DESC:FIELD
The present disclosure relates to an apparatus and a process for halogenation of a hydrocarbon.
BACKGROUND
Photochemical reactions are initiated by an irradiation source, wherein the photons emitted from the source decompose a reactant to generate free radicals and yield a desired product.
Conventionally, in photochemical reactions the covalent attachment or bonding of an active functional group with an inert solid surface is carried out under gentle reaction conditions. The photochemical reaction is particularly based on the fact that the compound used in the reaction has at least two functional groups, of which one is essentially a photo-activating group. The photo-activating group is responsible for the photochemical reaction. There are different methods for the activation of inert surfaces. However, the drawbacks associated with the conventional method are such as photo-activating compounds used in the conventional method are expensive or difficult to prepare; swelling agents, dispersing agent and/or chemical initiators may be required; and the method is tedious and time consuming.
Therefore, there is felt a need for an alternate apparatus and an alternate process that mitigates the drawbacks mentioned hereinabove.
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 prior art or to at least provide a useful alternative.
An object of the present disclosure is to provide an alternate apparatus and an alternate process that eliminates the use of swelling agents, dispersing agent and/or chemical initiators.
Another object of the present disclosure is to an alternate apparatus and an alternate process that are efficient.
Yet another object of the present disclosure is to an alternate apparatus and an alternate process that are simple and economical.
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 provides an apparatus for halogenation of a hydrocarbon. The apparatus comprises a reaction vessel; and a structure with a plurality of light emitting devices arrayed thereon. The plurality of light emitting devices are configured to emit light having a wavelength in the range of 250 to 500 nm into the reaction vessel to obtain a halogenated hydrocarbon.
The structure can be disposed within the reaction vessel (20) or the reaction vessel (20) can be disposed within the structure.
The structure can be a hollow structure, and the shape of the structure can be at least one selected from the group consisting of hexagon, tetragon and circular.
The structure comprises an arrangement for cooling the structure.
The plurality of light emitting devices can be arrayed on the interior side or the exterior side of the structure.
The plurality of light emitting devices can be selected from the group consisting of LASER, Organic Electroluminescence material, Inorganic Electroluminescence, Organic Light Emitting Diodes and Inorganic Light emitting Diodes.
The distance of the structure from the exterior side of the reaction vessel is in the range of 0.5 cm to 1 cm, or the distance of the structure from the interior side of the reaction vessel is in the range of 0.1 cm to 0.5 cm.
The reaction vessel can be one of a transparent reaction vessel and a non-transparent reaction vessel.
The reaction vessel includes a centrally mounted stirrer.
The apparatus of the present disclosure is used for chlorination of polyvinyl chloride to obtain chlorinated polyvinyl chloride.
The present disclosure also provides a process for halogenation of a hydrocarbon. The process comprises introducing the hydrocarbon in a reaction vessel in the form of a slurry or a solution, followed by heating the hydrocarbon at a temperature in the range of 60°C to 80°C. A halogen is introduced in the reaction vessel. Light of wavelength in the range 250 to 500 nm is irradiated, by a plurality of light emitting devices arrayed on a structure, into the reaction vessel for a time period in the range of 3 hours to 7 hours to obtain a halogenated hydrocarbon.
The process is carried out in inert atmosphere.
The hydrocarbon can be agitated in the reaction vessel while introducing the hydrocarbon in the reaction vessel, and while introducing halogen in the reaction vessel at a speed in the range of 100 rpm to 700 rpm and for a time period in the range of 5 minutes to 60 minutes. The halogen can be chlorine.
The process of the present disclosure is used for chlorination of polyvinyl chloride to obtain chlorinated polyvinyl chloride.
BRIEF DESCRIPTION OF ACCOMPANYING DRAWING
An apparatus and a process for halogenation of a hydrocarbon will now be described with the help of the accompanying drawing, in which:
Figure 1a illustrates a hexagonal structure with a plurality of light emitting devices arrayed on the interior side of the hexagonal structure, in accordance with an embodiment of the present disclosure;
Figure 1b illustrates a tetragonal structure with a plurality of light emitting devices arrayed on the exterior side of the tetragonal structure, in accordance with an embodiment of the present disclosure;
Figure 1c illustrates a circular structure with a plurality of light emitting devices arrayed on the exterior side of the circular structure, in accordance with an embodiment of the present disclosure;
Figure 1d illustrates a hexagonal structure with a plurality of light emitting devices arrayed on the exterior side of the hexagonal structure, in accordance with an embodiment of the present disclosure;
Figure 1e illustrates a hexagonal structure with a plurality of light emitting devices arrayed on the exterior side of the hexagonal structure, wherein the hexagonal structure comprises an arrangement for cooling the hexagonal structure, in accordance with an embodiment of the present disclosure; and
Figure 2 illustrates an apparatus in accordance with an embodiment of the present disclosure.
TABLE ILLUSTRATES A LIST OF THE FOLLOWING REFERENCE NUMERALS:
COMPONENTS REFERENCE NUMERAL
STRUCTURE 10
LIGHT EMITTING DEVICES, LIGHT EMITTING DIODES 12
ARRANGEMENT 14
REACTION VESSEL 20

DETAILED DESCRIPTION
Conventionally, swelling agents, dispersing agent and/or chemical initiators may be required to carry out photochemical reactions. Further, photo-activating compounds, which are expensive and/or difficult to prepare, are required in photochemical reactions, thereby increasing the cost of the entire process. Also, conventionally, UV filament lamps of fixed intensity are used as a light emitting source. These filament lamps are not capable of uniformly distribute light of varying intensity in a reaction vessel. Also, these lamps are ineffective in distributing the light uniformly in a reaction vessel, thereby making the conventional method or source less productive. Moreover, the chlorinated polyvinyl chloride obtained from the conventional process has inherent viscosity of less than 0.80, thermal stability of less than 500 sec and yellowness index greater 3. The lower value of inherent viscosity and thermal stability, and the higher value of yellowness index are not desirable.
The present disclosure, therefore, envisages an apparatus and a process for halogenation of a hydrocarbon that obviates the above mentioned drawbacks.
In one aspect of the present disclosure, there is provided an apparatus for halogenation of a hydrocarbon. The apparatus is described with reference to Figures 1a to 2. The apparatus comprises a reaction vessel (20); and a structure (10) with a plurality of light emitting devices (12) arrayed thereon.
The plurality of light emitting devices (12) are configured to emit the light having a wavelength in the range of 250 to 500 nm into the reaction vessel (20) to obtain a halogenated hydrocarbon. The plurality of light emitting devices (12) are selected from the group consisting of LASER, Organic Electroluminescence material, Inorganic Electroluminescence, Organic Light Emitting Diodes and Inorganic Light emitting Diodes.
The intensity of light or the number of photons emitted from the plurality of light emitting devices (12) arrayed on the structure (10) can be varied or increased by altering the supply of electric power (watts). The light emitted from the plurality of light emitting devices (12) has a narrow spectral width as compared to conventional filament lamps.
The reaction vessel (20) is one of a transparent reaction vessel and a non-transparent reaction vessel. The reaction vessel (20) comprises a centrally mounted stirrer.
The structure (10) is a hollow structure, and the shape of the structure (10) is at least one selected from the group consisting of hexagon, tetragon and circular. The plurality of light emitting devices (12) are arrayed on the interior side or the exterior side of the structure (10). Figures 1a to 2 depict different shapes of the structure (10) with the plurality of light emitting devices (12) arrayed on the interior side or the exterior side of the structure (10).
The structure (10) is disposed within the reaction vessel (20) or the reaction vessel (20) is disposed within the structure (10). In accordance with one embodiment of the present disclosure, the distance of the structure (10) from the exterior side of the reaction vessel (20). In accordance with another embodiment of the present disclosure, the distance of the structure (10) from the interior side of the reaction vessel (20) is in the range of 0.5 cm to 1 cm. Particularly, the structure (10) is either disposed outside or within the reaction vessel (20) in such a way that the light emitted from the plurality of light emitting devices (12) is uniformly distributed in the reaction vessel (20).
In accordance with the present disclosure, for the structure (10) depicted in Figure 1a, the reaction vessel (20) is transparent, and the structure (a hexagonal structure) (10) is disposed outside the reaction vessel (20) (as shown in Figure 2) with the plurality of light emitting devices (12) arrayed on the interior side of the hexagonal structure.
Further, for the structure (10) having different shapes, such as tetragonal, circular and hexagonal, depicted in Figures 1b to 1e, the reaction vessel (20) can be either transparent or non-transparent, and the structure (10) with the plurality of light emitting devices (12) arrayed on the exterior side of the structure (10) can be disposed outside or within the reaction vessel (20).
Different shapes of the structure (10) facilitate uniform distribution of light in the reaction vessel (20). The uniform distribution of light in the reaction vessel (20) enables better interaction of photons with reactants (typically - polyvinyl chloride), thereby facilitating in enhancing the rate of reaction (kinetics) and increasing the productivity, i.e., to obtain the halogenated hydrocarbon (typically – chlorinated polyvinyl chloride (CPVC)) in reduced time as compared to that required in the case of the conventional lamps.
The structure (hexagonal structure) (10) depicted in Figure 1e comprises an arrangement (14) for cooling the structure (10). Particularly, the supply of high electric power to the plurality of light emitting devices (12) for emitting high intensity of light into the reaction vessel (20) results in heating of the structure (10). The arrangement (14) comprises a conduit, wherein the conduit is disposed within the structure (10) so as to form a cavity between the conduit and the structure (10). Typically, nitrogen, water or ethylene glycol solution can be circulated in the cavity, in order to reduce heating of the structure (10).
In another aspect of the present disclosure, there is provided a process for halogenation of a hydrocarbon. The process is described herein below.
The hydrocarbon is introduced into the reaction vessel (20) in the form of a slurry or a solution, followed by heating the hydrocarbon at a temperature in the range of 60°C to 80°C. In accordance with an embodiment of the present disclosure, the hydrocarbon is heated at 70°C. A halogen is introduced into the reaction vessel (20).
In accordance with an embodiment of the present disclosure, the hydrocarbon, in the initial process step and at the time of introducing the halogen in the reaction vessel (20), is agitated by the centrally mounted stirrer at a speed in the range of 100 rpm to 700 rpm for a time period in the range of 5 minutes to 60 minutes.
Light having a wavelength in the range 250 to 500 nm is irradiated, by the plurality of light emitting devices (12) arrayed on the structure (10), into the reaction vessel (20) for a time period in the range of 3 hours to 7 hours to obtain a halogenated hydrocarbon.
The process step of halogenation (typically – chlorination) is carried out under inert atmosphere.
The apparatus and the process of the present disclosure are used for chlorination of polyvinyl chloride to obtain chlorinated polyvinyl chloride. The chlorinated polyvinyl chloride produced in accordance with the present disclosure has viscosity of greater than 0.80, thermal stability of greater than 500 sec and yellowness index less than 3. This indicates that the chlorinated polymer with improved properties such as improved inherent viscosity, improved thermal stability and lower yellowness index are obtained using the apparatus and process of the present disclosure as compared to that obtained using conventional processes.
The present disclosure is further described in light of the following laboratory scale and pilot scale experiments which are set forth for illustration purpose only and not to be construed for limiting the scope of the disclosure. These laboratory scale and pilot scale experiments can be scaled up to industrial/commercial scale and the results obtained can be extrapolated to industrial/commercial scale.
Experimental Details
Experiment 1:
1010 g of aqueous PVC slurry containing 160 g of PVC was taken in a transparent reaction vessel. Subsequently, the slurry was agitated at a speed of 200 revolutions per minute (rpm) for an initial time period of 5 minutes while nitrogen gas was purged inside the reaction vessel through the slurry. In order to remove air or oxygen from the reaction vessel and the slurry, the speed of rotation was then increased to 650 rpm and nitrogen purging was continued for another 40 minutes. At the time of agitation, temperature of 70° C was maintained in the transparent reaction vessel under inert atmosphere. Subsequently, nitrogen purging was stopped and chlorine was then purged through the slurry while maintaining the same conditions (agitation speed and time period of agitation).
The structure (10) depicted in Figure 1a was used for irradiating the transparent reaction vessel with light. Particularly, the transparent reaction vessel was disposed within the structure (10) (i.e., a hexagonal structure with the plurality of LEDs arrayed on the interior side of the structure (10)). The light having a wavelength in the range of 250 nm to 500 nm was incident into the transparent reaction vessel when the transparent reaction vessel and the slurry were found to be saturated with chlorine. The initial time of the reaction was noted from the time at which the contents of the transparent reaction vessel were exposed to the light. The temperature of 70° C was maintained in the transparent reaction vessel before switching off the LED light.
After exposing the transparent reaction vessel to light for 6 hours, the reaction was stopped by stopping the purging of chlorine. Subsequently, in order to remove unreacted chlorine from the transparent reaction vessel, nitrogen gas was purged in the transparent reaction vessel for 1 hour. The CPVC slurry thereafter was filtered and washed with 1500 mL water in three parts. The wet cake was dried at 70 °C under the blow of air and CPVC was obtained as a white dry powder.
Chlorine content (by weight) was checked by weight increase with respect to the PVC dry powder.
It was found that using the conventional UV lamp, 67 wt % chlorination of PVC was achieved in 7 hours; however using the structure (10) depicted in Figure 1a, 67 wt % chlorination of PVC was achieved in 6 hours.
Experiment 2:
The present experiment was carried out by maintaining the conditions mentioned in the experiment 1. Instead of the structure (10) depicted in the Figure 1a, the structure (10) (i.e., a tetragonal structure with the plurality of LEDs arrayed on the exterior side of the structure (10)) depicted in the Figure 1b was used for irradiating the transparent reaction vessel with light. The structure (10) was disposed inside the transparent reaction vessel.
The CPVC slurry obtained was thereafter filtered and washed with 1500 mL water in three parts. The wet cake was subjected to vacuum drying at 50°C under nitrogen purging. The dried cake was neutralized using 0.0125 (M) Ca(OH) 2 and 0.1 wt % NaOCl (sodium hypochlorite) solution to obtain a white dry powder of CPVC.
It was found that using the conventional UV lamp, 67 wt % chlorination of PVC was achieved in 7 hours; however using the structure (10) depicted in Figure 1b, 67 wt % chlorination of PVC was achieved in 6.5 hours.
Experiment 3:
The present experiment was carried out by maintaining the conditions mentioned in the experiment 2. Instead of the structure (10) depicted in the Figure 1b, the structure (10) (i.e., a circular structure with the plurality of LEDs arrayed on the exterior side of the structure (10)) depicted in the Figure 1c was used for irradiating the transparent reaction vessel with light. The structure (10) was disposed inside the transparent reaction vessel.
It was found that using the conventional UV lamp, 67 wt % chlorination of PVC was achieved in 7 hours; however using the structure (10) depicted in Figure 1c, 67 wt % chlorination of PVC was achieved in 5 hours.
Experiment 4:
The present experiment was carried out by maintaining the conditions mentioned in the experiment 2. The structure (10) depicted in the Figure 1c was disposed outside the transparent reaction vessel.
It was found that using the conventional UV lamp, 67 wt % chlorination of PVC was achieved in 7 hours; however using the structure (10) depicted in Figure 1c, 67 wt % chlorination of PVC was achieved in 5 hours and 40 minutes.
Experiment 5:
130 kg of PVC was mixed with 720 liters of water to obtain a PVC slurry. The slurry was taken in a transparent reaction vessel. Subsequently, the slurry was agitated at a speed of 100 revolutions per minute (rpm) for an initial time period of 5 minutes while nitrogen gas was purged inside the reaction vessel through the slurry. In order to remove air or oxygen from the reaction vessel and the slurry, the speed of rotation was then increased to 200 rpm and nitrogen purging was continued for another 40 minutes. At the time of agitation, temperature of 70° C was maintained in the transparent reaction vessel under inert atmosphere. Subsequently, nitrogen purging was stopped and chlorine was then purged through the slurry while maintaining the same conditions.
The structure (10) (i.e., a hexagonal structure with the plurality of LEDs arrayed on the exterior side of the structure (10)) depicted in Figure 1d was used for irradiating the transparent reaction vessel with light.
The LED light having a wavelength in the range of 250 nm to 500 nm was incident into the transparent reaction vessel when the transparent reaction vessel and the slurry were found to be saturated with chlorine. The initial time of the reaction was noted from the time at which the contents of the transparent reaction vessel were exposed to the light. The temperature of 70° C was maintained in the transparent reaction vessel before switching off the LED light.
After exposing the transparent reaction vessel to light for 6 hours, the reaction was stopped by stopping the purging of chlorine. Subsequently, in order to remove unreacted chlorine from the transparent reaction vessel, nitrogen gas was purged in the transparent reaction vessel for 1 hour.
The CPVC slurry obtained was thereafter filtered and washed with 1500 mL water in three parts. The wet cake was subjected to vacuum drying at 50°C under nitrogen purging. The dried cake was neutralized using 0.0125 (M) Ca (OH) 2 and 0.1 wt % NaOCl (sodium hypochlorite) solution to obtain a white dry powder of CPVC.
It was found that using the conventional UV lamp, 67 wt % chlorination of PVC was achieved in 7 hours; however using the structure (10) depicted in Figure 1a, 67 wt % chlorination of PVC was achieved in 5.5 hours.
Moreover, different experiments were conducted to obtain CPVC by varying the power (W) of light emitted from the LEDs. The experimental details are summarized in Table 1:
Table 1: Effect of varying power on the reaction time
Sr.
No. water
(L) PVC
(kg) Pressure of chlorine.
(kg/cm2g) Temp.
(°C) Power of
LED (Watt) Rpm Reaction time (hr)
1 720 130 0.9 70 144 200 6.25
2 720 130 0.9 70 216 200 5.16
3 720 130 0.9 70 288 200 4.91
4 720 130 0.9 70 432 200 3.61
5 720 130 0.9 70 648 200 3.33

From Table – 1, it is evident that the time required for 67 wt % chlorination of PVC decreases with increase in the power or intensity of light emitted from the LEDs.
Experiment 6:
The present experiment was carried out by maintaining the conditions mentioned in the experiment 5. Instead of the structure (10) depicted in the Figure 1d, the structure (10) (i.e., a hexagonal structure with the plurality of LEDs arrayed on the exterior side of the structure (10)) depicted in the Figure 1e was used for irradiating the transparent reaction vessel with light. The structure (10) was disposed inside the transparent reaction vessel.
It was found that using the conventional UV lamp, 67 wt % chlorination of PVC was achieved in 7 hours; however using the structure (10) depicted in Figure 1a, 67 wt % chlorination of PVC was achieved in 5.5 hours.
As described herein above, the advantage of using the structure (10) depicted in Figure 1e is that the structure comprises the arrangement (14) for cooling the structure (10).
TECHNICAL ADVANCES AND ECONOMICAL SIGNIFICANCE
The present disclosure described herein above has several technical advantages including, but not limited to, the realization of an apparatus and a process that are capable of:
• uniformly distributing light in the reaction vessel, thereby increasing the kinetics of the reaction and enhancing the productivity of the process;
• reducing the time required for obtaining the desired product (halogenated hydrocarbon) as compared to that required in case of the conventional filament lamp;
• functioning effectively even after varying the power of electric supply; and
• obtaining the desired product having inherent viscosity of greater than 0.80, thermal stability of greater than 500 sec and yellowness index less than 3.
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 invention to achieve one or more of the desired objects or results. While certain embodiments of the inventions have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Variations or modifications to the formulation of this invention, within the scope of the invention, may occur to those skilled in the art upon reviewing the disclosure herein. Such variations or modifications are well within the spirit of this invention.
The numerical values given for various physical parameters, dimensions and quantities are only approximate values and it is envisaged that the values higher than the numerical value assigned to the physical parameters, dimensions and quantities fall within the scope of the invention unless there is a statement in the specification to the contrary.
While considerable emphasis has been placed herein on the specific features of the preferred embodiment, it will be appreciated that many additional features can be added and that many changes can be made in the preferred embodiment without departing from the principles of the disclosure. These and other changes in the preferred embodiment 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. An apparatus for halogenation of a hydrocarbon, said apparatus comprising:
a) a reaction vessel (20); and
b) a structure (10) with a plurality of light emitting devices (12) arrayed thereon, wherein said plurality of light emitting devices (12) are configured to emit light having a wavelength in the range of 250 to 500 nm into said reaction vessel (20) to obtain a halogenated hydrocarbon.
2. An apparatus for halogenation of a hydrocarbon, said apparatus comprising:
c) a reaction vessel (20); and
d) a structure (10) with a plurality of light emitting devices (12) arrayed thereon, wherein said structure (10) is disposed within said reaction vessel (20) or said reaction vessel (20) is disposed within said structure (10), said plurality of light emitting devices (12) are configured to emit light having a wavelength in the range of 250 to 500 nm into said reaction vessel (20) to obtain a halogenated hydrocarbon.
3. The apparatus as claimed in claim 1 or 2 is used for chlorination of polyvinyl chloride to obtain chlorinated polyvinyl chloride.
4. The apparatus as claimed in claim 1 or 2, wherein said structure (10) is a hollow structure.
5. The apparatus as claimed in claim 1 or 2, wherein said structure (10) comprises an arrangement (14) for cooling said structure (10).
6. The apparatus as claimed in claim 1 or 2 or 4, wherein the shape of said structure (10) is at least one selected from the group consisting of hexagon, tetragon and circular.
7. The apparatus as claimed in claim 1 or 2 or 4, wherein said plurality of light emitting devices (12) are arrayed on the interior side or the exterior side of said structure (10).
8. The apparatus as claimed in claim 1 or 2, wherein the distance of said structure (10) from the exterior side of said reaction vessel (20) is in the range of 0.5 cm to 1 cm, or the distance of said structure (10) from the interior side of said reaction vessel (20) is in the range of 0.1 cm to 0.5 cm.
9. The apparatus as claimed in claim 1 or 2, wherein said plurality of light emitting devices (12) are selected from the group consisting of LASER, Organic Electroluminescence material, Inorganic Electroluminescence, Organic Light Emitting Diodes and Inorganic Light emitting Diodes.
10. The apparatus as claimed in claim 1 or 2, wherein said reaction vessel (20) is one of a transparent reaction vessel and a non-transparent reaction vessel.
11. The apparatus as claimed in claim 1 or 2, wherein said reaction vessel (20) comprises a centrally mounted stirrer.
12. A process for halogenation of a hydrocarbon; said process comprising the following steps:
a) introducing the hydrocarbon into a reaction vessel (20) in the form of a slurry or a solution, followed by heating the hydrocarbon at a temperature in the range of 60°C to 80°C;
b) introducing a halogen into said reaction vessel (20); and
c) halogenating the hydrocarbon by irradiating light having a wavelength in the range 250 to 500 nm, by a plurality of light emitting devices (12) arrayed on a structure (10), into said reaction vessel (20) for a time period in the range of 3 hours to 7 hours to obtain a halogenated hydrocarbon.
13. The process as claimed in claim 12 is used for chlorination of polyvinyl chloride to obtain chlorinated polyvinyl chloride.
14. The process as claimed in claim 12, wherein said process is carried out under inert atmosphere.
15. The process as claimed in claim 12, wherein in the process steps a) and c), the hydrocarbon is agitated by a centrally mounted stirrer at a speed in the range of 100 rpm to 700 rpm for a time period in the range of 5 minutes to 60 minutes.