Device for thermokinetic property measurement

Abstract

A device which can be used as a flow reactor for synthesis and for discerning the reaction kinetics as well as a flow calorimeter is a need in the art. To fulfill this need, the invention discloses a simple calorimeter that functions as a device to measure reaction kinetics, preferably heat of reaction in a continuous manner, in adiabatic as well as in isothermal conditions. The distinct advantages of the device include online determination of thermokinetic properties, continuous determination of thermokinetic properties and applicable for determination in adiabatic as well as isothermal modes. The device may function independently or may be used in combination with reactors, micro reactors or tubular reactors.

Claims

1. A device for thermokinetic property measurement to measure reaction kinetics in adiabatic as well as in isothermal conditions comprising a data management system being connected to a continuous flow and a measurement section and a monitoring and processing unit, wherein said continuous flow and the measurement section further comprises a sectionalized jacket, continuous flow sections for a reaction mixture, an assembly of four way thermally resistant connectors for parallel flow of the reaction mixture as well as a thermic fluid, an inlet for a tube carrying the reaction mixture, an outlet for the tube carrying the reaction mixture, an inlet for a thermic fluid, an outlet for the thermic fluid wherein said assembly of four way thermally resistant connectors for parallel flow of the reaction mixture as well as the thermic fluid further comprises four way thermally resistant connectors, a temperature measurement device to measure at least one thermokinetic property of the reaction mixture and cause measurement of reaction-kinetics by the data management system, a sealing section, an outlet for withdrawing at least the reaction mixture samples regulated by a valve.

2. The device as claimed in claim 1, wherein data management system comprises a data acquisition system and a device to analyze generated and acquired data.

3. The device as claimed in claim 1, wherein temperature measurement device used is selected from the group consisting of thermocouples, thermometers and IR sensors.

4. The device as claimed in claim 1, wherein said temperature measurement device is inserted through a tube wall at different spatial locations such that it contacts reaction mixture and thermic fluids flowing through the tube.

5. The device as claimed in claim 1, wherein the continuous flow sections are made out of metals, metal alloys, surface coated metallic tubes, polymeric tubes, and/or quartz tubes.

6. The device as claimed in claim 1, wherein the cross section of the continuous flow sections is circular or a cross-section made of straight edges.

7. The device as claimed in claim 1, wherein said device functions independently, as a standalone device or in combination with reactors, micro reactors or tubular reactors.

8. A method of measuring reaction kinetics, comprising flowing the reaction mixture through the tube of the device as claimed in claim 1, monitoring, during the reaction, a temperature of the tube at different locations, collecting samples at the outlet, and analyzing the samples during and after the reaction.

9. The device as claimed in claim 1, wherein an acquisition of the measured temperature is done by the temperature measurement device through wired or wireless data acquisition system(s), wherein the temperature measurement device is a thermocouple.

10. A method of measuring reaction kinetics, comprising flowing the reaction mixture through the tube of the device as claimed in claim 1, measuring thermokinetic properties of a reaction occurring in the reaction mixture at least through the temperature-measurement device, and determining reaction kinetics of said reaction from said thermokinetic properties at-least based on the data management system.

11. The device of claim 1, wherein said reaction kinetics and heat of reaction are determined during the reaction.

12. The device as claimed in claim 6, wherein said cross section made of straight edges is selected from the group consisting of triangular, rectangular, pentagonal and hexagonal.

13. The method of claim 8, wherein techniques for analysis during the reaction are selected from the group consisting of UV-Vis Spectrophotometry and IR Spectroscopy.

14. The method of claim 8, wherein techniques for analysis after the reaction are selected from the group consisting of Gas Chromatography, high performance liquid chromatography (HPLC), ultra performance liquid chromatography (UPLC), and mass spectrophotometry (MS).

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) FIG. 1 represents schematic of the device (1) showing the assembly of thermokinetic property measurement system comprising of data. management system (2), the continuous flow and measurement section (3) and the monitoring and processing unit (4).

(2) FIG. 2 represents the details of the the continuous flow and measurement section (3) comprising of a sectionalized jacket made from thermally resistant material (301), the continuous flow sections for reaction mixture (304), assembly of four way thermally resistant connectors (305) for parallel flow of reaction mixture as well as the thermic fluid, inlet for the tube (307) carrying the reacting fluid, outlet for the tube (306) carrying the reacting fluid, inlet for the thermic fluid (302), outlet for the thermic fluid (303).

(3) FIG. 3 represents the assembly of the four way thermally resistant connectors (305) for parallel flow of reaction mixture as well as the thermic fluid comprises of four way thermally resistant connectors (506), a thermocouple (501), a sealing section (502), outlet for withdrawing samples (504) regulated by a valve (503) for straight as well as coiled segment (304).

(4) FIG. 4 shows the details of the four way thermally resistant connector (506) facilitated with threaded or tapered sleeves (603) for connecting to jacket (305) and a set of end to end bores (601) for flowing the thermic fluid from one jacket section to the next and the bore to flow the reactants through the reaction tubes (602) and a bore connecting the section carrying the reacting fluids to the sampling port (604).

DETAILED DESCRIPTION OF THE INVENTION

(5) The present invention brings out a device which can be used as a flow reactor for synthesis and for discerning the reaction kinetics as well as a flow calorimeter. The device can be used independently for each of the above or simultaneously for any two or all of them together.

(6) A calorimeter that functions as a device to measure reaction kinetics, preferably heat of reaction in a continuous manner, in adiabatic as well as in isothermal conditions comprising a data acquisition system (2), continuous flow and measurement section (3) and monitoring and processing unit (4), said continuous flow and measurement section comprising a sectionalized jacket made from thermally resistant material (301), the continuous flow sections for reaction mixture (304), assembly of four way thermally resistant connectors for parallel flow of reaction mixture as well as thermic fluid (305), inlet for the tube carrying the reacting fluid (307), outlet for the tube carrying the reacting fluid (306), inlet for the thermic fluid (302), outlet for the thermic fluid (303) is disclosed herein.

(7) The invention discloses a calorimeter that functions as a device to measure reaction kinetics, preferably heat of reaction/dilution/dissolution/quenching etc. with or without phase change in a continuous manner, in adiabatic as well as in isothermal conditions comprising data acquisition system (2), continuous flow and measurement section (3) and monitoring and processing unit (4), said continuous flow and measurement section comprising a sectionalized jacket made from thermally resistant material (301), the continuous flow sections for reaction mixture (304), assembly of four way thermally resistant connectors for parallel flow of reaction mixture as well as thermic fluid (305), inlet for the tube carrying the reacting fluid (307), outlet for the tube carrying the reacting fluid (306), inlet for the thermic fluid (302) and outlet for the thermic fluid (303).

(8) The invention discloses a device for measurement of thermo kinetic properties comprising a tube (304) attached to the inlet of the thermostatic fluid of the reactor, a tube attached to the outlet of the fluid, at least one sampling port with a thermometer sensing device (viz. thermocouples, thermometers, IR probes) and a data management system to manage the temperature measurement and data generated by the device. The data management system further comprises a data acquisition system and a device, which uses the local temperature vs. time data for exploring the steady state features for reliable estimation of the heat of reaction, continuously. The spatiotemporal temperature data upon achieving the steady state was integrated over length and combined with the local composition using equation 2 to analyse the generated and acquired data. (refer FIG. 1).

(9) Temperature data acquisition system (2) that uses the inputs from thermocouples in terms of electric signal is converted in the form of temperature.

(10) The assembly of four way thermally resistant connectors (305) for parallel flow of reaction mixture as well as thermic fluid comprises four way thermally resistant connectors (506) for parallel flow of reaction mixture as well as the thermic fluid (305) comprising of a thermocouple (501), a sealing section (502), outlet for withdrawing samples (504) regulated by a valve (503) for straight as well as coiled (304) segment.

(11) The enthalpies were estimated from the energy conservation in the system. Since the system can be maintained adiabatic as well as isothermal the energy conservation can be used to estimate the heat of dilution, dissolution, reaction etc. depending upon the mode of operation. For the case where the system is completely insulated, the reaction will take place at nearly adiabatic condition. The heat released from the reaction is transformed to the thermal energy thereby increasing the temperature of the reaction system. Since the tube material as well as the insulating material would have some heat capacity, there will be a finite loss of heat to them during the operation. These issues can be taken into account to establish a complete heat balance in the reactor system.

(12) The device (with reference to FIG. 2) comprises of a tube (304) (having circular cross-section or cross-section made of straight edges viz. triangular, rectangular, pentagonal and hexagonal etc.) of any material (metal, alloys, polymeric, polymer composites, ceramic etc.) either in straight form of helical coil or spiral shape. Temperature measurement device (thermocouples, thermometers, IR probes) is inserted through the tube wall at different spatial locations such that they touch the fluids flowing through the tube. The locations of insert are made leak proof by using leak proof sealing. At the points of insert the tube has a port, which can act as an outlet or sampling port using a On-Off valve. The reacting/dissolving mixture enters the tube at the inlet. The fluids can be injected using any suitable dosing system viz. syringe pump for dosing liquid and a mass flow controlled gas supply from a gas cylinder.

(13) The temperature at different locations was monitored online. The other ports at the locations where the local temperature is measured are used for taking the local reaction mixture sample to measure the composition. The extent of conversion or dissolution could be measured. This can be clone online using an online UV-Vis spectrophotometer or off-line sample analysis.

(14) The following set of equations are used for the estimation of local enthalpy

(15) $H_r=\frac{Q_L+H}{n}$
Where QL is the thermal loss in the system, H is the enthalpy rise in the system due to chemical/physical transformation and n is the number of moles. H is estimated as

(16) $H={}_{T_{in}}^{T_{max}}{}_i{m}_{i}C{p}_{i}dT$
where m.sub.i is mass flow rate of materials, Cp.sub.i is the specific heat capacity.

(17) The device of the invention for measuring thermo kinetic properties functions independently, as a standalone device.

(18) The device functions in combination with reactors, micro reactors or tubular reactors. Device may be connected to systems that function as reactors and also provide data with regard to various reaction parameters.

EXAMPLES

(19) Following examples are given by way of illustration therefore should not be construed to limit the scope of the invention.

Example 1

(20) The flow reaction calorimeter comprised of sections of specific length of polytetrafluoroethylene (PTFE) tubes connected to four-way connectors. While two opposite ports of the four-way connectors were used for connecting the tube, the other two opposite ports were connected to thermocouple and to the sample withdrawal section, respectively. Four such ports were used to measure the local temperature at four different locations along the length of tube. Water and concentrated sulfuric acid were dosed independently using syringe pumps. Residence time of liquids was varied in the range of 60 s to 300 s for the total volume of 1.4 ml of the tubular reactor. The entire system was insulated to avoid any heat loss. The losses were estimated using hot water at different flow rates and temperatures. Initial fluid temperature was 27 C. For a residence time of 60 s, the temperature at first thermocouple resulted in 114.2 C. while the temperature at the second and third thermocouple showed temperature of 102.3 C. and 70.6 C., respectively. From the data of mass flow rates, temperature difference and the estimated thermal loss the value of heat of dissolution was estimated and was 451.83 J/g.

Example 2

(21) For the set-up explained in Example 1, when equal moles of sulfuric acid and sodium hydroxide were pumped separately and mixed, the temperature at the mixing point, the thermocouple alter 23 cm and 78 cm respectively rises to 31.8 C., 37.3 C. and 37.6 C., respectively. The estimated heat of neutralization comes to 59.42 J/g (1.67%).

Example 3

(22) For the set-up explained in Example 1, when equal moles of nitrating mixture and bromobenzene in acetic acid were pumped separately and mixed. The estimated heat of neutralization comes to 86.73 kJ/mol.

Example 4

(23) For the set-up explained in Example 1, when equal moles of fuming nitric acid and acetophenone were pumped separately and mixed to react. The estimated heat of neutralization comes to 137 kJ/mol. With nitrating mixture the value comes to 189 kJ/mol.

Example 5

(24) The flow reaction calorimeter comprised of sections of specific length of stainless steel (SS316) tubes connected to PTFE (polytetrafluoroethylene) four-way connectors having independent and parallel bores for flow of reacting fluids and the heat transfer fluid. Remaining two bores acted as ports for thermocouple and to the sample withdrawal section, respectively. Four such ports were used to measure the local temperature at four different locations along the length of tube. Fuming nitric acid and water were passed through the inlet of reacting channel [104] while water at ambient condition was used as the heat transfer fluid flowing through the jacket [305] made out of a thermally resistant material. At steady state, temperature was measured at different ports and samples were withdrawn to check the extent of dilution. Residence time of liquids was varied in the range of 20 s to 60 s for the total volume of 28 ml of the tubular reactor. The rise in the temperature in the water through jacket was monitored and used for the estimation of losses. Inlet fluid temperature was 25 C. For a residence time of 15 s, 30 s, 45 s and 60 s, the temperature at the respective thermocouples resulted in steady state values of 34 C., 46 C., 29 C. and 26 C., respectively. The extent of dilution at different residence times varied as 56%, 75%, 89% and 100%, respectively. From the data of mass flow rates, temperature difference and the estimated thermal loss the value of heat of dissolution was estimated and was 114.9 kJ/kg.

Example 6

(25) Using the system described in Example 5 with a PTFE tube for flowing the reaction mixture, the apparatus was used for the measurement of heat of reaction between sodium hydroxide and ethyl acetate. Temperature of the reactants at the inlet was 20 C. and the residence time in the device was 10 minutes. At steady state, temperature was measured at different ports and samples were withdrawn to check the reaction progress. The jacket was kept empty and was connected to vacuum line to avoid any losses and operate the system at adiabatic condition. Samples were withdrawn from different outlets and analyzed. The temperature data at each position was monitored and used for the estimation of heat of reaction. The known value of the heat of reaction for this system is 73.9 kJ/mol. With reaction remaining incomplete event at the final outlet, the estimated heat of reaction based on the temperature rise alone (and the specific heat capacities of the reactants) varied between 77% to 85% of the known data depending upon the location of temperature data. Upon estimating the heat of reaction by knowing the exact composition of the reaction mixture at the point of temperature measurement, the estimated values varied in the range of 97-98.5% of the known values.

Advantages of the Invention

(26) 1. Online determination of thereto kinetic properties possible.

(27) 2. Continuous determination of thermo kinetic properties possible.

(28) 3. Applicable for determination in adiabatic as well as isothermal modes.