
Upon contacted with H2S gas, the composite turns into a blackish solid due to
formation of CuS compound.
Again, upon contacted with NH3 gas, the composite turns into a bluish colored
solid which was due to the formation of [Cu(NH3)4]++ complex into the interlamellar
spacing.
Example 6 :
About 0.5 g of -2 µm fraction of dried Na-montmorillonite clay was dispersed in about 200 ml of distilled water under constant stirring and then mixed thoroughly under ultrasonic vibration for about 10 min. To this homogeneous suspension, a solution (2.5 ml containing 0.035 g of [Ni(bipy)3]SO4) was added and stirred for
about 30 min. The mass was centrifuged (rpm 12000) for about 15 min. and then washed with distilled water. The mass collected was again dispersed in about 200 ml distilled water under ultrasonic condition for about 10 min. and about 0.052 g of CdCl2 in 2 ml water was added and stirred for about 24 hrs and centrifuged to remove
the supernatant liquid. This step was repeated. Finally, the mass was washed with
distilled water and dried at temperature 50º C for about 8 hours or at 250 ºC for 30 min. The product was kept in air tight bottle.
Upon contacted with H2S gas, the composite turns into a yellowish solid due to
formation of CdS compound.

Example 7 :
About 0.5 g of-2 µm fraction of dried Na-montmorillonite clay was dispersed in about 200 ml of distilled water under constant stirring and then mixed thoroughly under ultrasonic vibration for about 10 min. To this homogeneous suspension, a solution (2.5 ml containing 0.088 g of [Ni(bipy)3]SO4) was added and stirred for
about 30 min. The mass was centrifuged (rpm 12000) for about 15 min. and then washed with distilled water. The mass collected was again dispersed in about 200 ml distilled water under ultrasonic condition for about 10 min. and about 0.024 g of CuCl2 was added and stirred for about 24 hrs and centrifuged to remove the
supernatant liquid. This step was repeated for about three times. Finally, the mass was washed with distilled water and dried at temperature 50 C for about 8 hours or at 250
ºC for 30 min. The color of the product was light bluish and kept in air tight bottle. Upon contacted with H2S gas, the composite turns into a blackish solid due to
formation of CuS compound.
Again, upon contacted with NH3 gas, the composite turns into a bluish colored
solid which was due to the formation of [Cu(NH3)]4++ complex into the interlamellar spacing.
Example 8 :
About 0.5 g of -2 µm fraction of dried Na-montmorillonite clay was dispersed in about 200 ml of distilled water under constant stirring and then mixed thoroughly under ultrasonic vibration for about 10 min. To this homogeneous suspension, a solution (2.5 ml containing 0.088 g of [Ni(bipy)3]SO4) was added and stirred for
about 30 min. The mass was centrifuged (rpm 12000) for about 15 min. and then

washed with distilled water. The mass collected was again dispersed in about 200 ml distilled water under ultrasonic condition for about 10 min. and about 0.032 g of CdCl2 was added and stirred for about 24 hrs and centrifuged to remove the
supernatant liquid. This step was repeated for about three times. Finally, the mass was
washed with distilled water and dried at temperature 50º C for about 8 hours or at 250
ºC for 30 min. The product was kept in air tight bottle. Upon contacted with H2S gas, the composite turns into a yellowish solid due to
formation of CdS compound.
The main advantages of the present invention are
1. The products can arrest large three dimensional odorous / non-odorous molecules.
2. The products can provide sufficient space (at least 7-8 A gap between the layers)
for accommodating coordination compounds formed in-situ by the reaction between
the metal cations and the coordinating gaseous molecules.
3. The product can provide higher surface area for efficient adsorption.

4. The products can provide desired interlamellar space-gap (tailor-made) for
adsorbing selective polluting gases.
5. The products can be utilized for other purposes particularly for suitable catalytic
reactions.

We Claim:
1. An improved process for the preparation of metal complex-montmorillonite
composites useful as deodorants which comprises; treating purified bentonite clay
with sodium salt to obtain sodium montmorillonite, partially exchanging (10 to
50% of the cation exchange capacity) the Na+ ions with stable three dimensional
cationic metal complexes having formula [M(L-L)]n+ where M = Ni and L-L =
1,10-phenanthroline, 2,2'-bipyridine, exchanging the rest (50 to 90% of cation
exchange capacity) Na+ ions with Mn+ cations where Mn+ = Cu++, Cd ++ by
conventional methods as herein described to obtain the Mn+-[M(L-L)]n+ -
montmorillonite composites, drying at temperature in the range of 50 to 250°C for
a period 30 minutes to 8 hours, pulverizing by known methods to obtain metal
complex - montmorillonite composites, characterized in that in the steps, treating
purified bentonite clay with sodium salt and exchanging the Na + ions with three
dimensioned cationic metal complex.
2. An improved process as claimed in claim 1 wherein the bulky cationic metal
complex is selected from hexagonal or tetrahedral cationic or any three
dimensional cationic metal complex.
3. An improved process as claimed in claim 1 to 2 wherein the metal ions exchanged
is selected from any potent transitional / non-transitional metal ions Cu2+, Cd2+,
Zn2+.
4. An improved process for the preparation of metal complex - montmorillonite
composite useful as deodorants substantially as herein described with reference to
the examples.

Documents:

1489-del-1999-abstract.pdf

1489-del-1999-claims.pdf

1489-del-1999-correspondence-others.pdf

1489-del-1999-correspondence-po.pdf

1489-del-1999-description (complete).pdf

1489-del-1999-form-1.pdf

1489-del-1999-form-19.pdf

1489-del-1999-form-2.pdf

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Patent Number

215818

Indian Patent Application Number

1489/DEL/1999

PG Journal Number

12/2008

Publication Date

21-Mar-2008

Grant Date

04-Mar-2008

Date of Filing

18-Nov-1999

Name of Patentee

COUNCIL OF SCIENTIFIC AND INDUSTRIAL RESEARCH

Applicant Address

RAFI MARG, NEW DELHI-110 001, INDIA.

Inventors:

#	Inventor's Name	Inventor's Address
1	DIPAK KUMAR DUTTA	REGIONAL RESEARCH LABORATORY, JORHAT-785006, ASSAM, INDIA.
2	MOUSHUMI BORA	REGIONAL RESEARCH LABORATORY, JORHAT-785006, ASSAM, INDIA.

PCT International Classification Number

A41B 013/02

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA