Description:FIELD
The present disclosure relates to a process for the preparation of hydrophobic carbon black.
DEFINITION
As used in the present disclosure, the following term is generally intended to have the meaning as set forth below, except to the extent that the context in which it is used indicates otherwise.
Reflux: The term “reflux” refers to a technique that involves the evaporation and condensation of vapors and the return of the condensate to the vessel from which it originated.
BACKGROUND
The background information herein below relates to the present disclosure but is not necessarily prior art.
Carbon black is one of the most stable chemical products which is widely used as reinforced filler for polymers. The incorporation of the filler into polymer enhances the mechanical properties of the composite polymer and decreases the cost of the product. The properties of the composite polymer depend mainly on how well the fillers disperse within the polymer matrix and also on the interaction of the polymer and the filler. In addition, the fillers can impart new functional properties such as flame retardancy, conductivity and the like to the polymer which is not possessed by the polymer matrix alone. The properties of the filler such as particle size, surface area, aggregate structure, surface activity and the like, mostly control the interaction of the filler with the polymer matrix and also the dispersion in the polymer matrix. It is known that increase in the surface area of filler (e.g. carbon filler) increases tensile strength, hardness and abrasion resistance of the final polymer composite thereby decreasing the loading amount of the filler.
Conventional processes for the production of carbon black includes furnace process, channel process and acetylene process and the like. These processes of manufacturing of the carbon black are commonly controlled by vapour-phase pyrolysis and partial combustion of hydrocarbons, wherein typical processing temperatures for manufacturing the carbon black are high in the range of 800 °C to 1200 °C. Further, the hydrophobic carbon black can be obtained by halogenation of the carbon black, preferably fluorination of carbon black is known to be performed to achieve high degree of hydrophobicity. However, the process of fluorination is cumbersome and tedious.
Further, the preparation of the hydrophobic carbon black from the industrial waste is also known in the art. The industrial waste includes the chlorinated waste generated from the vinyl chloride monomer plant. In vinyl chloride monomer plants, chlorinated hydrocarbon mixtures are generated as a waste due to uncontrolled radical chlorination of ethylene. High temperature incineration, i.e., at a temperature of 1450 °C, of the chlorinated hydrocarbon mixture converts to carbon dioxide and hydrochloric acid is the only known option globally. However, the incineration process required high energy and is responsible for environmental pollution due to carbon dioxide emission. The chlorinated waste can be used for synthesis of copolymer with sulfur or alkali sulfide. However, no valuable commercial utilization is known so far for such wastes.
Therefore, there is felt a need to develop a process for the preparation of hydrophobic carbon black that overcomes the above-mentioned limitations or provide at least a useful alternative.
OBJECTS
Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows.
It is an object of the present disclosure to ameliorate one or more problems of the background or to at least provide a useful alternative.
An object of the present disclosure is to provide a process for the preparation of hydrophobic carbon black.
Another object of the present disclosure is to provide a process for the preparation of hydrophobic carbon black from an industrial waste.
Still another object of the present disclosure is to provide an efficient and environment friendly process for the preparation of hydrophobic carbon black.
Yet another object of the present disclosure is to provide a process for the preparation of hydrophobic carbon black having a high surface area.
Other objects and advantages of the present disclosure will be more apparent from the following description, which is not intended to limit the scope of the present disclosure.
SUMMARY
The present disclosure relates to a process for the preparation of hydrophobic carbon black. The process comprising (i) charging a predetermined amount of a feed in a reactor followed by adding a predetermined amount of at least one catalyst at a temperature in the range of 20 oC to 50 oC to obtain a mixture. (ii) The mixture is heated to a first predetermined temperature for a first predetermined time period with simultaneous refluxing of compounds having low boiling point from the feed at a second predetermined temperature for a second predetermined time period to obtain a reaction mass. (iii) The temperature of the reaction mass is raised to a third predetermined temperature for a third predetermined time period for removing un-reacted chlorinated compounds from the reaction mass to obtain a solid mass. (iv) The solid mass is washed by using at least one solvent followed by washing with hot water and filtered to obtain solids and drying the solids at a fourth predetermined temperature for a fourth predetermined time period to obtain the hydrophobic carbon black.
In accordance with the embodiments of the present disclosure, the feed is at least one selected from a first feed and a second feed.
The first feed is a chlorinated hydrocarbon waste having predetermined concentrations of compounds having low boiling point and compounds having high boiling point.
In an embodiment, the first feed is a chlorinated hydrocarbon waste comprising compounds having low boiling point and compounds having high boiling point,
wherein the compounds having low boiling point in the first feed are selected from
• 30 mass% to 40 mass% of 1, 2 dichloroethane (EDC),
• 10 mass% to 15 mass% of 1,1,2 trichloroethane (TCA), and
• 4 mass% to 6 mass% of 1,1,2,2-tetrachloroethane,
wherein the compounds having high boiling point in the first feed are selected from
• 1 mass% to 3.0 mass% of pentachloroethane (PCE), and
• 35 mass% to 45 mass% of chlorinated hydrocarbons having boiling point greater than 200 oC.
The second feed is a chlorinated hydrocarbon waste having predetermined concentrations of compounds having low boiling point and compounds having high boiling point.
In another embodiment, the second feed is a chlorinated hydrocarbon waste comprises compounds having low boiling point and compounds having high boiling point, wherein the compounds having low boiling point in the second feed are selected from
• 5 mass% to 10 mass% of 1, 2 dichloroethane (EDC),
• 45 mass% to 50 mass% of 1,1,2 trichloroethane (TCA), and 1 mass% to 2 mass% of 1,1,2,2-tetrachloroethane, and
wherein the compounds having high boiling point in the second feed are selected from
• 0.05 mass% to 0.5 mass% of pentachloroethane (PCE),
• 2 mass% to 3 mass% of hexachloroethane and 40 mass% to 50 mass% of chlorinated hydrocarbons having boiling point greater than 200 oC.
In accordance with the embodiments of the present disclosure, the compounds having low boiling point have a boiling temperature in the range of 60 oC to 150 oC.
In accordance with the embodiments of the present disclosure, the compounds having low boiling point are present in the amount in the range of 1 mass% to 70 mass% with respect to the total mass of the feed.
In accordance with the embodiments of the present disclosure, acid fumes liberated during the reflux and removal of unreacted chlorinated compounds are trapped in a scrubber.
In accordance with the embodiments of the present disclosure, the predetermined amount of the feed is in the range of 96 mass% to 99 mass% with respect to the total mass of the mixture.
In accordance with the embodiments of the present disclosure, the predetermined amount of the catalyst is in the range of 1 mass% to 4 mass% with respect to the total mass of the mixture.
In accordance with the embodiments of the present disclosure, the first predetermined temperature is in the range of 125 oC to 160 oC.
In accordance with the embodiments of the present disclosure, the first predetermined time period is in the range of 1 hour to 5 hours.
In accordance with the embodiments of the present disclosure, the second predetermined temperature is in the range of 75 oC to 160 oC.
In accordance with the embodiments of the present disclosure, the second predetermined time period is in the range of 3 hours to 10 hours.
In accordance with the embodiments of the present disclosure, the third predetermined temperature is in the range of 200 oC to 250 oC.
In accordance with the embodiments of the present disclosure, the third predetermined time period is in the range of 2 hours to 6 hours.
In accordance with the embodiments of the present disclosure, the fourth predetermined temperature is in the range of 100 oC to 140 oC.
In accordance with the embodiments of the present disclosure, the fourth predetermined time period is in the range of 2 hours to 6 hours.
In accordance with the embodiments of the present disclosure, the at least one catalyst is a Lewis acid catalyst selected from the group consisting of AlCl3, ZnCl2, BF3, and SnCl4.
In accordance with the embodiments of the present disclosure, the hydrophobic carbon black is characterized by having a water contact angle in the range of 130º to 170º; a chlorine content in the range of 15 mass% to 30 mass%; and spherical aggregates having a particle size of less than 750 µm, a surface area in the range of 450 m2/g to 600 m2/g; a pore volume in the range of 0.20 m2/g to 0.40 m2/g, and a pore diameter in the range of 2 nm to 5 nm.
In accordance with the embodiments of the present disclosure, the hydrophobic carbon black is characterized by having the water contact angle in the range of 135o to 165o, the chlorine content in the range of 15 mass% to 25 mass%, and the spherical aggregates having the particle size of less than 390 µm, the surface area in the range of 490 m2/g to 565 m2/g, the pore volume in the range of 0.25 m2/g to 0.35 m2/g, and the pore diameter in the range of 2.5 nm to 4.0 nm.
In accordance with an embodiment, the present disclosure provides hydrophobic carbon black prepared by using the process of the present disclosure. The hydrophobic carbon black is characterized by having a water contact angle in the range of 130 o to 170 º, a chlorine content in the range of 15 mass% to 30 mass%, and are spherical aggregates having a particle size of less than 750 µm, a surface area in the range of 450 m2/g to 600 m2/g, a pore volume in the range of 0.1 m2/g to 0.5 m2/g, and a pore diameter in the range 2 nm to 5 nm.
In accordance with another embodiment of the present disclosure, the hydrophobic carbon black is characterized by having the water contact angle in the range of 135o to 165o, the chlorine content in the range of 15 mass% to 25 mass%, and the spherical aggregates having the particle size of less than 390 µm, the surface area in the range of 490 m2/g to 565 m2/g, the pore volume in the range of 0.25 m2/g to 0.35 m2/g, and the pore diameter in the range of 2.5 nm to 4.0 nm.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
The present disclosure will now be described with the help of the accompanying drawing, in which:
Fig. 1 illustrates Scheme 1, a plausible pathway of carbon black formation in accordance with the present disclosure;
Fig. 2(a) illustrates a process flow diagram for carbon black formation by re-circulation (reflux-condensation) of the compounds having low boiling point in accordance with example 1 of the present disclosure, wherein I represent starting of reaction setup with circulation of compounds having low boiling point; II represents initiation of carbon formation; III represents dense and dispersed carbon black formation; and IV represents removal of compounds having low boiling point by heating and leaving the carbon black with high surface area;
Fig. 2(b) illustrates a process flow diagram for carbon black formation without re-circulation (reflux-condensation) of the compounds having low boiling point in accordance with example 6 of the present disclosure, wherein I represent starting of reaction set up; and II represents carbon black formation along with removal of compounds having low boiling point through heating and leaving the carbon black less dispersed and with less surface area;
Fig. 3 illustrates scanning electron microscopy (SEM) images of carbon black obtained from chlorinated waste type A feed in accordance with example 1 of the present disclosure; wherein (a) represent the SEM image of the carbon black of example 1 under a scale of 200 µm; (b) represents the SEM image of the carbon black of example 1 under a scale of 50 µm; (c) represents the SEM image of the carbon black of example 1 under a scale of 10 µm; and (d) represents the SEM image of the carbon black of example 1 under a scale of 5 µm;
Fig. 4 illustrates scanning electron microscopy (SEM) images of carbon black obtained from chlorinated waste type A feed in accordance with example 2 of the present disclosure; wherein (a) represent the SEM image of the carbon black of example 2 under a scale of 200 µm; (b) represents the SEM image of the carbon black of example 2 under a scale of 50 µm; (c) represents the SEM image of the carbon black of example 2 under a scale of 10 µm; and (d) represents the SEM image of the carbon black of example 2 under a scale of 5 µm; and
Fig. 5 illustrates Fourier transform infrared (FTIR) spectra of the carbon black obtained by using the process in accordance with the present disclosure; wherein (a) represents FTIR spectra of the carbon black obtained by using the process of example 1; (b) represents FTIR spectra of the carbon black obtained by using the process of example 2; (c) represents FTIR spectra of the carbon black obtained by using the process of example 5.
DETAILED DESCRIPTION
The present disclosure relates to a process for the preparation of hydrophobic carbon black.
Embodiments, of the present disclosure, will now be described with reference to the accompanying drawing.
Embodiments are provided so as to thoroughly and fully convey the scope of the present disclosure to the person skilled in the art. Numerous details, are set forth, relating to specific components, and methods, to provide a complete understanding of embodiments of the present disclosure. It will be apparent to the person skilled in the art that the details provided in the embodiments should not be construed to limit the scope of the present disclosure. In some embodiments, well-known processes, well-known apparatus structures, and well-known techniques are not described in detail.
The terminology used, in the present disclosure, is only for the purpose of explaining a particular embodiment and such terminology shall not be considered to limit the scope of the present disclosure. As used in the present disclosure, the forms "a,” "an," and "the" may be intended to include the plural forms as well, unless the context clearly suggests otherwise. The terms "comprises," "comprising," “including,” and “having,” are open ended transitional phrases and therefore specify the presence of stated features, elements, modules, units and/or components, but do not forbid the presence or addition of one or more other features, elements, components, and/or groups thereof.
As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed elements.
The terms first, second, third, etc., should not be construed to limit the scope of the present disclosure as the aforementioned terms may be only used to distinguish one element, component, region, layer or section from another component, region, layer or section. Terms such as first, second, third etc., when used herein do not imply a specific sequence or order unless clearly suggested by the present disclosure.
Carbon black is one of the most stable chemical products which is widely used as reinforced filler for polymers. The incorporation of the filler into polymer enhances the mechanical properties of the composite polymer and decreases the cost of the product. The properties of the composite polymer depend mainly on how well the fillers disperse within the polymer matrix and also on the interaction of the polymer and the filler. In addition, the fillers can impart new functional properties such as flame retardancy, conductivity and the like to the polymer which is not possessed by the polymer matrix alone. The properties of the filler such as particle size, surface area, aggregate structure, surface activity and the like, mostly control the interaction of the filler with the polymer matrix and also the dispersion in the polymer matrix. It is known that increase in the surface area of filler (e.g. carbon filler) increases tensile strength, hardness and abrasion resistance of the final polymer composite thereby decreasing the loading amount of the filler.
Conventional processes for the production of carbon black includes furnace process, channel process and acetylene process and the like. These processes of manufacturing of the carbon black are commonly controlled by vapour-phase pyrolysis and partial combustion of hydrocarbons, wherein typical processing temperatures for manufacturing the carbon black are high in the range of 800 °C to 1200 °C. Further, the hydrophobic carbon black can be obtained by halogenation of the carbon black, preferably fluorination of carbon black is known to be performed to achieve high degree of hydrophobicity. However, the process of fluorination is cumbersome and tedious.
Further, the preparation of the hydrophobic carbon black from the industrial waste is also known in the art. The industrial waste includes the chlorinated waste generated from the vinyl chloride monomer plant. In vinyl chloride monomer plants, chlorinated hydrocarbon mixtures are generated as a waste due to uncontrolled radical chlorination of ethylene. High temperature incineration, i.e., at a temperature of 1450 °C, of the chlorinated hydrocarbon mixture converts to carbon dioxide and hydrochloric acid is the only known option globally. However, the incineration process required high energy and is responsible for environmental pollution due to carbon dioxide emission. The chlorinated waste can be used for synthesis of copolymer with sulfur or alkali sulfide. However, no valuable commercial utilization is known so far for such wastes.
The present disclosure provides a process for the preparation of hydrophobic carbon black. The process comprising charging a predetermined amount of a feed in a reactor followed by adding a predetermined amount of at least one catalyst at a temperature in the range of 20 oC to 50 oC to obtain a mixture. The mixture is heated to a first predetermined temperature for a first predetermined time period with simultaneous refluxing of compounds having low boiling point from the feed at a second predetermined temperature for a second predetermined time period to obtain a reaction mass. The temperature of the reaction mass is raised to a third predetermined temperature for a third predetermined time period for removing un-reacted chlorinated compounds from the reaction mass to obtain a solid mass. The solid mass is washed by using at least one solvent followed by washing with hot water and filtered to obtain solids and drying the solids at a fourth predetermined temperature for a fourth predetermined time period to obtain the hydrophobic carbon black.
The process is described in detail.
Initially, a predetermined amount of a feed is charged in a reactor followed by adding a predetermined amount of at least one catalyst at a temperature in the range of 20 oC to 50 oC to obtain a mixture.
In accordance with the embodiments of the present disclosure, the feed is at least one selected from a first feed and a second feed. The first feed is chlorinated hydrocarbon waste having predetermined concentrations of compounds having low boiling point and compounds having high boiling point. The second feed is chlorinated hydrocarbon waste having predetermined concentrations of compounds having low boiling point and compounds having high boiling point.
In accordance with the present disclosure, the feed is the waste generated from vinyl chloride monomer plant which consists of mixture of chlorinated hydrocarbons.
In accordance with the embodiments of the present disclosure, the compounds having low boiling point have a boiling temperature in the range of 60 oC to 150 oC. In an exemplary embodiment, the compounds having low boiling point is 1,2-Dichloroethane (EDC) having a boiling temperature of 83 oC. In another exemplary embodiment, the compounds having low boiling point is 1,1,2-trichloroethane (TCA) having a boiling temperature of 114 oC. In still another exemplary embodiment, the compounds having low boiling point is 1,1,2,2-tetrachloroethane (TeCA) having a boiling temperature of 147 oC.
In accordance with the embodiments of the present disclosure, the compounds having low boiling point are in the amount in the range of 1 mass% to 70 mass% with respect to the total mass of the feed. In an embodiment, 1,2-Dichloroethane (EDC) is in the range of 34 mass% to 40 mass% with respect to the total mass of the feed. In another embodiment, 1,2-Dichloroethane (EDC) is in the range of 6 mass% to 8 mass% with respect to the total mass of the feed. In still another embodiment, 1,1,2-trichloroethane (TCA) is in the range of 45 mass% to 50 mass% with respect to the total mass of the feed. In yet another embodiment, 1,1,2,2-tetrachloroethane (TeCA) is in the range of 1 mass% to 2 mass% with respect to the total mass of the feed. In yet another embodiment, the compounds having low boiling point are in the amount in the range of 48 mass% to 60 mass% with respect to the total mass of the feed.
The effect of the compounds having low boiling point present in the chlorinated waste feed is to produce carbon black of different morphologies. When the compounds having low boiling point present in the chlorinated waste feed is higher, the surface area of the hydrophobic carbon black so formed is also high.
In an embodiment, the first feed is a chlorinated hydrocarbon waste comprises compounds having low boiling point and compounds having high boiling point, wherein the compounds having low boiling point are selected from 30 mass% to 40 mass% of 1, 2 dichloroethane (EDC), 10 mass% to 15 mass% of 1,1,2 trichloroethane (TCA), and 4 mass% to 6 mass% of 1,1,2,2-tetrachloroethane; wherein the compounds having high boiling point are selected from 1 mass% to 3.0 mass% of pentachloroethane (PCE), and 35 mass% to 45 mass% of chlorinated hydrocarbons having boiling point greater than 200 oC.
In another embodiment, the second feed is a chlorinated hydrocarbon waste comprises compounds having low boiling point and compounds having high boiling point, wherein the compounds having low boiling point are selected from 5 mass% to 10 mass% of 1, 2 dichloroethane (EDC), 45 mass% to 50 mass% of 1,1,2 trichloroethane (TCA), and 1 mass% to 2 mass% of 1,1,2,2-tetrachloroethane, and wherein the compounds having high boiling point are selected from 0.05 mass% to 0.5 mass% of pentachloroethane (PCE), 2 mass% to 3 mass% of hexachloroethane and 40 mass% to 50 mass% of chlorinated hydrocarbons having boiling point greater than 200 oC.
In accordance with the embodiments of the present disclosure, the predetermined amount of the feed is in the range of 96 mass% to 99 mass% with respect to the total mass of the mixture. In the exemplary embodiments, the predetermined amount of the feed is 98 mass% with respect to the total mass of the mixture.
In accordance with the embodiments of the present disclosure, the at least one catalyst is a Lewis acid catalyst selected from the group consisting of AlCl3, ZnCl2, BF3, and SnCl4. In an exemplary embodiment, the at least one catalyst is anhydrous AlCl3.
In accordance with the embodiments of the present disclosure, the predetermined amount of the at least one catalyst is in the range of 1 mass% to 4 mass% with respect to the total mass of the mixture. In an exemplary embodiment, the predetermined amount of the at least one catalyst is 2 mass% with respect to the total mass of the mixture.
In a second step, the mixture is heated to a first predetermined temperature for a first predetermined time period with simultaneous refluxing of compounds having low boiling point from the feed at a second predetermined temperature for a second predetermined time period to obtain a reaction mass.
Heating the feed in the presence of a catalyst to a first predetermined temperature initiates the dehydrochlorination of the chlorinated hydrocarbon feed.
In accordance with the embodiments of the present disclosure, the first predetermined temperature is in the range of 125 oC to 160 oC. In an exemplary embodiment, the first predetermined temperature is 150 oC.
In accordance with the embodiments of the present disclosure, the first predetermined time period is in the range of 1 hour to 5 hours. In another exemplary embodiment, the first predetermined time period is 2 hours 30 minutes.
In accordance with the embodiments of the present disclosure, the second predetermined temperature is in the range of 75 oC to 160 oC. In an exemplary embodiment, the second predetermined temperature is 85 oC. At the second predetermined temperature, the compounds having low boiling point start to reflux, and the refluxing is continued till the temperature reaches the first predetermined temperature.
In accordance with the embodiments of the present disclosure, the second predetermined time period is in the range of 3 hours to 10 hours. In an exemplary embodiment, the second predetermined time period is 6 hours.
In a third step, the temperature of the reaction mass is raised to a third predetermined temperature for a third predetermined time period for removing unreacted chlorinated compounds from the reaction mass to obtain a solid mass.
In accordance with the embodiments of the present disclosure, the third predetermined temperature is in the range of 200 oC to 250 oC. In an exemplary embodiment, the third predetermined temperature is 220 oC.
In accordance with the embodiments of the present disclosure, the third predetermined time period is in the range of 2 hours to 6 hours. In an exemplary embodiment, the third predetermined time period is 4 hours.
In accordance with the embodiments of the present disclosure, the compounds having low boiling point are firstly refluxed and collected at the first predetermined temperature by distillation before raising the temperature of the reaction mass to the third predetermined temperature. The collected compounds having low boiling point are reused.
In a fourth step, the solid mass is washed by using at least one solvent followed by washing with hot water and filtered to obtain solids and drying the solids at a fourth predetermined temperature for a fourth predetermined time period to obtain the hydrophobic carbon black.
In accordance with the embodiments of the present disclosure, the at least one solvent is selected from the group consisting of dichloromethane, dichloroethane, and trichloromethane. In an exemplary embodiment, the solvent is dichloromethane.
In accordance with the embodiments of the present disclosure, the fourth predetermined temperature is in the range of 100 oC to 140 oC.
In accordance with the embodiments of the present disclosure, the fourth predetermined time period is in the range of 2 hours to 6 hours.
In an exemplary embodiment, the fourth predetermined temperature is 120 oC; and the fourth predetermined time period is 4 hours.
In accordance with the embodiments of the present disclosure, acid fumes liberated during refluxing in the second step and removal of unreacted chlorinated compounds in the third step are trapped in a scrubber.
In accordance with the embodiments of the present disclosure, the hydrophobic carbon black is characterized by having a water contact angle in the range of 130 o to 170 º, a chlorine content in the range of 15 mass% to 30 mass%, and are spherical aggregates having a particle size of less than 750 µm, a surface area in the range of 450 m2/g to 600 m2/g, a pore volume in the range of 0.1 m2/g to 0.5 m2/g and a pore diameter in the range 2 nm to 5 nm. The particle size of the spherical aggregates can be further reduced by milling process.
In accordance with the embodiments of the present disclosure, the hydrophobic carbon black is characterized by having the water contact angle in the range of 135o to 165o, the chlorine content in the range of 15 mass% to 25 mass%, and the spherical aggregates having the particle size of less than 390 µm, the surface area in the range of 490 m2/g to 565 m2/g, the pore volume in the range of 0.25 m2/g to 0.35 m2/g and the pore diameter in the range of 2.5 nm to 4.0 nm.
In an exemplary embodiment, the hydrophobic carbon black is characterized by having the water contact angle of 153º, the chlorine content of 23 mass%, and the spherical aggregates have an average particle size of 384 µm, the surface area of 560 m2/g, the pore volume of 0.32 m2/g, and the pore diameter of 3.6 nm.
In another exemplary embodiment, the hydrophobic carbon black is characterized by having the water contact angle of 140º, the chlorine content of 23 mass%, and the spherical aggregates have an average particle size of 384 µm, the surface area of 497 m2/g, the pore volume of 0.25 m2/g, and the pore diameter of 2.74 nm.
In still another exemplary embodiment, the hydrophobic carbon black has water contact angle of 160o.
In accordance with an embodiment, the present disclosure provides hydrophobic carbon black prepared by using the process of the present disclosure. The hydrophobic carbon black is characterized by having a water contact angle in the range of 130o to 170º, a chlorine content in the range of 15 mass% to 30 mass%, and are spherical aggregates having a particle size of less than 750 µm, a surface area in the range of 450 m2/g to 600 m2/g, a pore volume in the range of 0.1 m2/g to 0.5 m2/g and a pore diameter in the range 2 nm to 5 nm. The particle size of the spherical aggregates can be further reduced by milling process.
In accordance with another embodiment of the present disclosure, the hydrophobic carbon black is characterized by having the water contact angle in the range of 135o to 165o, the chlorine content in the range of 15 mass% to 25 mass%, and the spherical aggregates having the particle size of less than 390 µm, the surface area in the range of 490 m2/g to 565 m2/g, the pore volume in the range of 0.25 m2/g to 0.35 m2/g and the pore diameter in the range of 2.5 nm to 4.0 nm.
In an exemplary embodiment, the hydrophobic carbon black is characterized by having the water contact angle of 153º, the chlorine content of 23 mass%, and the spherical aggregates have an average particle size of 384 µm, the surface area of 560 m2/g, the pore volume of 0.32 m2/g, and the pore diameter of 3.6 nm.
In another exemplary embodiment, the hydrophobic carbon black is characterized by having the water contact angle of 140º, the chlorine content of 23 mass%, and the spherical aggregates have an average particle size of 384 µm, the surface area of 497 m2/g, the pore volume of 0.25 m2/g, and the pore diameter of 2.74 nm.
In still another exemplary embodiment, the hydrophobic carbon black has water contact angle of 160o.
The hydrophobic carbon black of the present disclosure has bonded chlorine, which improves the hydrophobicity of the carbon black. Further, the process of the present disclosure does not require an additional step of halogenation, which is conventionally required to improve the hydrophobicity of the carbon black. The use of waste chlorinated feed eliminated the step of the halogenation of the carbon black thereby making the process economic and environment friendly. Further, the hydrophobicity of carbon black is independent from the amount of the compounds having low boiling point present in the feed.
The process of the present disclosure provides a highly efficient process for the production of carbon black of different morphologies. The morphology of the hydrophobic carbon black of the present disclosure depends on the amount of the compounds having low boiling point present in the feed.
In an embodiment, the feed having higher amount of the compounds having low boiling point produced the carbon black with spherical aggregates such as a bunch of grapes. The so obtained carbon black has higher surface area > 450 m2/g.
The process of the present disclosure provides a chlorinated hydrophobic carbon black having high surface area and spherical aggregates that can be used as a polymer additive or filler. The hydrophobic carbon black of the present disclosure can improve the strength of the polymer, waterproofing coating and paints.
In another embodiment, the feed having lower amount of the compounds having low boiling point produces solid lump such as carbon material of low surface area.
The process of the present disclosure provides a chlorinated hydrophobic carbon black having lower surface area and lump-like structure that can also be used as porous fillers in polymer composite.
Further, the HCl gas so produced during the process of the present disclosure is an additional valuable product that is directly recycled in vinyl chloride monomer (VCM) plant or in other plant or can be sold in usable form.
The process of the present disclosure provides a chlorinated hydrophobic carbon black in a single step which does not require further surface treatment or a step of chlorination after the reaction.
The process of the present disclosure is simple and requires mild reaction conditions such as a processing temperature in the range of 200 oC to 250 °C and the like for producing chlorinated hydrophobic carbon black. The process of the present disclosure does not generate waste effluent.
In accordance with the present disclosure, the dehydrochlorination of the chlorinated heavier hydrocarbon present in the feed starts forming the carbon black as per Scheme 1.
In accordance with an embodiment of the present disclosure, in a chlorinated waste a Lewis acid catalyst is added at ambient temperature to obtain a mixture. The mixture is heated to initiate dehydrochlorination and as the temperature reaches > 85 °C, the compounds having low boiling point (EDC) start to reflux which are condensed and again come back to the reaction mass.
The temperature of the reaction mass is further increased to remove the distilled hydrocarbon from the reaction mass to obtain a solid mass. During the dehydrochlorination of chlorinated hydrocarbon heavier molecules present in the waste feed, the formation of carbon black is initiated as per the scheme 1 as shown in Fig. 1. During dehydrochlorination reaction C=C double bond forms which further recombine owing through its catenation property generating higher carbon chain or forms cyclic products. In this process, due to dehydrochlorination the HCl gas is evolved and the reaction mass becomes denser which leads to the formation of the carbon black.
The foregoing description of the embodiments has been provided for purposes of illustration and not intended to limit the scope of the present disclosure. Individual components of a particular embodiment are generally not limited to that particular embodiment, but, are interchangeable. Such variations are not to be regarded as a departure from the present disclosure, and all such modifications are considered to be within the scope of the present disclosure.
The present disclosure is further illustrated herein below with the help of the following experiments. The experiments used herein are intended merely to facilitate an understanding of the ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the experiments should not be construed as limiting the scope of embodiments herein. These laboratory scale experiments can be scaled up to industrial/commercial scale and the results obtained can be extrapolated to industrial/commercial scale.
EXPERIMENTAL DETAILS
Process for the preparation of hydrophobic carbon black in accordance with the present disclosure
Two types of chlorinated waste feeds were used to prepare hydrophobic carbon black. The composition of these two types of the feeds is provided in Table 1.
Table 1 Composition of chlorinated waste feed in accordance with the present disclosure
Component Chlorinated waste Type A (mass%) Chlorinated waste Type B (mass%)
1,2-Dichloroethane (EDC) 34 to 40 6 to 8
1,1,2-trichloroethane (TCA) 10 to 14 45 to 50
1,1,2,2-tetrachloroethane 4 to 6 1 to 2
Pentachloroethane (PCE) 1 to 1.5 0.05 to 0.5
Hexachloroethane 00 2 to 3
Unknown high boilers (chlorinated compounds having b.p. >200 oC) 37 to 42 41 to 50

Example 1
1073 g of chlorinated hydrocarbon waste of type A was taken in 2 litres three neck round bottom flask which was equipped with an overhead stirrer, circulating chilled water condenser and kept in oil bath for heating. Lewis acid catalyst (anhydrous AlCl3) 1.6 mass% (17.9 g) was added to the chlorinated hydrocarbon waste of type A under stirring at 30 oC to obtain a mixture. A temperature of the oil bath was raised by further heating to attain the temperature of 150 ?C in a time period of 2 hours 30 minutes. As the temperature reaches 85 ?C, the low boilers (compounds having a low boiling point) started to reflux and the reflux was continued for 6 hours to obtain a reaction mass. The reaction mass became more viscous and hydrogen chloride gas so evolved was scrubbed in 20% NaOH solution trap. After 6 hours the chilled water condenser was removed. The temperature of the oil bath was further raised to a temperature of 220 oC in the time period of 4 hours for distilling out compounds having higher boiling point (undistilled compounds) to leave a solid mass that was dark black in colour with liberation of HCl gas. The black solid mass was washed with dichloromethane for three times followed by washing with hot water for three times and the so obtained washed black carbon material was dried under air in an oven at 120 ?C for 4 hours to obtain a hydrophobic carbon black.
The so obtained hydrophobic carbon black was 70 g (~6.7 mass% yield) having 23 mass% of chlorine.
Fig. 2(a) illustrates a process flow diagram for carbon black formation by re-circulation (reflux-condensation) of the low boilers.
Example 2
Example 2 was carried out similar to example 1, except using 1037 g of chlorinated hydrocarbon waste of type B and 17.2 g of anhydrous AlCl3 as a catalyst (1.6 mass%). The so obtained hydrophobic carbon black was 167 g (16.1 mass% yield) having 21 mass% of chlorine.
Example 3
Example 3 was carried out similar to example 1, except using 1000 g of chlorinated hydrocarbon waste of type B and 25.2 g of anhydrous AlCl3 (2.5 mass%) as a catalyst. The so obtained hydrophobic carbon black was 189 g (18.9 mass% yield) having 24 mass% of chlorine.
Example 4
Example 4 was carried out similar to example 1, except using 1066 g of chlorinated hydrocarbon waste of type B without catalyst. The so obtained hydrophobic carbon black was 38 g (3.5 mass% yield) having 23 mass% of chlorine.
Example 5
Example 5 was carried out similar to example 1, except using 1019 g of a mixture of chlorinated waste type A and chlorinated waste type B (equal amounts), and 26 g of anhydrous AlCl3 (2.5 mass%) as a catalyst. The so obtained hydrophobic carbon black was 125 g (12.3 mass% yield) having 19 mass% of chlorine.
Example 6
Example 6 was carried out similar to example 1, except using 1300 g of chlorinated hydrocarbon waste of type A without having reflux-condensation step. A direct distillation of the low boilers was done in the presence of catalyst. The so obtained hydrophobic carbon black was 62 g (4.76 mass% yield) having 27 mass% of chlorine.
Fig. 2(b) illustrates a process flow diagram for the carbon black formation without re-circulation (reflux-condensation) of the low boilers. The yield of the carbon black depends on the presence of compounds having high boiling points and unknown heavier compounds. In type B feed unknown heavier compounds are high. Halogen atom attached with the carbon generates more surface negative charge. Water dipole is negative due to more electronegativity of oxygen than that of hydrogen. So, the chlorinated carbon become repellent to water causing hydrophobicity. Example 3 showed highest yield due to high amount of unknown high boilers in the feed (Feed B) and high catalyst loading.
Analysis of the so obtained hydrophobic carbon black in accordance with the process of the present disclosure
The hydrophobic carbon black so obtained in examples 1 to 5 were analyzed for BET surface area, FTIR spectroscopy and chlorination percentage.
Determination of the chlorine content of the hydrophobic carbon black: The oxygen flask combustion method was used for the determination of chlorine content in the carbon sample. The carbon sample combustion was done in combustion unit (EAI Exeter analytical, UK Ltd.), the combustion unit consisted of combustion chamber, a glass flask having platinum basket attached to the cap of flask and an ash less filter paper holder (cellulose paper). Nearly 20 mg of carbon sample was weighed in paper holder, folded and kept in platinum basket properly. In the glass flask, 20 mL distilled water along with 1 mL 10 % KOH and 0.1 mL 30% H2O2 solution was taken. The flask was flushed with oxygen for 5 minutes and the platinum basket having carbon sample holder tighten on the mouth of the flask. Then the flask was kept inside the combustion chamber and combustion of carbon sample was done. The liberated chloride ion absorbed in flask water solution and the chloride content is then measured by titration against AgNO3 solution using auto titrator (Metrohm 888 TTRANDO). The results of BET surface area and the chlorination percentages are as shown in table 2.
Table 2 Analysis of the hydrophobic carbon black prepared in accordance with the process of the present disclosure
Example no. Type of chlorinated waste Yield
(mass%) BET surface area (m2/g) Pore volume
(m2/g) Pore diameter (nm) Chlorination % Contact angle (degree)
Example 1 A 6.7 560 0.32 3.56 23 153
Example 2 B 16.1 0.5 NA NA 21 146
Example 3 B 18.9 2.4 0.001 2.90 24 160
Example 4 B 3.5 00 NA NA 23 147
Example 5 A+B (1:1 mass ratio) 12.3 497 0.25 2.74 19 140
Example 6 A 4.76 122 0.15 7.0 27 167
The feed A i.e., chlorinated waste type A having the higher amount of EDC (in example 1), produced the carbon black having spherical aggregate (particle-like grapes bunch-see the SEM images as shown in Fig. 3 (a-d)). This could be due to the fact that when the reaction temperature reaches > 85 °C, the compounds having low boiling point (EDC) started to reflux and returned to the reaction mass after condensation. The EDC may have entered in the pores of carbon or may adsorbed by the generated carbon material and acted as a template which led to formation of a spherical carbon. Upon increase in the reaction temperature of 220 oC during distillation in step (iii), the low boilers were either adsorbed by the generated carbon or un-reacted are distilled out and leave behind a particular morphology porous carbon material having the surface area > 450 m2/g.
The feed B, i.e., chlorinated waste type B having the lower amount of EDC, (example 2) produced the carbon black having lumps like structure (refer the SEM images as shown in Fig. 4 (a-d)). The surface area of the hydrophobic carbon black of the example 2 has the surface area of 0.5 m2/g.
FTIR of the so obtained carbon black obtained from example 1 showed small band at 1437 cm-1 due to C-H bending of CH2 and a sharp band 1600 cm-1 due to C=C stretching of aromatic ring (refer Fig. 5(a) in transmittance mode). Small IR band at 2924 cm-1 and 2855 cm-1 are specially designated as aliphatic C-H and CH2 stretching vibration bands. Moreover, the frequency at 660 cm-1 is due to the C-Cl stretching vibration. A band was also observed at 1705 cm-1 indicating C=O stretching of carboxylic group, which arise due to air oxidation of carbon material while the carbon formation or oxidation during the process. The FTIR spectra revealed the more aromatic incorporation in the carbon structure, confirming the plausible mechanism of Scheme I. The higher aromatic content in the carbon indicated the dehydrochlorination followed by cyclization and aromatization and the same has been indicated in Scheme 1. Weak intensity of C-H bending at 1437 cm-1 and also weak stretching of aliphatic C-H and CH2 in range of 2924 cm-1 and 2855 cm-1 indicates the low aliphatic carbon in the resulted carbon material. However, in the carbon black of example 2 as shown in Fig. 5(b) these peaks are prominent. This incorporation can be explained by unsaturation of chlorinated hydrocarbon by dehydrochlorination and chain propagation followed by cyclization and aromatization. The ring could be of polyaromatic type by combining more aromatic rings. Similarly, the aliphatic rings can be more than one.
Example 2 using chlorinated waste type B feed with less amount of low boiler (EDC) led to the solid lump like carbon material having surface area < 2 m2/g. This could be due to less amounts of EDC (compound having low boiling point, present in the feed thereby obtaining the carbon black more diffused as here was no sufficient EDC available to adsorb which could give a template effect for the formation of spherical type carbon morphology. The IR spectra of carbon black of example 2 showed the sharp stretching vibration band at 2924 cm-1 and 2864 cm-1 of aliphatic CH and CH2. A sharp C-H bending band 1441 cm-1 indicated the more aliphatic incorporation in the carbon structure (refer FTIR spectra in Fig. 5(b)).
The carbon black of Example 5 prepared by using an equal amount of both the chlorinated waste type A feed and the chlorinated waste type B feed are more similar to those obtained by using the chlorinated waste type A feed having higher amount of EDC (refer FTIR spectra in Fig. 5(c)). Mixing equal amount of both the chlorinated waste type A feed and the chlorinated waste type B feed resulted in a feed composition which contain enough EDC to get the template effect and the so obtained carbon black had a surface area of > 450 m2/g.
The amounts of low boilers (compounds having low boiling point) affected the morphologies of the carbon black obtained by the process of the present disclosure. However, the carbon black of the present disclosure showed the chlorination percentage in the range of 21 mass% to 27 mass%, and the water contact angle of > 140 degree. So, it is revealed that the presence of low boilers (compounds having low boiling point) in high amounts (proportion) in the chlorinated waste feed showed the inbuilt template effect and produced the different morphologies of the carbon black.
TECHNICAL ADVANCEMENTS
The present disclosure described herein above has several technical advantages including, but is not limited to, the realization of a process for the preparation of hydrophobic carbon black that
• is highly efficient to produce hydrophobic carbon black of different morphologies;
• is simple, requires mild conditions and does not generate effluent;
• simultaneously produces valuable products;
• does not require additional surface treatment or chlorination step;
• utilizes industrial waste; and
• produces the carbon black having high surface area and hydrophobicity.
The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
The foregoing description of the specific embodiments so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.
Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.
The use of the expression “at least” or “at least one” suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the disclosure to achieve one or more of the desired objects or results.
Any discussion of documents, acts, materials, devices, articles or the like that has been included in this specification is solely for the purpose of providing a context for the disclosure. It is not to be taken as an admission that any or all of these matters form a part of the prior art base or are common general knowledge in the field relevant to the disclosure as it existed anywhere before the priority date of this application.
The numerical values mentioned for the various physical parameters, dimensions or quantities are only approximations and it is envisaged that the values higher/lower than the numerical values assigned to the parameters, dimensions or quantities fall within the scope of the disclosure, unless there is a statement in the specification specific to the contrary.
While considerable emphasis has been placed herein on the components and component parts of the preferred embodiments, it will be appreciated that many embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other changes in the preferred embodiment as well as other embodiments of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation. ,
Claims:WE CLAIM:
1. A process for the preparation of hydrophobic carbon black, said process comprising the following steps:
• charging a predetermined amount of a feed in a reactor followed by adding a predetermined amount of at least one catalyst at a temperature in the range of 20 oC to 50 oC to obtain a mixture;
• heating said mixture to a first predetermined temperature for a first predetermined time period with simultaneous refluxing of compounds having low boiling point from said feed at a second predetermined temperature for a second predetermined time period to obtain a reaction mass;
• raising the temperature of said reaction mass to a third predetermined temperature for a third predetermined time period for removing unreacted chlorinated compounds from said reaction mass to obtain a solid mass; and
• washing said solid mass by using at least one solvent followed by washing with hot water and filtering to obtain solids and drying said solids at a fourth predetermined temperature for a fourth predetermined time period to obtain said hydrophobic carbon black.
2. The process as claimed in claim 1, wherein said feed is at least one selected from a first feed and a second feed; wherein said first feed is a chlorinated hydrocarbon waste having predetermined concentrations of compounds having low boiling point and compounds having high boiling point; and said second feed is a chlorinated hydrocarbon waste having predetermined concentrations of compounds having low boiling point and compounds having high boiling point.
3. The process as claimed in claim 2, wherein said first feed is a chlorinated hydrocarbon waste comprising compounds having low boiling point and compounds having high boiling point,
wherein said compounds having low boiling point are selected from
• 30 mass% to 40 mass% of 1, 2 dichloroethane (EDC),
• 10 mass% to 15 mass% of 1,1,2 trichloroethane (TCA), and
• 4 mass% to 6 mass% of 1,1,2,2-tetrachloroethane,
wherein said compounds having high boiling point are selected from
• 1 mass% to 3.0 mass% of pentachloroethane (PCE), and
• 35 mass% to 45 mass% of chlorinated hydrocarbons having boiling point greater than 200 oC.
4. The process as claimed in claim 2, wherein said second feed is a chlorinated hydrocarbon waste comprises compounds having low boiling point and compounds having high boiling point,
wherein said compounds having low boiling point are selected from
• 5 mass% to 10 mass% of 1, 2 dichloroethane (EDC),
• 45 mass% to 50 mass% of 1,1,2 trichloroethane (TCA), and
• 1 mass% to 2 mass% of 1,1,2,2-tetrachloroethane, and
wherein said compounds having high boiling point are selected from
• 0.05 mass% to 0.5 mass% of pentachloroethane (PCE),
• 2 mass% to 3 mass% of hexachloroethane, and
• 40 mass% to 50 mass% of chlorinated hydrocarbons having boiling point greater than 200 oC.
5. The process as claimed in claim 1, wherein said compounds having low boiling point have a boiling temperature in the range of 60 oC to 150 oC.
6. The process as claimed in claim 1, wherein said compounds having low boiling point are present in an amount in the range of 1 mass% to 70 mass% with respect to the total mass of the feed.
7. The process as claimed in claim 1, wherein acid fumes liberated in step (ii) and step (iii) are trapped in a scrubber.
8. The process as claimed in claim 1, wherein said predetermined amount of said feed is in the range of 96 mass% to 99 mass% with respect to the total mass of said mixture; and said predetermined amount of said catalyst is in the range of 1 mass% to 4 mass% with respect to the total mass of said mixture.
9. The process as claimed in claim 1, wherein said first predetermined temperature is in the range of 125 oC to 160 oC.
10. The process as claimed in claim 1, wherein said first predetermined time period is in the range of 1 hour to 5 hours.
11. The process as claimed in claim 1, wherein said second predetermined temperature is in the range of 75 oC to 160 oC.
12. The process as claimed in claim 1, wherein said second predetermined time period is in the range of 3 hours to 10 hours.
13. The process as claimed in claim 1, wherein said third predetermined temperature is in the range of 200 oC to 250 oC.
14. The process as claimed in claim 1, wherein said third predetermined time period is in the range of 2 hours to 6 hours.
15. The process as claimed in claim 1, wherein said fourth predetermined temperature is in the range of 100 oC to 140 oC.
16. The process as claimed in claim 1, wherein said fourth predetermined time period is in the range of 2 hours to 6 hours.
17. The process as claimed in claim 1, wherein said at least one catalyst is a Lewis acid catalyst selected from the group consisting of AlCl3, ZnCl2, BF3 and SnCl4.
18. The process as claimed in claim 1, wherein said hydrophobic carbon black is characterized by having
• a water contact angle in the range of 130o to 170o;
• a chlorine content in the range of 15 mass% to 30 mass%; and
• spherical aggregates having a particle size of less than 750 µm, a surface area in the range of 450 m2/g to 600 m2/g; a pore volume in the range of 0.20 m2/g to 0.40 m2/g, and a pore diameter in the range of 2 nm to 5 nm.
19. The process as claimed in claim 1, wherein said hydrophobic carbon black is characterized by having
• a water contact angle in the range of 135o to 165o;
• a chlorine content in the range of 15 mass% to 25 mass%; and
• spherical aggregates having a particle size of less than 390 µm, a surface area in the range of 490 m2/g to 565 m2/g, a pore volume in the range of 0.25 m2/g to 0.35 m2/g, and pore diameter in the range of 2.5 nm to 4.0 nm.
20. Hydrophobic carbon black prepared by using the process as claimed in claims 1-17.
21. The hydrophobic carbon black as claimed in claim 20 is characterized by having
• a water contact angle in the range of 130o to 170o;
• a chlorine content in the range of 15 mass% to 30 mass%; and
• spherical aggregates having a particle size of less than 750 µm, a surface area in the range of 450 m2/g to 600 m2/g, a pore volume in the range of 0.20 m2/g to 0.40 m2/g, and a pore diameter in the range of 2 nm to 5 nm
22. The hydrophobic carbon black as claimed in claim 20 is characterized by having
• a water contact angle in the range of 135o to 165o;
• a chlorine content in the range of 15 mass% to 25 mass%; and
• spherical aggregates having a particle size of less than 390 µm, a surface area in the range of 490 m2/g to 565 m2/g, a pore volume in the range of 0.25 m2/g to 0.35 m2/g, and pore diameter in the range of 2.5 nm to 4.0 nm.
Dated this 16th day of November, 2023

_______________________________
MOHAN RAJKUMAR DEWAN, IN/PA – 25
of R.K.DEWAN & CO.
Authorized Agent of Applicant

TO,
THE CONTROLLER OF PATENTS
THE PATENT OFFICE, AT MUMBAI