DESC:SYSTEM FOR SYNTHESIS OF FIBROUS NANOSPHERE OF SILICA VIA A CONTINUOUS FLOW PROCESS AND PROCESS THEREOF

FIELD OF THE INVENTION
[0001] The present invention relates to a method of synthesis of fibrous nano-sphere of silica. More particularly, the present invention relates to a method and system for synthesis of fibrous nano-sphere of silica via a scalable continuous flow process, wherein the process requires lesser efforts and time, with an added advantage of improved scalability.

BACKGROUND OF THE INVENTION
[0002] Generally, synthesis of fibrous nanosphere of silica is conventionally carried by reacting compounds using conventional batch processes like microwave, autoclave and reflux. Synthesis in batch process of fibrous nanospheres is carried either heating at 125°C for 1 hour in a microwave, 125°C for 4 hours in an autoclave, or refluxing in a round-bottom flask based open vessel reactor protocol at 130°C for 2-12 hours. Further these processes are time-consuming and not very scalable. Moreover, these conventional procedures require initial preparation of precursor emulsion, which on heating at the above said temperatures and equipment’s could yield the desired fibrous nanosphere morphology.

[0003] The above mentioned, method pertaining to the synthesis of KCC-1 through batch (conventional or laboratory method) include a microwave-assisted hydrothermal technique and a technique that involves high temperature and pressure heating in an autoclave. The main problem associated with the existing conventional synthetic processes carried out in batch for the synthesis of fibrous nanospheres of silica are poor scalability, tedious and time-consuming procedure.

[0004] In order to overcome the abovementioned shortcomings, there is a need to develop a method for synthesis of fibrous nanosphere of silica via a scalable continuous flow process that requires lesser efforts and time, with improved scalability.

OBJECT OF THE INVENTION
[0005] The object of the present invention is synthesis of fibrous nanosphere of silica via a scalable continuous flow process.
[0006] Another object of the present invention is to synthesis fibrous nanosphere of silica via a scalable continuous flow process, with improved scalability.
[0007] Yet another object of the present invention is to synthesize fibrous nanospheres of silica at higher temperatures that require extremely less reaction time via a scalable continuous flow process.
[0008] Yet another object of the present invention is to simplify the synthesis process of fibrous nanosphere of silica by elimination of intermediate steps, and yet obtain the same fibrous morphology of the formed particles.

SUMMARY
[0009] In one aspect of the present disclosure, a system for synthesizing fibrous nanospheres of silica (KCC-1) is disclosed. The system comprises a stirrer (1) receiving an emulsion solution for stirring, at least one pump (2) connected with the stirrer (1), receiving the stirred emulsion, at least one tubular reactor coil (4) placed inside a temperature controller (5), a back pressure regulator (6) connected with the temperature controller (5) to provide a streamlined and continuous flow of a reacted mixture obtained through a reaction of a reacting mixture at the tubular reactor coil (4). The temperature controller (5) is connected with the at least one pump (2) for supplying the emulsion or individual reagents separately, into the tubular reactor coil (4). The reacted mixture is centrifuged and calcined at the back pressure regulator (6) to generate fibrous nanospheres of silica (KCC-1).

[0010] In another aspect of the present disclosure, a process of synthesizing fibrous nanospheres of silica (KCC-1) is disclosed. The process comprises the steps of providing an emulsion for synthesis, stirring the emulsion using a stirrer, supplying at least one of the emulsion or individual reagents, separately into a tubular reactor coil (4) placed inside a temperature controller (5), by at least one pump (2), wherein a reaction takes place between a reacting mixture comprising emulsion or individual reagents, in the tubular reactor coil (4), controlling a temperature of the reaction process, uniformly during the progress of the reaction by the temperature controller (5) and receiving a reacted mixture obtained through the reaction at the tubular reactor coil (4) by a back pressure regulator (6), from the tubular reactor coil (4). The process further comprises the steps of applying a pressure by the back pressure regulator (6), to generate a streamlined and continuous flow of reacted mixture, collecting the pressurized reacted mixture from an outlet of the back pressure regulator (6) and centrifuging and calcining the collected reacted mixture at the back pressure regulator (6) to generate fibrous nanospheres of silica (KCC-1).

BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The detailed description is described with reference to the accompanying figures.
[0012] Figure 1, illustrates a schematic representation of a system for synthesizing fibrous nanospheres of silica via a scalable continuous flow process in accordance with the present disclosure.
[0013] Figure 2, illustrates a system setup for synthesis of fibrous nanospheres of silica obtained using an emulsion via a scalable continuous flow process in accordance with the present disclosure.
[0014] Figure 3, illustrates a system setup for synthesis of fibrous nanospheres of silica obtained using an emulsion prepared using two different phase solutions in accordance with the present disclosure.
[0015] Figure 4, illustrates a comparison of SEM (Scanning Electron Microscopy) images obtained for a series of experiments carried out at various temperatures for various residence (reaction) times.
[0016] Figure 5, illustrates a comparison of HRTEM images obtained for a series of experiments carried out at various temperatures for various residence (reaction) times.
[0017] Figure 6, illustrates a tabular form of experimental data of the synthesis carried out (experiment 1) with a series of temperatures and with various residence (reaction) times.
[0018] Figure 7, illustrates a tabular form of experimental data of the synthesis carried out (experiment 2) with a temperatures ranging from 150°C to 175°C, at residence (reaction) times from 7.5 minutes to 60 minutes.
[0019] Figure 8, illustrates a tabular form of experimental data of the synthesis carried out (experiment 3) with a series of temperatures and with various residence (reaction) times.
[0020] Figure 9, illustrates a tabular form of comparison of characteristics of the fibrous nanospheres of silica (KCC-1) obtained through Continuous Flow Synthesis and various conventional batch methods.

DETAILED DESCRIPTION OF INVENTION
[0021] The present invention relates to a method for synthesis of fibrous nanosphere of silica. More particularly, the present invention relates to a method for synthesis of fibrous nanosphere of silica via a scalable continuous flow process that requires lesser efforts and time, with an added advantage of improved scalability.

[0022] The present invention relates to synthesis of desired catalytic nanomaterial support such as fibrous nanospheres of silica formed at a higher temperature, and involving less reaction via a scalable continuous flow process. Conventionally for the synthesis of fibrous nanospheres of silica, an initial mixture has to be prepared comprising two-part solution, wherein one part is aqueous solution and another part organic solution, wherein both are mixed together to produce an emulsion. The present invention aims to eliminate the intermediate steps, wherein the need of a ready emulsion (initial mixture) before the heating process is eliminated. In the present invention the aqueous solution and the organic solution can be pumped individually/separately through the flow reactor, thereby yielding ultimately the same fibrous morphology of the formed particles.

[0023] The present invention aims to ease the conventional synthetic procedure by making it more convenient for simple synthesis within lesser times. The product thus obtained, is comparable in its surface characteristics with that reported; but with an advantageous decrease by half or more of the reaction time, making the synthetic process safe and scalable.

[0024] The main aspect of the present invention relates to a process of synthesis by continuous flow processing in place of the conventional batch mode of production. Figure 1 illustrates a system set-up is employed for the synthesis of fibrous nanosphere of silica in accordance with the present disclosure. The system comprises a stirrer (1), at least one pump (2) connected with the stirrer (1), a tubular reactor coil (4), a temperature controller (5) and a back pressure regulator(6)(BPR). The stirrer (1) comprises a magnetic stirrer plate. The pump supplies the agents/reagents to the tubular reactor coil (4). The pump supply reagents either in the form of a complete pre-formed emulsion or individual emulsifying solutions) to the tubular reactor coil (4).In one embodiment, one or more pumps are used herein the present disclosure. The pumps may be connected to one or more stainless steel metallic 1/8th preconditioning loops to maintain the stability in temperature that act as a bridge between the pumps and the tubular reactor coil. The tubular reactor coil (4) is the reaction junction where the reaction takes place between reagents to yield the product. The tubular reactor coil (4) is placed inside the temperature controller (5). The temperature controller (5) maintains the temperature of the process required during the progress of the reaction, uniformly, until the product is formed. Further to bring down the reaction mixture post reaction to room temperature before collection, 1/4th inch cooling loops are placed in the temperature controller (5). The temperature controller (5) comprises a heating device or a cooling device used to regulate temperature of the reaction mixture at a temperature suitable and conducive for reaction progress. The heating device may comprise a conventional oil bath or a high temperature furnace. Further temperature controller (5) is connected to the back pressure regulator (6), so that, said loops are in turn connected to the back-pressure regulator to collect the product after reaction is streamlined and in a continuous manner. The back pressure regulator (6) provides a pressure so as to avoid the reagents / reaction mixture to evaporate when the temperature involved is above the boiling point(s) reagents / reaction mixture. The system further comprises a gas supply unit (8) connected with back pressure regulator (6) for supplying Nitrogen at the back pressure regulator (6).

[0025] The precursor used to synthesis the formation of KCC-1 (fibrous nanospheres of silica) is an emulsion; that effectively consists of two immiscible but homogeneous solutions. Thus, the emulsion was prepared using two different phase solutions – an aqueous phase solution and an organic phase solution. The aqueous phase solution comprises a hydrolyser and a surfactant and the organic phase solution comprises a precursor of silica in a suitable organic solvent. The Aqueous phase being a mixture of Urea as hydrolyser, Cetyltrimethyl ammonium bromide (CTAB) as surfactant and Distilled water. The organic phase solution further may comprise a stabilizer. In one embodiment, the stabilizer is not used in the organic phase solution. The organic solvent comprises a solvent having high boiling point. The organic solvent is selected from solvents not only limited to Cyclohexane, p-Xylene, Decalin. The organic phase solution comprises Tetraethyl orthosilicate (TEOS) used as precursor for silica, and 1-Pentanol used as stabilizer in the present disclosure. The reagents and chemicals are not limited to the ones used in the present disclosure, and are extended to other forms and types of reagents and chemical. Thus, other similar categories of hydrolysers, surfactants, silica precursors, stabilizers and solvents also can achieve the similar result mentioned in the present disclosure.

[0026] A process of synthesizing KCC-1 (fibrous nanospheres of silica) comprises a step by step process. The process comprises of allowing the KCC-1 emulsion to stand for more than 30 minutes, during the settling process phase separates into two components (emulsifying aqueous and organic liquids), therefore, to prevent the separation of the phases, the KCC-1 emulsion is kept under constant stirring using a magnetic stirrer. At least one pump is used to supply the KCC-1 emulsion into the tubular reactor coil. The pump is connected to stainless steel metallic 1/8th and 1/4th inch loops that are placed in oil bath or high temperature furnace to regulate temperature. The 1/8th reactor metal preconditioning loop (3) is connected in series to the 1/4th reactor loop (3a), kept in an oil-bath to control the temperature. Further, the reaction mass (reacting mixture)is allowed to flow through a series of metal tubes connected together (coil), with a view to increase the surface area for enabling faster cooling, till the reaction mass reaches at the Back-Pressure Regulator (BPR). The back pressure regulator (6) is fitted at the end of the system setup to maintain a streamlined and continuous flow of the reaction mass. The reacted mixture containing the product, fibrous nanospheres of Silica (KCC-1)may be collected finally from an outlet of the back pressure regulator (6) into a collector vessel (7) and further processed by centrifugations and calcinations to yield the final KCC-1 fibrous nanospheres of silica.

Experimental Analysis
Experiment 1:
[0027] The stoichiometry of the reaction is kept as one part aqueous and another part organic, which is a standard set up reported in the literature. Initially, the synthesis is carried out in a standard format using an emulsion. The present invention described a synthesis using the hydrothermal route, wherein the desired nanospheres were obtained by microwaving a pre-prepared emulsion at 120°C for 60 minutes. The emulsion is the precursor for the formation of KCC-1 effectively consisted of two immiscible but homogeneous solutions (in stoichiometric equivalents of 1:1) – Aqueous phase being a mixture of hydrolyser (Urea), surfactant (Cetyltrimethyl ammonium bromide) and Distilled water; and Organic phase comprising TEOS, the precursor for silica (Tetraethyl orthosilicate), Solvent (Cyclohexane) and stabilizer (1-Pentanol) in an organic solvent. Figure 2 illustrates an experimental setup for the same.

[0028] The reagents and chemicals are not limited to the reagents and chemical used in the present invention and are extended to other forms and types of reagents and chemicals too. Other similar categories of hydrolysers, surfactants, silica precursors, stabilizers and solvents can also be used in the present invention.

[0029] Any solvent having a high boiling point is used as an organic solvent in the experiments of the present invention, and selected from Cyclohexane (86°C), p-Xylene (135°C), Decalin (186°C). Solvents having higher boiling points not only limited to used herein in the experiment, other solvents having higher boiling points can also be used in the experiments; like Diethyl ether (250°C), should also work very well to yield similar results.

[0030] The stoichiometry of the reaction was kept standard throughout the experiments as 1:1, can be varied depending upon any particular morphology, size, shape or structure of KCC-1 desired. Referring to figure 2, illustrated is an experimental system setup for synthesis of fibrous nanospheres of silica obtained using an emulsion via a scalable continuous flow process in accordance with the present disclosure.

[0031] The synthesis is carried out at various temperatures, preferably at temperatures ranging from 100°C to 300°C, controlled by an oil-bath. The reaction pressure is applied in accordance with various temperatures using the back pressure regulator. The residence times of the synthesis, is the amount of time that the emulsion takes to react under the temperature within the continuous flow reactor, are set to have 15 minutes, 30 minutes, 45 minutes and 60 minutes. The flow rates needed to maintain such residence times is adjusted accordingly. The samples at 30 and 45 minutes residence times gave results comparable with the batch reported ones.

[0032] With the above synthesis yielding the morphology of the product as desired, the same reaction is carried at a higher temperature and pressure for obtaining the product within lesser residence times. This time, it was tried at a temperature of 175°C under a higher pressure of 19 bars. Here, the residence times (reaction times) are maintained at 11 minutes, 20 minutes, 30 minutes, 40 minutes and 50 minutes. Here also it is observed that yield of fibrous nanosphere of silica showed good results at residence times of 30 and 40 minutes. Thus, a series of experiments of synthesis process was carried out through a series of temperatures viz. 120°C to 200°C; at various residence (reaction) times from 2 minutes to 60 minutes. Figure 6 shows a tabular form of experimental data of the synthesis carried out (experiment 1) with a series of temperatures and with various residence (reaction) times.

Experiment 2:
[0033] Higher the boiling point of the solvent used, easier and more efficient is the techique,since the pressure involved in the overall process becomes much lesser leading to better safety, energy efficiency, and feasibility of the process. A series of optimization experiments carried out to provide an optimum temperature and time that would produce a desired morphology. The series of experiments involved an even higher boiling point solvent, Decalin (Boiling Point 190°C). The overall pressure required for the process was much lower due to high-boiling Decalinsolvent, making the process safer and economical in all respects. The series of experiments explored at temperatures 150°C to 175°C, at residence (reaction) times from 7.5 minutes to 60 minutes. Figure 7 shows a tabular form of experimental data of the synthesis carried out (experiment 2) with a temperatures ranging from 150°C to 175°C, at residence (reaction) times from 7.5 minutes to 60 minutes.

Experiment 3:
[0034] The present invention has also been analyzed to obtain the final product KCC-1 without actually feeding the emulsion in the first place; but by starting directly with the emulsifying reagents. A series of experiments were carried out using two separate homogeneous solutions as discussed above. The experimental system setup used was same as in the above experiments; with the only difference here being two pumps employed, one for each aqueous and organic solution; and a T-Junction (9) connecting two pumps (2a, 2b) and the tubular reactor coil, the T-junction is used for mixing two solutions together briefly before letting them enter into the tubular reactor coil. Figure 3 illustrates such system setup for synthesis process in accordance with the present disclosure.

[0035] The synthesis is carried out using two pumps (one for the aqueous solution and another for the organic one) at 150°C controlled by the high temperature furnace. The reaction pressure is set to be 8.5 bars. The residence times of the synthesis; are set to be 30 minutes, 60 minutes, 90 minutes and 120 minutes. The flow rates needed to maintain such residence times, are adjusted accordingly. The samples at 90 and 120 minutes residence times gave results comparable with the batch reported ones.

[0036] With the above synthesis yielding the morphology of the product as desired, the same reaction is carried at a higher temperature and pressure for obtaining the product within lesser residence times. The experiment was carried out at a temperature of 175°C under a higher pressure of 15 bars. Here, the residence times (reaction times) were maintained at 20 minutes, 40 minutes, 60 minutes, 80 minutes, and 100 minutes. Thus, the series of experiments of synthesis process was carried out through a series of temperatures viz. 150°C to 200°C; at various residence (reaction) times from 20 minutes to 120 minutes. Figure 8 shows a tabular form of experimental data of the synthesis carried out (experiment 3) with a series of temperatures and with various residence (reaction) times.

[0037] The results obtained through the various sets of experiments elucidated above were quite comparable to the structure and morphology of the nanospheres of KCC-1 reported.

[0038] Results and Characterization:
The structure, shape and morphology of the fibrous nanospheres of silica (KCC-1) product were studied by the following microscopic characterization techniques:
1) FEG-SEM (Field Emission Gun Scanning Electron Microscopy)
2) HRTEM (High Resolution Transmission Electron Microscopy)

[0039] The other characterization details like yields, particle size analysis and surface area measurements were also studied. Figure 9 shows a tabular form of comparison of characteristics of the fibrous nanospheres of silica (KCC-1) obtained through Continuous Flow Synthesis and various conventional batch methods.

[0040] Figure 4 shows a comparison of SEM (Scanning Electron Microscopy) images obtained for a series of experiments carried out at various temperatures for various residence (reaction) times. Figure 4(1) shows a SEM image of fibrous nanospheres of silica obtained through conventional batch process by microwaving the emulsion at 125°C for 60 minutes. Figure 4(2) shows a SEM image of the product (fibrous nanospheres of silica) obtained through conventional batch process by refluxing the emulsion in an open bath, at 130°C for 6 hours (360 minutes). Figure 4(3) and 4(4) show SEM images of the product obtained using an Emulsion prepared with Decalin as solvent through Continuous Flow Synthesis at 150°C for 60 minutes and at 150°C for 45 minutes, respectively. Figure 4(5) shows a SEM image of the product obtained using Individual Solutions; where the organic was prepared with Cyclohexane as solvent; through Continuous Flow Synthesis at 150°C for 2 hours (120 minutes).

[0041] Figure 5 shows a comparison of HRTEM images obtained for a series of experiments carried out at various temperatures for various residence (reaction) times. Figure 5(1) shows an HRTEM image of fibrous nanospheres of silica obtained through conventional batch process by microwaving the emulsion at 125°C for 60 minutes. Figure 5(2) shows an HRTEM image of the product (fibrous nanospheres of silica) obtained through conventional batch process by refluxing the emulsion in an open bath, at 130°C for 9 hours (540 minutes). Figure 5(3) shows an HRTEM image of the product obtained using an Emulsion prepared with Decalin as solvent through Continuous Flow Synthesis at 150°C for 60 minutes. Figure 5(4) shows an HRTEM image of the product obtained using an Emulsion prepared with Cyclohexane as solvent through Continuous Flow Synthesis at 175°C for 20 minutes. Figure 5(5) and 5(6) show HRTEM images of the product obtained using an Emulsion prepared with Cyclohexane as solvent through Continuous Flow Synthesis at 150°C for 30 minutes under 8.5 bars pressure and at 150°C for 45 minutes under 8.5 bars pressure, respectively. Figure 5(7) shows an HRTEM image of the product obtained using Individual Solutions; where the organic was prepared with Cyclohexane as solvent; through Continuous Flow Synthesis at 150°C for 1.5 hours (90 minutes).

[0042] The following Examples illustrate the preferred embodiments of the instant invention. These are not intended to limit the scope of the invention. Rather, they are presented merely to facilitate the practice of the invention by those of ordinary skill in the art. The above representative experiments are elucidated in detail in below examples 1, 2 and 3.

Example 1
[0043] The experiment basically consisted of two steps: Emulsion preparation and actual reaction. Emulsion preparation: An emulsion was prepared using two different phase solutions – organic and aqueous. 3.0 grams of CTAB and 3.6 grams of Urea were dissolved into 300 ml of distilled de-ionized water to make up the aqueous phase. This solution was stirred using an overhead magnetic stirrer for 15 minutes at room temperature at 1400 rpm. Meanwhile, 15.0 grams of TEOS was mixed into 300 ml of Cyclohexane to make up the organic phase. This organic solution was added into the aqueous under continuous stirring conditions only, at the same speed and temperature, over a period of 20 minutes, very slowly and drop-wise. Once complete addition was over, the emulsion was allowed to further stir under the same conditions for another 20 minutes. Further, 18.0 ml of 1-Pentanol was added drop-wise into the emulsion over a period of 5 minutes under the same conditions. This was further allowed to continue being stirred for a period of 20 minutes. This step ultimately yielded the final milky-white emulsion that could be used to carry out the reaction with.

[0044] Actual Reaction: The emulsion prepared in the previous step was allowed to stir continuously using a magnetic stirrer plate throughout the duration of the reaction so as to avoid phase separation due to stagnancy. An HPLC Piston pump chosen for the experiment was initially calibrated before starting with the reaction to ensure that they supplied the set flow rate accurately. A Stainless Steel reactor coil tube of dimensions ¼” outer diameter and volume of 75 ml was chosen for the reaction. The volume of reactor tube is ranging from 70 ml to 115 ml. Further, the entire setup (pump leading to the tube reactor coil placed inside the temperature controller fixed at the end with BPR pressured using Nitrogen) was tested for leaks with both gas and solvent. On ensuring that the experimental assembly was indeed leak proof, the entire setup was pressurized up to 8.5 bars slowly and steadily with a rise of 1 bar/minute. Once the entire system was stabilized for around 10 minutes post pressurizing, the high temperature alumina furnace was set to 150°C and allowed to stabilize for around 10 minutes post temperature attainment. Once the entire system was at 150°C under 8.5 bars, the reaction was started. The Residence Time desired was 30 minutes at this temperature, which needed to be adjusted with the flow rate of the pump in accordance to the volume of the reactor coil. The flow rate of the pump was set such that it would deliver 2.5 ml/min of the continuously stirred emulsion into the reactor maintained at a temperature of 150°C and 8.5 bars. After 30 minutes of flow (since the residence time planned for was 30 minutes), the milky white reaction mass reached the BPR; through which it got collected into the collector vessel attached with the BPR.

[0045] Further, this reaction mass post reaction was collected externally into a glass bottle by intermittently releasing the pressure very slowly in order to collect the product without spraying it all over due to the gush of pressure release. This reaction mass visibly was much particulate as compared to the homogeneous emulsion that was the precursor; indicating that nanoparticles have formed. This mixture was allowed to phase separate naturally for a period of 10-15 minutes following which the upper organic layer was decanted away as much as possible leaving behind the denser aqueous part with nanoparticles. This was washed with ethanol and distilled water each thrice by centrifugation at around 8,000-10,000 rpm for 15-20 minutes until all the unreacted matter got eliminated away. The white solid obtained finally after all washings was allowed to air-dry overnight at 80°C. This dried product was further calcined at 550°C for 6 hours at a ramp-rate of 5°C/minute in order to burn off the excess surfactant. The final white product obtained is the desired nanospheres of silica (KCC-1); which was sampled for yield, morphological characterization through microscopy and surface area measurements.

Example 2
[0046] The experiment basically consisted of two steps: Emulsion preparation and actual reaction. Emulsion preparation: An emulsion was prepared using two different phase solutions – organic and aqueous. 10.0 grams of CTAB and 12.0 grams of Urea were dissolved into 500 ml of distilled de-ionized water to make up the aqueous phase. This solution was stirred using an overhead magnetic stirrer for 15 minutes at room temperature at 1400 rpm. Meanwhile, 100.0 grams of TEOS was mixed into 500 ml of Decalin to make up the organic phase. This organic solution was added into the aqueous under continuous stirring conditions only, at the same speed and temperature, over a period of 20 minutes, very slowly and drop-wise. Once complete addition was over, the emulsion was allowed to further stir under the same conditions for another 20 minutes. Further, 30.0 ml of 1-Pentanol was added drop-wise into the emulsion over a period of 5 minutes under the same conditions. This was further allowed to continue being stirred for a period of 20 minutes. This step ultimately yielded the final milky-white emulsion that could be used to carry out the reaction with.

[0047] Actual Reaction: The emulsion prepared in the previous step was allowed to stir continuously using a magnetic stirrer plate throughout the duration of the reaction so as to avoid phase separation due to stagnancy. An HPLC Piston pump chosen for the experiment was initially calibrated before starting with the reaction to ensure that they supplied the set flow rate accurately. An SS reactor coil tube of dimensions ¼” O.D. and volume 100 ml was chosen for the reaction. Further, the entire setup (pump leading to the tube reactor coil placed inside the temperature controller fixed at the end with BPR pressured using Nitrogen) was tested for leaks with both gas and solvent. On ensuring that the experimental assembly was indeed leak proof, the entire setup was pressurized up to 3.0 bars slowly and steadily with a rise of 1 bar/minute. Once the entire system was stabilized for around 10 minutes post pressurizing, the high temperature alumina furnace was set to 150°C and allowed to stabilize for around 10 minutes post temperature attainment. Once the entire system was at 150°C under 3.0 bars, the reaction was started.

[0048] The Residence Time desired was 60 minutes at this temperature, which needed to be adjusted with the flow rate of the pump in accordance to the volume of the reactor coil. The flow rate of the pump was set such that it would deliver 1.67 ml/min of the continuously stirred emulsion into the reactor maintained at a temperature of 150°C and 3.0 bars. After 60 minutes of flow (since the residence time planned for was 60 minutes), the milky white reaction mass reached the BPR; through which it got collected into the collector vessel attached with the BPR.

[0049] Further, this reaction mass post reaction was collected externally into a glass bottle by intermittently releasing the pressure very slowly in order to collect the product without spraying it all over due to the gush of pressure release. This reaction mass visibly was much particulate as compared to the homogeneous emulsion that was the precursor; indicating that nanoparticles have formed. This mixture was allowed to phase separate naturally for a period of 10-15 minutes following which the upper organic layer was decanted away as much as possible leaving behind the denser aqueous part with nanoparticles. This was washed with ethanol and distilled water each thrice by centrifugation at around 8,000-10,000 rpm for 15-20 minutes until all the unreacted matter got eliminated away. The white solid obtained finally after all washings was allowed to air-dry overnight at 80°C. This dried product was further calcined at 550°C for 6 hours at a ramp-rate of 5°C/minute in order to burn off the excess surfactant. The final white product obtained is the desired nanospheres of silica (KCC-1); which was sampled for yield, morphological characterization through microscopy and surface area measurements.

Example 3
[0050] A set of experiments were carried out through direct use of individual solutions as separate emulsifying reagents rather than using an emulsion for the process like before. Two solutions; aqueous and organic; were prepared separately. 3.0 grams of Urea and 3.6 grams of CTAB were weighed and dissolved into 300 ml of distilled de-ionized water until a clear homogeneous solution was formed. This comprised the aqueous phase of the reaction. 15.0 grams of TEOS and 18.0 ml of 1-Pentanol were dissolved into 300 ml of Cyclohexane to compose the organic phase. Both the solutions were separately filtered and stored in two separate clean dry bottles.

[0051] An HPLC Piston pump chosen for the experiment was initially calibrated before starting with the reaction to ensure that they supplied the set flow rate accurately. An SS reactor coil tube of dimensions ¼” O.D. and volume 75 ml was chosen for the reaction. Further, the entire setup (pump leading to the tube reactor coil placed inside the temperature controller fixed at the end with BPR pressured using Nitrogen) was tested for leaks with both gas and solvent. On ensuring that the experimental assembly was indeed leak proof, the entire setup was pressurized up to 8.5 bars slowly and steadily with a rise of 1 bar/minute. Once the entire system was stabilized for around 10 minutes post pressurizing, the high temperature alumina furnace was set to 150°C and allowed to stabilize for around 10 minutes post temperature attainment. Once the entire system was at 150°C under 8.5 bars, the reaction was started.

[0052] The experimental setup for the same comprised of two HPLC Piston pumps whose outlets were connected to a T-Junction externally that lead to the reactor coil. This coil was placed into the high temperature Alumina Furnace which was in series connected to the Swagelok Stainless Steel BPR-cum-collector. The residence time desired for the experiment was 120 minutes; whose flow rate needed to be tailored according to the volume of the reactor. The flow rates of the individual solutions were set to 312 µL/min making a total of 625 µL/min pumped through the reactor coil. After 120 minutes of flow (since the residence time planned for was 120 minutes), the milky white reaction mass reached the BPR; through which it got collected into the collector vessel attached with the BPR.

[0053] Further, this reaction mass post reaction was collected externally into a glass bottle by intermittently releasing the pressure very slowly in order to collect the product without spraying it all over due to the gush of pressure release. This reaction mass visibly was much particulate as compared to the homogeneous emulsion that was the precursor; indicating that nanoparticles have formed. This mixture was allowed to phase separate naturally for a period of 10-15 minutes following which the upper organic layer was decanted away as much as possible leaving behind the denser aqueous part with nanoparticles. This was washed with ethanol and distilled water each thrice by centrifugation at around 8,000-10,000 rpm for 15-20 minutes until all the unreacted matter got eliminated away. The white solid obtained finally after all washings was allowed to air-dry overnight at 80°C. This dried product was further calcined at 550°C for 6 hours at a ramp-rate of 5°C/minute in order to burn off the excess surfactant. The final white product obtained is the desired nanospheres of silica (KCC-1); which was sampled for yield, morphological characterization through microscopy and surface area measurements.

[0054] KCC-1 (fibrous nanospheres of silica) is a very recently explored area in the vast domain of silica based catalysts that have dominated the field of heterogeneous catalytic materials since long. The present invention discloses synthesis of KCC-1 through continuous flow; which can be further employed as a catalytic support. The main advantage of the present invention is that it is practically much less tedious and time-consuming than what has been reported till date; and a reduction in time by more than half has been obtained. Moreover, it has also been demonstrated through this invention that the emulsion known till date as the most important pre-requisite for this synthesis is actually not a pre-requisite at all; and the same product could be obtained through individual pumping of the liquids too. The morphology of the product obtained through this novel methodology is comparable to the conventionally reported batch method.

[0055] The advantages obtained by using the synthesis process can be summarized as follows:
a. Being safe, economically viable and scalable continuous flow process.
b. Decrease in reaction time by more than half of what is reported earlier.
c. Fewer steps are required, because individual reagent solutions (and not an emulsion) could also yield similar product with comparable morphological characteristics.
d. This particular continuous flow reaction is a simple loop reactor which is the most basic form of flow reactor assembly.

[0056] The most important disadvantage that prevailed in the conventional mode of synthesis (batch method) is that it is not scalable i.e. it is not possible to extract more quantities of product that what is possible from a reaction loaded at a particular time in a 1 Liter Microwave reactor, autoclave vessel, or round-bottom flask. The problem solution approach provided by the present invention is scalability, wherein it is possible to scale the reaction i.e. the synthesis could be kept going on and on till the reagent solution(s) are pumped into the flow reactor, depicting a ‘continuous stream of flow’ of product. This is of exemplary value when it comes to the commercial application of the present invention. Synthesis of these extremely attractive catalyst-support molecules through continuous flow hence, proves to be tremendous valuable when extrapolated to the industrial viability of the process.

[0057] This synthesis process disclosed by the present invention is currently being tried on higher and automated models of continuous flow reactors like the Phoenix, etc. which are capable of handling very high temperature and pressure conditions. The experimental analysis and morphological results indicates that the economic potential is significant. Chemical industries dealing in development and applications of supported catalysts will be potential targets for this technology.

[0058] The above description along with the accompanying drawings is intended to describe the preferred embodiments of the invention in sufficient detail to enable those skilled in the art to practice the invention. The above description is intended to be illustrative and should not be interpreted as limiting the scope of the invention. Those skilled in the art to which the invention relates will appreciate that many variations of the described example implementations and other implementations exist within the scope of the claimed invention.
,CLAIMS:We Claim:

1. A system for synthesizing fibrous nanospheres of silica (KCC-1), the system comprising:
a stirrer (1) receiving an emulsion solution for stirring;
at least one pump (2) connected with the stirrer (1), receiving the stirred emulsion;
at least one tubular reactor coil (4) placed inside a temperature controller (5), wherein the temperature controller (5) is connected with the at least one pump (2) for supplying the emulsion or individual reagents separately, into the tubular reactor coil (4);
a back pressure regulator (6) connected with the temperature controller (5)to provide a streamlined and continuous flow of a reacted mixture obtained through a reaction of a reacting mixture at the tubular reactor coil (4),wherein the reacted mixture is centrifuged and calcinated calcined at the back pressure regulator (6) to generate fibrous nanospheres of silica (KCC-1).

2. The system as claimed in claim 1 further comprising at least one junction (9) connecting at least one pump (2) and the tubular reactor coil (4) placed inside a temperature controller (5).

3. The system as claimed in claim 1 further comprising a collector vessel (7) attached with the back pressure regulator (6) for collecting KCC-1 (fibrous nanospheres of silica) from the back pressure regulator (6).

4. The system as claimed in claim 1, wherein the emulsion is a mixture of two phase solutions comprising an aqueous phase solution and an organic phase solution.

5. The system as claimed in claim 1, wherein the temperature controller (5) comprises a heating device or cooling device.

6. The system as claimed in claim 1, wherein the heating device is one of device selected from an oil-bath, a High-Temperature oven or furnace.

7. A process of synthesizing fibrous nanospheres of silica (KCC-1), the process comprising the steps of:
providing an emulsion for synthesis;
stirring the emulsion using a stirrer;
supplying at least one of the emulsion or individual reagents,separately into a tubular reactor coil (4) placed inside a temperature controller (5), by at least one pump(2), wherein a reaction takes place between a reacting mixture comprising emulsion or individual reagents, in the tubular reactor coil (4);
controlling a temperature of the reaction process, uniformly during the progress of the reaction by the temperature controller (5);
receiving a reacted mixture obtained through the reaction at the tubular reactor coil (4) by a back pressure regulator (6), from the tubular reactor coil (4);
applying a pressure by the back pressure regulator (6), to generate a streamlined and continuous flow of reacted mixture;
collecting the pressurized reacted mixture from an outlet of the back pressure regulator (6); and
centrifuging and calcining the collected reacted mixture at the back pressure regulator (6) to generate fibrous nanospheres of silica (KCC-1).

8. The process as claimed in claim 7, wherein the emulsion or individual reagents are supplied separately into the at least one tubular reactor coil (4) placed inside a temperature controller (5), by two pumps (2a, 2b).

9. The process as claimed in claim 7 further comprising the steps of regulating temperature of the process through the temperature controller (5).

10. The process as claimed in claim 7 further comprising the steps of cooling the reactingmixture by passing the reacting mixture through a series of metal tubes connected together in the temperature controller(5).

11. The process as claimed in claim 7 further comprising the steps of collectingfibrous nanospheres of silica (KCC-1) from the back pressure regulator (6) by a collector vessel (7) attached with the back pressure regulator (6).

12. The process as claimed in claim 7, wherein reaction time is controlled by controlling the flow rate of the reagents supplied by at least one pump.

13. The process as claimed in claim 7, wherein the emulsion comprises a mixture of two phase solutions comprising an aqueous phase solution and an organic phase solution.

14. The process as claimed in claim 13, wherein the aqueous phase solution comprises a hydrolyser and surfactant and the organic phase solution comprises a precursor of silica in an organic solvent.

15. The process as claimed in claim 14, wherein the organic phase solution further comprises a stabilizer.

16. The process as claimed in claim 14, wherein the organic solvent comprises a solvent having high-boiling point.

17. The process as claimed in claim 16, wherein the solvent having high-boiling point is selected from a group comprising Cyclohexane, p-Xylene, Decalin.

18. The process as claimed in claim 13, wherein the aqueous phase solution and the organic phase solutionreagents are supplied separately into a tubular reactor coil (4) placed inside a temperature controller (5), by two pumps (2a, 2b).

19. The process as claimed in claim 7, wherein stoichiometry of the reaction is varied based on size, shape or structure of KCC-1 (fibrous nanospheres of silica).

20. The process as claimed in claim 7, wherein the process is performed at temperatures ranging from 100°C to 300°C by applying the corresponding pressures to the temperature using the back pressure regulator (6).