FIELD OF THE INVENTION
The invention relates to an apparatus particularly useful in preparing fluorinated organic compounds.

BACKGROUND OF THE INVENTION
Fluorinated organic compounds are known for their numerous application as refrigerants, heat transfer media, propellants, foaming agents, blowing agents, gaseous dielectrics, sterilants carriers, polymerization media, particulate removal fluids, carrier fluids, buffing abrasive agents, displacement drying agents and power cycle working fluids, chemical intermediates, monomers and the like.
Most of the fluorinated compounds are prepared by multiple steps that involve fluorinating a chlorinated organic compound with a fluorination agent such as hydrogen fluoride in the presence of a fluorination catalyst. These reactions may be conducted in either the liquid or gas phase or a combination of these.
It is pertinent to mention that the catalyst tends to deactivate slowly during the reaction. It is believed that deactivation is the result of either polymerisation leading to the formation of oligomers, polymers, or decomposition which further leads to coking of the catalyst. These oligomers, polymers or decomposition products lead directly to catalyst deactivation. Deactivation of the catalyst compromises yield and creates other economic disadvantages and disruption to the process.
US. patent No. 9,353,029 describes a process for preparation of 1234yf comprising the step of atomizing chlorinated propene/propane using a reactor apparatus wherein the reaction chamber containing catalytic bed in proximity to the heating chamber. It has been found by the present inventor that if heating chamber where vaporization occurs, is in proximity to the reaction chamber, there may be chance that some liquid/solid chlorinated hydrocarbon enters the reaction chambers initiating coking and damage the catalyst.
Therefore, a need exists to extend catalyst life for the fluorination reactions.

SUMMARY OF THE INVENTION
In first aspect, the present invention provides an apparatus that minimizes the undesired side reactions and decomposition.
In second aspect, the present invention provides an apparatus comprising of:
a) a mixing zone and a reaction zone;
b) a chlorinated hydrocarbon is fed as a liquid through a fine nozzle into an injector at an ambient temperature into a mixing zone situated away from the catalyst bed;
c) a superheated anhydrous hydrogen fluoride (AHF) as gaseous stream is fed into the injector through a different nozzle that atomizes the chlorinated hydrocarbon;
e) a mixture of AHF and the chlorinated hydrocarbon is passed through a heat exchanger that lies between the mixing zone and the reaction zone;
f) a mixture of AHF and the chlorinated hydrocarbon after coming out of the heat exchanger had attained ambient reaction temperature and is fed to the reaction zone containing the catalyst bed; This ambient reaction temperature should be more than 10°C above the dew point temperature.

BRIEF DESCRIPTION OF THE FIGURE
Figure 1 depicts an apparatus design of the present invention. It illustrates an apparatus equipped with an injector (A or B), heat exchangers viz., Exchanger-1, Exchanger-2 and Exchanger-3, and a reactor comprising the catalyst.
Figure 2 depicts an apparatus design of the present invention. It illustrates an apparatus equipped with an injector (A or B), heat exchangers viz., Exchanger-1, Exchanger-2 and Exchanger-3 and a reactor comprising the catalyst. This apparatus has an option of recycling the spent gases (1b) along with the fresh raw material (1a).
Figure 3 depicts the design 1 of the injector ‘A’ used in the present invention. It illustrates an injector ‘A’ as a perforated pipe installed in static mixer. There are perforations on the entire circumference of pipe. The N1 and N2 are entrance nozzles for fluids, N3 flange of the injector and N4 is exit nozzle. The perforations are at 90°C angle to each other.
Figure 4 depicts the design 2 of the injector ‘B’ used in the present invention. It illustrates an injector ‘B’ as perforated plate installed between flanges in pipe. The perforations are of size preferably less than 3mm.

DETAILED DESCRIPTION OF THE INVENTION
As used herein, “Dew point temperature” can be defined as the temperature at which first drop of mixture starts to condenser at particular pressure.
As used herein, the ambient temperature is the reaction temperature that is ideally 20°C above the vaporisation temperature of mixture to avoid liquid carryover in reactor catalyst bed. Liquid is detrimental for catalyst.
As used herein, “injector A” refers to an injector or an atomizer having a perforated pipe installed in static mixer. Perforated pipes have multiple perforations of size 0.1 mm to 20 mm, preferably of 2 mm to 5 mm and more preferably of 3mm. Very small size holes below 0.1mm can create high pressure drop or can choke holes. The injector is made of an exotic alloy of Nickel, Copper, Chromium, Zinc, Molybdenum, Silica, and Manganese. Examples of alloys includes Monel, Inconel Hastelloy, Stainless steel, Incoloy or the like. Advantage of these design is better uniform mixing, heat dissipation and low pressure drop.
As used herein, “injector B” refers to an injector or an atomizer having perforated plate installed between flanges in pipe. There are perforations on the entire circumference of pipe. The injector is made of an exotic alloy of Nickel, Copper, Chromium, Zinc, Molybdenum, Silica, and Manganese. Examples of alloys includes Monel, Inconel Hastelloy, Stainless steel, Incoloy or the like.
In first embodiment, the present invention enables preparation of fluorinated saturated hydrocarbons such as 244bb, 245eb, 254eb, 245cb, 244eb, 152a.
In another embodiment, the present invention enables preparation of unsaturated fluorinated hydrocarbons such as 1234yf, 1234ze, 1233xf, 1233zd, 1225ye, 1336mzz or the like
In another embodiment, the chlorinated/ chloroflourinated hydrocarbon are selected from the group consisting of 244cb, 244bb, 1230xa, 244eb, 1233xf, 1233zd, 240fa, 240db,243db, 244bb, 253fb, 1232xf, 1240zf, 1240za, 1230yf, 1223xd, 1231xa, ethylene dichloride, vinylchloride or a mixtures thereof.
In another embodiment of the present invention, the atomized organic feed mixed with superheated AHF, is fed in a parabolic/ hyperbolic form.
In another embodiment, the apparatus of the present invention has a mixing chamber and a reaction chamber, wherein the reaction chamber consists of a catalytic bed and wherein there is a heat exchanger in between the reaction chamber and the mixing chamber. The heat exchanger ensures that the atomised mist comprising chlorinated / chloroflourinated hydrocarbon and AHF attains an ambient temperature before entering the catalytic bed of the reaction chamber.
The heat exchanger enables the atomised mist comprising chlorinated/ chloroflourinated hydrocarbon and AHF to attain an ambient temperature to prevent any liquid or solid carryover to enter the catalyst bed of the reaction chamber. Thus prevents the formation of coke/oligomers and extends the life of the catalyst. Injector enables complete fine vaporisation of chlorinated/fluorinated organic and depress boiling point of mixture to prevent decomposition of organic, solid carryover to enter the catalyst bed of reaction chamber. It also improves operational efficiency of the process.
In another embodiments, the present invention is carried out under conditions effective to provide conversion of at least about 40%, more preferably at least about 55%, and even more preferably at least about 70%. In certain preferred embodiments the conversion is at least about 90%, and more preferably about 100%.
The fluorination reaction may be conducted in any reactor suitable for a vapour or liquid phase fluorination reaction. Examples of suitable reactor includes vapour phase Isothermal, Adiabatic, Loop reactor, Fluidised bed reactor and for liquid phase batch/semibatch/CSTR reactor with/without agitation. Preferably the reactor is constructed from materials which are resistant to the corrosive effects of hydrogen fluoride and catalyst such as Hastelloy, Inconel, Monel and vessels lined with fluoropolymers. In case of a vapour phase process, the reactor is filled with a vapour phase fluorination catalyst.
The fluorination catalysts known in the art may be used in this process. Suitable catalysts include, but are not limited to chromium, aluminium, cobalt, manganese, nickel and iron oxides, hydroxides, halides, oxyhalides, inorganic salts thereof and their mixtures. Combinations of catalysts suitable for the present invention nonexclusively include Cr2O3, FeCl3/C, Cr2O3/Al2O3, Cr2O3/AlF3, Cr2O3/carbon, CoCl2/Cr2O3/Al2O3, NiCl2/Cr2O3/Al2O3, CoCl2/AlF3, NiCl2/AlF3 and mixtures thereof. Chromium oxide/ aluminium oxide catalysts are described in U.S. Pat. No. 5,155,082 which is incorporated herein by reference. Chromium (III) oxides such as crystalline chromium oxide or amorphous chromium oxide are preferred with amorphous chromium oxide being most preferred. Chromium oxide (Cr2O3) is a commercially available material which may be purchased in a variety of particle sizes. Fluorination catalysts having a purity of at least 98% are preferred. The fluorination catalyst is present in an excess or in at least an amount sufficient to drive the reaction.
In another embodiment the HF is pre-vaporized or preheated to a temperature of from about 180°C to about 350°C (superheated) prior to entering the reactor.
In another embodiment, the chlorinated hydrocarbon is vaporized after being atomized or made into a fine mist/dispersion by use of an injector.
In another embodiment, the present invention uses injector of design 1
In another embodiment, the present invention uses injector of design 2.
The reactor can be isothermal or adiabatic.
Anhydrous HF and the chlorinated hydrocarbon feeds are adjusted to the desired mole ratio. The HF to chlorinated hydrocarbon mole ratio preferably ranges from about 3:1 to about 100:1; more preferably from about 4:1 to about 50:1 and most preferably from about 5:1 to about 20:1.
The vapour phase fluorination reaction is conducted at a preferred temperature range of about 80? to about 400°C; more preferably from about 100°C to about 350°C and most preferably from about 200°C to about 330°C.
Reactor pressure is not critical and can be super atmospheric, atmospheric or under vacuum. The vacuum pressure can be from about 5 torr to about 760 torr. During the vapour phase fluorination reaction, chlorinated hydrocarbon and HF are reacted in a vapour phase in the presence of the fluorination catalyst.
The reactant vapour is allowed to contact the fluorination catalyst in about 1 to 120 seconds or more preferably in about 1 to 20 seconds.
The process flow is in the downward direction through a bed of the catalyst. Before each use, the catalyst is preferably dried, pre-treated and activated. It may also be advantageous to periodically regenerate the catalyst after prolonged use while in place in the reactor. Pre-treatment can be done by heating the catalyst to about 250° C. to about 430° C. in a stream of nitrogen or other inert gas. The catalyst may then be activated by treating it with a stream of HF diluted with a large excess of nitrogen gas in order to obtain high catalyst activity. Regeneration of the catalyst may be accomplished by any means known in the art such as, for example, by passing air or air diluted with nitrogen over the catalyst at temperatures of from about 100°C to about 400°C, preferably from about 200°C to about 375°C, for from about 8 hours to about 3 days, depending on the size of the reactor.
In another embodiment, the present invention may be employed, for example, as part of a larger process for preparation of 2,3,3,3-tetrafluoropropene (1234yf) wherein starting material for this process is one or more chlorinated / chloroflourinated hydrocarbon according to Formulae I, II and/or III:
CX2-CCl—CH2X (Formula I)
CX3—CCl-CH2 (Formula II)
CX3—CHCl—CH2X (Formula III)
wherein X is independently selected from F, Cl, Br, and I, provided that at least one X is not fluorine; Preferably, these compounds contain at least one chlorine, more preferably a majority of X is chlorine, and even more preferably all X is chlorine.
Thus, it is contemplated that the present reaction may be performed using a wide variety of process parameters and process conditions in view of the overall teachings contained herein. However, it is preferred in certain embodiments that this reaction step comprises a gas phase reaction, preferably in the presence of catalyst.

EXAMPLES
Example 1:
Referring to the Figure 1, which depicts a preferred apparatus of the invention,
AHF is vaporized and superheated in an exchanger-2 to a temperature of 200-300oC at 5 to 15 barg and then passed to an injector A/B. R-1230xa is preheated to a temperature of 120 -170oC at 5 -15 barg and then passed to an injector-A/B, where the liquid is dispersed into fine droplets and vaporized by the heat of AHF. The molar ratio of AHF: Organic is 10:1 to 20:1. After this the vaporized mixture is superheated to the required reaction temperature by Exchanger-3 and then passed into the fixed bed catalytic reactor. Reaction temperature to be greater than 20°C from the vaporization temperature to prevent any liquid or solid carryover to the catalyst bed. The liquid and solid going into the reactor may permanently damage the catalyst. As the molar ratio of AHF is high, it helps in decreasing the boiling point of R-1230xa and AHF mixture. For example at 10 barg the boiling point of AHF and R-1230xa mixture with a molar ratio of 15:1 is 162°C. This method of vaporizing helps prevent formation of coke/ oligomers in the vaporization section and helps in getting a better catalyst life.
During the course of the reaction, the reaction temperature is increased from 170°C to 320°C as the activity of the catalyst come down. As the reaction temperature increases, the superheater (Exchanger-3) is used to help the feed stream achieve the reaction temperature. Also there is flexibility of changing operating pressure of reaction. In the absence of super-heater, to achieve the reaction temperature, higher molar ratio of AHF pass through injector leading to high AHF recycle adding to very high operating costs.
Example 2:
Referring to the Figure 2, which depicts another preferred apparatus of the invention, AHF is vaporized and superheated in Exchanger-2 to a temperature of 200 -300°C at 5 to 15 barg and then passed to injector A/B. Organic feed R1230xa through (1a) and/or mixture of R1230xa/R1233xf/R244bb through (1b) to be passed through perforated injector A/B where it is atomized and vaporized by superheated AHF entering in static mixer. The reaction is performed as in example 1.
Advantage of these design is better uniform mixing, heat dissipation and low pressure drop.
It has been found that the present invention results in a significant increase to the longevity of the catalyst, e.g. the vapour phase fluorination catalyst, preferably by at least 20%, more preferably by at least 40%. It is believed that the present invention substantially prevents the undesirable polymerization and/or decomposition of the starting materials that form a layer of coke on the catalyst surface.
The reaction temperature is preferably about 300-550°C and the reaction pressure is preferably about 0-10 barg. Preferably, the reactor effluent is fed to a caustic scrubber or to a distillation column to remove the by-product of hydrochloric acid to produce an acid-free organic product which, optionally, may undergo further purification.

CLAIMS:WE CLAIMS:
1. A process for preparation of fluorinated hydrocarbon comprising of:
a) an apparatus equipped with a mixing zone and a reaction zone;
b) a chlorinated hydrocarbon is fed as a liquid through a fine nozzle of an injector at an ambient temperature into a mixing zone situated away from the catalyst bed;
c) a superheated anhydrous hydrogen fluoride (AHF) as gaseous stream is fed into the mixing zone by a different nozzle of the injector;
d) a mixture of AHF and the chlorinated hydrocarbon is passed through a heat exchanger that lies between the mixing zone and the reaction zone; and
e) a mixture of AHF and the chlorinated hydrocarbon after coming out of the heat exchanger is fed to the reaction zone containing the catalyst bed,
wherein, the ambient reaction temperature is more than 10°C above the dew point temperature.
2. The apparatus as claimed in claim 1, wherein the apparatus design is depicted in Figures 1 to 4.
3. The apparatus as claimed in claim 1, wherein the injector is selected from “injector A” or “injector B”.
4. The apparatus as claimed in claims 1 and 3, wherein the “injector A” refers to an injector or an atomizer having a perforated pipe installed in static mixer.
5. The apparatus as claimed in claims 1 and 3, wherein the “injector B” refers to an injector or an atomizer having perforated plate installed between flanges in pipe.
6. The apparatus as claimed in claim 1, wherein the chlorinated hydrocarbon is selected from a group consisting of 244cb, 244bb, 1230xa, 244eb, 1233xf, 1233zd, 240fa, 240db,243db, 244bb, 253fb, 1232xf, 1240zf, 1240za, 1230yf, 1223xd, 1231xa, ethylene dichloride and vinyl chloride or a mixtures thereof.
7. The apparatus as claimed in claim 1, wherein the catalyst is selected from a group consisting of chromium, aluminium, cobalt, manganese, nickel, iron oxides, hydroxides, halides, oxyhalides and inorganic salts or a mixtures thereof.
8. The apparatus as claimed in claim 1, wherein the fluorinated hydrocarbons are selected from a group consisting of 244bb, 245eb, 254eb, 245cb, 244eb, 152a, 1234yf, 1234ze, 1233xf, 1233zd, 1225ye, 1336mzz and the like.
9. The apparatus as claimed in claim 1, wherein 2,3,3,3-tetrafluoropropene (1234yf) is prepared by using one or more chlorinated / chloroflourinated hydrocarbon according to Formulae I, II and/or III:
CX2-CCl—CH2X (Formula I)
CX3—CCl-CH2 (Formula II)
CX3—CHCl—CH2X (Formula III)
wherein X is independently selected from F, Cl, Br, and I, provided that at least one X is not fluorine; Preferably, these compounds contain at least one chlorine, more preferably a majority of X is chlorine, and even more preferably all X is chlorine.