CN103702988A - Fluorinated oxiranes as organic rankine cycle working fluids and methods of using same - Google Patents

Abstract

A process and an apparatus for converting thermal energy into mechanical energy in a Rankine cycle are provided. The process and apparatus include a working fluid that comprises a fluorinated oxirane. The fluorinated oxirane can contain substantially no hydrogen atoms bonded to carbon atoms and can have from about 4 to about 9 carbon atoms. The process can drive a turbine and, in some embodiments, generate electricity.

Description

Fluorinated epoxies as organic rankine cycle working fluids and methods of using same

technical field

The present invention relates to the use of fluorinated epoxies as Rankine cycle working fluids.

Background technique

Rankine cycle systems are often used to generate electrical energy, which can then be provided to an electrical distribution system, or to an electrical grid for residential and commercial use. Electrical energy is generated by converting thermal energy into mechanical energy and then converting the mechanical energy into electrical energy. Closed Rankine systems are known and include: a heat source, such as a boiler or evaporator of the motive fluid (working fluid); a turbine, which is fed from the boiler to drive a generator or other load; exhaust steam from the turbine; and means to draw recirculated condensed fluid back to the heat source. US Patent No. 3,393,515 (Tabor et al.) describes a self-starting power generation unit operating on a closed Rankine cycle. The motive fluid that has been used in such systems is often water. The heat source is any form of fossil fuel such as oil, coal or natural gas.

Organic working fluids can boil at temperatures up to the critical temperature, above which there is no boiling, with higher fluid critical temperatures resulting in higher Rankine cycle efficiencies. Typically, fluids such as 1,1,1,3,3-pentafluoropropane (R245fa refrigerant, available under the trade designation GENETRON from Honeywell, Morristown, NJ) have been For use in Rankine cycle systems. Recently, other perfluorinated ketones with higher critical temperatures than R245fa (critical temperature of 150° C.) have been considered for use in Rankine cycle devices because these materials have higher critical temperatures than R245fa. For example, US Patent No. 7,100,380 (Brasz et al.) discloses organic Rankine cycle systems using other perfluorinated ketones with higher thermodynamic Rankine cycle efficiencies than R245fa. For example, Brasz et al. disclose the use of _CF3CF2C (O)CF( _CF3 ) ₂ and other _related compounds as Rankine working fluids.

The use of fluorinated oxiranes for fire extinguishing has been disclosed, for example, in the document entitled "Fluorinated Oxiranes as Fire Extinguishing Compositions and Methods of Extinguishing Fires Therewith" filed on January 10, 2011 Chemicals and methods of extinguishing fires therewith) U.S.S.N. 61/431,119. The use of fluorinated oxiranes as dielectric fluids is disclosed, for example, in U.S.S.N. 61/ 435,867. Lubricants containing fluorinated epoxides are disclosed, for example, in U.S.S.N. 61/448,826, filed March 10, 2011, entitled "Lubricant Compositions Containing Fluorooxiranes" (lubricant compositions containing fluorinated epoxides). The use of fluorinated oxiranes as heat transfer fluids is disclosed in applicant's co-pending patent application entitled "Fluorinated Oxiranes as Heat Transfer Fluids" filed concurrently with this case. Docket No. 67218US002.

Contents of the invention

There is a continuing need for organic Rankine cycle working fluids with higher critical pressures and temperatures and good thermal stability. There is a need for a working fluid that is less harmful to the environment and has acceptable environmental properties and is non-flammable. There is also a need for a working fluid that is more efficient in energy transfer and still usable in systems with simple device designs.

In one aspect, there is provided a method for converting thermal energy to mechanical energy in a Rankine cycle, comprising the steps of vaporizing a working fluid with a heat source to form a vaporized working fluid, expanding the vaporized working fluid through a turbine, using a cooling A source cools the vaporized working fluid to form a condensed working fluid, and pumps the condensed working fluid, wherein the working fluid comprises a fluorinated epoxy. The fluorinated epoxides can be substantially free of hydrogen atoms bonded to carbon atoms and can have a total of about 4 to about 9 carbon atoms. In some embodiments, the fluorinated epoxide may contain 6 carbon atoms. Fluorinated epoxides can have a critical temperature greater than about 150°C.

In another aspect, there is provided a method for recovering waste heat comprising: passing a liquid working fluid through a heat exchanger in communication with a method of generating waste heat to produce a vaporized working fluid, removing the vaporized working fluid from the heat exchanger A fluid that passes a vaporized working fluid through an expander, wherein the waste heat is converted to mechanical energy, and cools the vaporized working fluid after it has passed through the expander, wherein the fluorinated epoxide compound is substantially free of bonded to carbon Atoms of hydrogen atoms.

Finally, in another aspect, there is provided an apparatus for converting thermal energy to mechanical energy in a Rankine cycle comprising a working fluid; a heat source for vaporizing the working fluid and forming a vaporized working fluid; a turbine for vaporizing the working fluid passing through, thereby converting thermal energy into mechanical energy; a condenser, for cooling the vaporized working fluid after it passes through the turbine; and a pump, for recirculating the working fluid, wherein the working fluid comprises a fluorinated epoxy.

In this disclosure:

"Critical temperature and critical pressure" means the temperature and pressure at which the vapor of the liquid within the sealed system has the same density as the liquid.

"Cchain heteroatom" means an atom other than a carbon atom (eg, oxygen and nitrogen) that is bonded to a carbon atom in a carbon chain to form a carbon-heteroatom-carbon chain;

"device" means an object or design that is heated, cooled or maintained at a predetermined temperature;

"inert" means a chemical composition that is not normally chemically reactive under normal conditions of use;

"Fluorinated" means a hydrocarbon compound having one or more C-H bonds replaced by C-F bonds;

"Epoxide" means a substituted hydrocarbon containing at least one epoxy group, and

"Perfluoro" (for example, as it relates to a group or moiety such as "perfluoroalkylene" or "perfluoroalkylcarbonyl" or "perfluorinated") means perfluorinated such that unless otherwise Indicated, otherwise there are no carbon-bonded hydrogen atoms that could be replaced by fluorine.

Provided methods and apparatus comprising fluorinated epoxies as organic Rankine cycle working fluids can have lower boiling points, higher critical pressures and temperatures, and Good thermal stability. The provided Rankine cycle working fluids can be more efficient in energy transfer and still be used in systems with simple equipment designs.

The above summary is not intended to describe each disclosed embodiment of every implementation of the present invention. The BRIEF DESCRIPTION OF THE DRAWINGS and the following Detailed Description more particularly exemplify exemplary embodiments.

Description of drawings

Figure 1 is a schematic diagram of an apparatus for converting thermal energy into mechanical energy in a Rankine cycle.

Figure 2 is a schematic diagram of a Rankine cycle apparatus including a heat exchanger.

Figure 3 is a graph (temperature entropy diagram) of an embodiment of the provided method.

Detailed ways

In the following description, reference is made to the accompanying drawings which form a part hereof, and in which are shown by way of illustration several specific embodiments. It is to be understood that other embodiments may be conceived and practiced without departing from the scope or spirit of the invention. Therefore, the following specific embodiments are not limiting.

Unless otherwise indicated, all numerical values expressing characteristic dimensions, quantities and physical properties used in the specification and claims are to be understood as being modified in all instances by the term "about". Accordingly, unless indicated to the contrary, the numerical parameters set forth in the foregoing specification and attached claims are approximations that can be determined depending upon the desired properties sought to be obtained by those skilled in the art utilizing the teachings disclosed herein. Variety. The recitation of numerical ranges by endpoints includes all numbers within that range (eg, 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5) and any range within that range.

A method is provided for converting thermal energy to mechanical energy in a Rankine cycle comprising a working fluid comprising a fluorinated epoxide. Referring to FIG. 1 , a typical Rankine cycle system 100 is shown that includes an evaporator/boiler 120 that receives heat from an external source. The evaporator/boiler 120 vaporizes the organic Rankine working fluid contained in the closed system 100 . The Rankine cycle system 100 also includes a turbine 160 that is driven in the system by the vaporized working fluid and used to turn a generator 180 to generate electrical energy. The vaporized working fluid is then directed through condenser 140, which removes excess heat and reliquefies the liquid working fluid. The electric pump 130 increases the pressure of the liquid leaving the condenser 140 and also pumps it back into the evaporator/boiler 120 for further use in the cycle. The heat released by condenser 140 can then be used for other purposes, including driving a secondary Rankine system (not shown).

It is generally desirable to have a fluid with a saturated vapor curve that is isentropic or has a positive gradient. In cases where the saturated vapor curve has a positive gradient, the Rankine can be improved by using an additional heat exchanger (or heat exchangers) to recover heat from the vapor leaving the expander and using the recovered heat to preheat the liquid coming out of the pump. cycle efficiency. Figure 2 is a schematic representation of a Rankine cycle system including a heat exchanger.

Referring to Figure 2, a Terankine cycle system 200 is shown that includes an evaporator/boiler 220 that receives heat from an external source. Evaporator/boiler 220 evaporates the organic Rankine working fluid contained in closed system 200 . The Rankine cycle system 200 also includes a turbine 260 that is driven in the system by the vaporized working fluid and used to turn a generator 270 to generate electrical energy. The vaporized working fluid is then directed through heat exchanger 280 where some excess heat is removed, and from heat exchanger 280 to condenser 250 where the working fluid condenses back into a liquid. The electric pump 240 increases the pressure of the liquid leaving the condenser 250 and also draws it back into the heat exchanger 280 where it is preheated before returning to the evaporator/boiler 220 for further use in the cycle. The heat released by condenser 250 can then be used for other purposes, including driving a secondary Rankine system (not shown).

The provided devices and methods include fluorinated epoxies. Fluorinated epoxies useful in the provided compositions and methods can be epoxies with fully fluorinated (perfluorinated) carbon backbones (i.e., substantially all of the hydrogen atoms in the carbon backbone have been replaced with fluorine) compounds, or epoxides which may have a fully or partially fluorinated carbon backbone with up to three hydrogen atoms in some embodiments, or combinations thereof. The use of fluorinated epoxides in apparatus comprising a device and a mechanism for transferring heat to or from the device is disclosed in applicant's co-pending patent application US Attorney Docket No. 67218US002, filed on the same day as this case.

In addition to providing the thermophysical properties required for use in organic Rankine systems, fluorinated epoxides also exhibit desirable environmental benefits. It has also been found that many compounds which exhibit high stability in use are very stable in the environment. Perfluorocarbons and perfluoropolyethers have been shown to have high stability, but have also been shown to have long atmospheric lifetimes, which lead to high global warming potential. Atmospheric lifetimes of C ₆ F ₁₄ and CF ₃ OCF(CF ₃ ) CF ₂ OCF ₂ OCF ₃ have been reported to be 3200 and 800 years, respectively (see Climate Change 2007: Physical Science Basis, Working Group I dedicated to Intergovernmental Climate Change Contributions to the Committee's Fourth Assessment Report, Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, KB Veryt, M. Tignor and HLMiller (eds.), Cambridge University Press (Cambridge, UK and New York, NY, USA), p. 996, 2007). Fluorinated epoxides have been found to degrade in the environment on a time scale, which leads to a significantly shortened atmospheric lifetime and lower global warming potential compared to perfluorocarbons and perfluoropolyethers. According to kinetic studies of the reaction with hydroxyl groups, 2,3-difluoro-2-(1,2,2,2-tetrafluoro-1-trifluoromethyl-ethyl)-3-trifluoromethyl-cyclo Oxides have an estimated atmospheric lifetime of 20 years. In a similar kinetic study, 2-fluoro-2-pentafluoroethyl-3,3-bis-trifluoromethyl-epoxide showed an estimated atmospheric lifetime of 77 years. As a result of their shorter atmospheric lifetimes, fluorinated epoxides have lower global warming potential and are expected to contribute significantly less to global warming than perfluorocarbons and perfluoropolyethers.

The provided fluorinated epoxides can be derived from fluorinated olefins that have been oxidized using epoxidation reagents. In the provided fluorinated epoxy compositions, the carbon backbone includes the entire carbon backbone including the longest hydrocarbon chain (backbone) and any branched carbon chains of the backbone. In addition, there may be one or more catenary heteroatoms interrupting the carbon backbone, such as oxygen and nitrogen, eg ether or trivalent amine functional groups. Chain heteroatoms are generally not bonded directly to the epoxy ring. In these cases, the carbon backbone includes heteroatoms and a carbon skeleton attached to the heteroatoms.

Typically, the vast majority of the halogen atoms attached to the carbon backbone are fluorine; most typically, substantially all of the halogen atoms are fluorine, so that the epoxide is a perfluorinated epoxide. The provided fluorinated epoxides can have a total of 4 to 12 carbon atoms. Representative examples of fluorinated epoxide compounds suitable for use in the provided methods and compositions include 2,3-difluoro-2,3-bis-trifluoromethyl-epoxide, 2,2,3-trifluoro -3-Pentafluoroethyl-epoxide, 2,3-difluoro-2-(1,2,2,2-tetrafluoro-1-trifluoromethyl-ethyl)-3-trifluoromethyl -epoxide, 2-fluoro-2-pentafluoroethyl-3,3-bis-trifluoromethyl-epoxide, 1,2,2,3,3,4,4,5,5, 6-Decafluoro-7-oxa-bicyclo[4.1.0]heptane, 2,3-difluoro-2-trifluoromethyl-3-pentafluoroethyl-epoxide, 2,3-di Fluoro-2-nonafluorobutyl-3-trifluoromethyl-epoxide, 2,3-difluoro-2-heptafluoropropyl-3-pentafluoroethyl-epoxide, 2-fluoro- 3-Pentafluoroethyl-2,3-bis-trifluoromethyl-epoxide, 2,3-bis-pentafluoroethyl-2,3-bistrifluoromethyl-epoxide, 2,3 -bis-trifluoromethyl-epoxide, 2-pentafluoroethyl-3-trifluoromethyl-epoxide, 2-(1,2,2,2-tetrafluoro-1-trifluoromethyl -ethyl)-3-trifluoromethyl-epoxide, 2-nonafluorobutyl-3-pentafluoroethyl-epoxide, 2-fluoro-2-trifluoromethyl-epoxide, 2,2-Bis-trifluoromethyl-epoxide, 2-fluoro-3-trifluoromethyl-epoxide, 2-heptafluoroisopropylepoxide, 2-heptafluoropropylepoxide compounds,

2-nonafluorobutyl epoxide, 2-tridecafluorohexyl epoxide, and epoxides of HFP trimers, including 2-pentafluoroethyl-2-(1,2,2,2-tetrafluoro- 1-trifluoromethyl-ethyl)-3,3-bis-trifluoromethyl-epoxide, 2-fluoro-3,3-bis-(1,2,2,2-tetrafluoro-1 -Trifluoromethyl-ethyl)-2-trifluoromethyl-epoxide, 2-fluoro-3-heptafluoropropyl-2-(1,2,2,2-tetrafluoro-1-tri Fluoromethyl-ethyl)-3-trifluoromethyl-epoxide, 2-(1,2,2,3,3,3-hexafluoro-1-trifluoromethyl-propyl)-2, 3,3-tri-trifluoromethyl-epoxide and 2-[1,1,2,3,3,3-hexafluoro-2-(trifluoromethyl)propyl]-2-(trifluoromethyl) methyl) epoxide.

The provided fluorinated epoxide compounds can be passed through the corresponding fluorine using oxidizing agents (such as sodium hypochlorite, hydrogen peroxide) or other well-known epoxidation reagents (such as peroxycarboxylic acids, such as m-chloroperoxybenzoic acid or peracetic acid). Produced by epoxidation of alkenes. Fluorinated olefin precursors are directly available: as, for example, in 1,1,1,2,3,4,4,4-octafluoro-but-2-ene (for the preparation of 2,3-difluoro-2, 3-bis-trifluoromethyl epoxide), 1,1,1,2,3,4,4,5,5,5-decafluoro-pent-2-ene or 1,2,3,3, 4,4,5,5,6,6 decafluoro-cyclohexene (for the preparation of 1,2,2,3,3,4,4,5,5,6-decafluoro-7-oxa-bicyclic [4.1.0] in the case of heptane). Other useful fluorinated olefin precursors may include oligomers, such as dimers and trimers, of hexafluoropropylene (HFP) and tetrafluoroethylene (TFE). HFP oligomers can be prepared by reacting 1,1,2,3,3,3-hexafluoro-1-propene (hexafluoropropylene) with selected Contact with catalysts or catalyst mixtures of alkali metal, quaternary ammonium and phosphonium cyanides, cyanates and thiocyanates. The preparation of these HFP oligomers is disclosed, for example, in US Patent No. 5,254,774 (Prokop). Useful oligomers include HFP trimers or HFP dimers. HFP dimers include a mixture of the cis and trans isomers of perfluoro-4-methyl-2-pentene shown in Table 1 in the Examples section below. HFP trimers include a mixture of isomers of C ₉ F ₁₈ . This mixture has the six main components also listed in Table 1 in the Examples section.

The provided fluorinated epoxide compounds can have a boiling point in the range of about -10°C to about 150°C. In some embodiments, the fluorinated epoxide compound can have a boiling point in the range of about 0°C to about 55°C. Certain exemplary materials and their boiling point ranges are disclosed in the Examples section below.

Provided methods for converting thermal energy to mechanical energy in a Rankine cycle include vaporizing a working fluid comprising a fluorinated epoxide using a heat source to form a vaporized working fluid. In some embodiments, heat is transferred from a heat source to a working fluid in an evaporator or boiler. The vaporized working fluid is under pressure and is available to do work by expansion. The heat source can be in any form, for example from fossil fuels such as oil, coal or natural gas. Additionally, in some embodiments, the heat source may be from nuclear power, solar power, or fuel cells. In other embodiments, the heat may be "waste heat" from other heat transfer systems that would otherwise be lost to the atmosphere. In some embodiments, "waste heat" may be heat recovered from the second Rankine cycle system in the condenser and other cooling devices in the second Rankine cycle.

An additional source of "waste heat" can be found in landfills where methane gas flares off. To prevent methane gas from entering the environment and thus contributing to global warming, methane gas from landfills can be burned by "flash burning" to produce carbon dioxide and water, both of which are less environmentally harmful than methane in terms of global warming potential. Other sources of "waste heat" that can be used in the provided methods are geothermal sources and heat from other types of engines such as gas turbines that release large amounts of heat in their exhaust gases and cool liquids such as water and lubricants.

In the provided method, the vaporized working fluid is expanded by a device that can convert the pressurized working fluid into mechanical energy. In some embodiments, the vaporized working fluid is expanded by a turbine that can rotate a shaft by the pressure of the vaporized working fluid expanding. The turbine can then be used to do mechanical work, such as in some embodiments, to operate a generator, thereby producing electricity. In other embodiments, a turbine may be used to drive a belt, wheel, gear, or other device that may transfer mechanical work or energy for use in an attachment or connection device.

After the vaporized working fluid has been converted to mechanical energy, the vaporized (and now expanded) working fluid can be condensed using a cooling source to liquefy for reuse. The heat released by the condenser can be used for other purposes, including being recycled to the same or another Rankine cycle system, thereby saving energy. Finally, the condensed working fluid can be pumped back into the boiler or evaporator for reuse in a closed system.

Desirable thermodynamic properties of organic Rankine cycle working fluids are well known to those of ordinary skill and are discussed, for example, in US Patent Application Publication No. 2010/0139274 (Zyhowski et al.). After condensation, the greater the difference between the temperature of the heat source and the temperature of the condensing liquid or provided heat sink, the more thermodynamically efficient the Rankine cycle. Affects thermodynamic efficiency by matching the working fluid to the heat source temperature. The closer the evaporation temperature of the working fluid is to the source temperature, the more efficient the system will be. Toluene can be used, for example, in the temperature range of 79°C (the boiling point of toluene) to about 260°C, but toluene has toxicological and flammability problems. Fluids such as 1,1-dichloro-2,2,2-trifluoroethane and 1,1,1,3,3-pentafluoropropane may alternatively be used in this temperature range. But 1,1-dichloro-2,2,2-trifluoroethane can form toxic compounds below 300°C and needs to be limited to an evaporation temperature of about 93°C to about 121°C. Therefore, there is a need for other environmentally friendly Rankine cycle working fluids with higher critical temperatures so that source temperatures such as gas turbine and internal combustion engine exhaust can be better matched to the working fluid. In addition, fluids with higher heat capacity promote higher Rankine cycle efficiencies due to improved thermal energy utilization—recovering greater energy from self-expansion.

Also provided is an apparatus for converting thermal energy to mechanical energy in a Rankine cycle comprising: a working fluid comprising a fluorinated epoxide; a heat source for vaporizing the working fluid and forming the vaporized working fluid; a turbine , to convert the thermal energy (and pressure) of the vaporized working fluid into mechanical energy; the condenser, to cool the vaporized working fluid after it has transferred the energy to the turbine; and the pump, to recirculate the working fluid and build up the pressure. In the provided methods and as described above, the recirculated working fluid can then be reheated in the evaporator boiler.

Objects and advantages of this invention are further illustrated by the following examples, but the particular materials and amounts thereof recited in these examples, as well as other conditions and details, should not be construed to unduly limit this invention. The device is usually closed loop.

example

Table 1

Material

Material

Example 1-2,3-difluoro-2-(1,2,2,2-tetrafluoro-1-trifluoromethyl-ethyl)-3-trifluoromethyl-ring Synthesis of oxides. (C ₆ f ₁₂ O)

In a 1.5 L glass reactor equipped with a mixer and cooling jacket, add 400 g of acetonitrile, 200 g of 1,1,1,2,3,4,5,5,5-nonafluoro-4-trifluoromethyl- pent-2-ene and 150 grams of 50% potassium hydroxide. The reactor temperature was controlled at 0°C using a reactor cooling jacket. Then 100 grams of 50% hydrogen peroxide was slowly added to the reactor under vigorous mixing while controlling the reactor temperature at 0°C. After all the hydrogen peroxide had been added in about 2 hours, the mixer was turned off to allow the crude product to separate from the solvent and aqueous phase. 155 g of crude product were collected from the bottom product phase. The crude product was then washed with 200 g of water to remove the solvent acetonitrile and then purified in a 40-plate Oldershaw fractionation column with condenser cooling to 15°C. The fractionation column was operated such that the reflux ratio (distillate flow back to the fractionation column compared to distillate flow to the product collection cylinder) was 10:1. When the head temperature in the fractionation column was between 52°C and 53°C, the final product was collected as condensate.

90 g of the final product collected from the above method was analyzed by 376.3 MHz ¹⁹ F-NMR spectrum and identified as 95.8% 2,3-difluoro-2-(1,2,2,2-tetrafluoro-1-tri Mixture of fluoro-methyl-ethyl)-3-trifluoromethyl-epoxide and 2.2% of 2-fluoro-2-pentafluoroethyl-3,3-bis-trifluoromethyl-epoxide .

Example 2-1,2,2,3,3,4,4,5,5,6-decafluoro-7-oxa-bicyclo[4.1.0]heptane epoxide Synthesis and purification. c(C ₆ f ₁₂ O)

In a 1.5 liter glass reactor equipped with a mixer and a cooling jacket, 400 g of acetonitrile, 200 g of 1,2,3,3,4,4,5,5,6,6-decafluoro-cyclohexene (89.3 % purity) and 150 grams of 50% potassium hydroxide. The reactor temperature was controlled at 0°C using a reactor cooling jacket. Then 100 grams of 50% hydrogen peroxide was slowly added to the reactor under vigorous mixing while controlling the reactor temperature at 0°C. After all the hydrogen peroxide had been added in about 2 hours, the mixer was turned off to allow the crude product to separate from the solvent and aqueous phase. 100 g of crude product were collected from the bottom product phase. The crude product was then washed with 100 g of water to remove the solvent acetonitrile and then purified in a 40-plate Oldershaw fractionation column with condenser cooling to 15°C. The fractionation column was operated such that the reflux ratio (distillate flow back to the fractionation column compared to distillate flow to the product collection cylinder) was 10:1. When the head temperature in the fractionation column is between 47°C and 55°C, the final product is collected as condensate.

70 g of the final product collected from the above method was analyzed by ¹⁹ F-NMR spectroscopy at 376.3 MHz and identified as 1,2,2,3,3,4,4 with a purity of 94.1% with an additional 2.6% of isomers , 5,5,6-Decafluoro-7-oxa-bicyclo[4.1.0]heptane.

Example 3 - Synthesis and purification of C9 epoxide of HFP trimer-epoxide (C ₉ F ₁₈ O ) .

Into a 1.5 liter glass reactor equipped with a mixer and cooling jacket were added 400 grams of acetonitrile, 200 grams of HFP trimer (C ₉ F ₁₈ ) and 150 grams of 50% potassium hydroxide. The reactor temperature was controlled at 0°C using a reactor cooling jacket. Then, 100 grams of 50% hydrogen peroxide was slowly added to the reactor under vigorous stirring while controlling the temperature of the reactor between 0°C and 20°C. After all the hydrogen peroxide had been added in about 2 hours, the mixer was turned off to allow the crude product to separate from the solvent and aqueous phase. 180 g of crude product were collected from the bottom product phase. The crude product was then washed with 200 g of water to remove the solvent acetonitrile and then purified in a 40-plate Oldershaw fractionation column with condenser cooling to 15°C. The fractionation column was operated such that the reflux ratio (distillate flow back to the fractionation column compared to distillate flow to the product collection cylinder) was 10:1. When the head temperature in the fractionation column is between 120°C and 122°C, the final product is collected as condensate.

150 g of the final product collected by the above method was analyzed by 376.3 MHz ¹⁹ F-NMR spectrum and identified as an epoxide (C ₉ F ₁₈ O) of HFP trimer with 5 isomeric forms. The sum of the 5 isomers has a purity of 99.4%.

Table II shows some thermophysical properties of an exemplary fluorinated epoxide and a comparative material (dodecafluoro-2-methylpentan-3-one).

Example 4 - Synthesis of 2-nonafluorobutyl epoxide (C ₄ F ₉ CH(O)CH ₂ ) .

Epoxides were prepared according to a modification of the method of WO2009/096265 (Daikin Industries Ltd.). A 500 mL magnetically stirred three-neck round bottom flask was equipped with a water condenser, thermocouple and addition funnel. The flask was cooled in a water bath. Into the flask was placed C ₄ F ₉ CH=CH ₂ (50 g, 0.2 moles, Alfa Aesar), N-bromosuccinimide (40 g, 0.22 moles, Aldrich Chemical Company) and dichloromethane as solvent (250 mL). Chlorosulfonic acid (50 g, 0.43 moles, Alfa Aesar) was placed in an addition funnel and slowly added to the stirred reaction mixture while maintaining the reaction temperature below 30°C. After the addition was complete, the reaction mixture was maintained at ambient temperature for 16 hours. The entire reaction mixture was then carefully poured onto ice, the lower dichloromethane phase was separated and washed once with the same volume of water, and the solvent was removed by rotary evaporation, yielding 82 g of The chlorosulfite C ₄ F ₉ CHBrCH ₂ OSO ₂ Cl, and it contains some C ₄ F ₉ CHBrCH ₂ Br. The chlorosulfite mixture was used without further purification in the next step.

Chlorosulfite, benzyltrimethylammonium chloride (0.6 g, 0.003 mol, Alfa Aesar), and water (350 mL) were placed in a 1 L magnetically stirred vessel equipped with a water condenser, thermocouple, and addition funnel. Three neck round bottom flask. A solution of potassium iodide (66.3 g, 0.4 mole, EMD Chemicals) dissolved in water (66 mL) was placed in a separatory funnel and the chlorosulfite solution was added dropwise over about 1.5 hours and the mixture was stirred at ambient temperature for 16 hours. Dichloromethane (300 mL) was then added, the mixture was filtered and the filter cake was washed with an additional 100 mL of dichloromethane. The dichloromethane layer was separated and the remaining aqueous layer was extracted with an additional 200 mL of dichloromethane. The dichloromethane solvent was then removed by rotary evaporation. The residue combined with material from another preparation was distilled bp = 66-70°C/20 torr and the distillate redissolved in dichloromethane and washed once with 5% aqueous sodium bisulfite to remove iodine and pass through Solvent was removed by rotary evaporation. At this stage, the desired product bromohydrin (82 g) C ₄ F ₉ CHBrCH ₂ OH was 87% pure and contained about 5% C ₄ F ₉ CHBrCH ₂ Br and 8% C ₄ F ₉ CHClCH ₂ Br.

Bromohydrin (82 g), diethyl ether solvent (200 mL) and tetrabutylammonium bromide (3.0 g, 0.009 mole, Aldrich) were placed in a 500 mL magnetically stirred round bottom flask equipped with a condenser and thermocouple. To this mixture was added a solution of sodium hydroxide (24 g, 0.6 mole) in water (33 g) in one portion. The mixture was stirred vigorously for four hours. The ether solution was then washed once with saturated sodium chloride solution and once with 5% HCl solution, and then dried over magnesium sulfate and the residue was fractionated by concentric columns, and fractions boiling at 101°C were collected to afford the product (40.9 g) which was 88.5% of the desired _{epoxide C4F9CH} (O) _CH2 and 7.3% of the _{bromoalkene C4F9CBr} = _CH2 . Pass an epoxide/bromoolefin mixture (which was degassed three times under nitrogen using a Firestone valve connected to a dry nitrogen source and a mineral oil bubbler) with 2,2'-azobis(2-methylpropionitrile) [0.5 g, 0.003 mol, Aldrich] and bromine [4.0 g, 0.025 mol, Aldrich] were reacted at 65 °C for eight hours for final purification by removal of the epoxy groups of most bromoalkenes. The reaction mixture was treated with 5% by weight sodium bisulfite in water to remove excess bromine, the phases were separated and the lower phase was rectified by concentric column to provide the final epoxide (25 g ). Product identity was confirmed by GCMS, H-1 and F-19 NMR spectrometers.

Example 5 - Synthesis of 2-tridecafluorohexyl epoxide (C ₆ F ₁₃ CH(O)CH ₂ ) .

A 1 L magnetically stirred three-neck round bottom flask was equipped with a water condenser, thermocouple and addition funnel. The flask was cooled in a water bath. Into the flask was placed fuming sulfuric acid (20% _SO3 content) (345 g, 0.86 moles _SO3 , Aldrich) and bromine (34.6 g, 0.216 moles, Aldrich). Into the addition funnel was placed _C6F13CH = _CH2 (150 g, 0.433 mol, Alfa Aesar) which was added to _the acid solution over a period of two hours. No obvious exotherm. The reaction mixture was stirred at ambient temperature for 16 hours. Water (125 g) was placed in the separatory funnel and added very carefully over a period of about two hours. The initial 5-10 g addition was extremely exothermic. Once the addition was complete, more water (50 g) was added in one portion and the reaction mixture was heated to 90°C for 16 hours. Diethyl ether (300 mL) was added to the reaction mixture and the two phases separated, the lower phase containing the product. The remaining aqueous phase (150 mL) was re-extracted with ether and the upper ether phase was separated and combined with the previous lower phase. The ether layer was washed with 5 wt% aqueous potassium hydroxide _solution , and the solvent was removed _by rotary evaporation to afford 112 g of a white crystalline solid, _which was about 72% _{C6F13CHBrCH2OH} , 8% _{C6F13 CHBrCH2Br} and 19% ( _{C6F13CHBrCH2O ) SO2 .} The solid was distilled and the fraction boiling range = 68-74°C/6 Torr collected (36 g) was found to be 90.7% of the desired bromohydrin and 9.3% of the dibromide.

The bromohydrin mixture was then placed into a 250 mL magnetically stirred round bottom flask equipped with a water condenser and thermocouple, along with tetrabutylammonium bromide (1.5 g, 0.005 mol, Aldrich) dissolved in 5 g of water and A solution of 8.2 g of sodium hydroxide (0.2 mole) dissolved in 15 g of water. After one hour of vigorous stirring, the reaction mixture was analyzed by gas-liquid chromatography, which showed about 40% conversion of bromohydrin to epoxide. The reaction was stirred for an additional 5 hours. The lower aqueous phase was separated and the remaining ether phase was washed once with dilute aqueous hydrochloric acid prepared by adding a few drops of 2N aqueous HCl to 50 mL of water, dried over magnesium sulfate and distilled to afford the product in 98.3% purity (bp = 144°C) Epoxide (12 g _{) C6F13CH} (O) _CH2 and 1.5% bromoalkene _C6F13CBr = _{CH2 .} The product structure was confirmed by GCMS, H-1 and F-19 NMR.

Example 6-2-[1,1,2,3,3,3-hexafluoro-2-(trifluoromethyl)propyl]-2-(trifluoromethyl)epoxidation The preparation of the material ((CF ₃ ) ₂ CFCF ₂ C(CF ₃ )OCH ₂ )

In a 600 mL Parr reactor, charge hexafluoropropylene dimer (300 g, 1.0 mol 3M), methanol (100 g, 3.12 mol, Aldrich) and TAPEH (2-ethylperoxyhexanoic acid tert-amyl ester) (4 g, 0.017 mol). The reactor was sealed and the temperature was set to 75 °C. After stirring at this temperature for 16 hours, the reactor contents were emptied and washed with water to remove excess methanol. The recovered fluorochemical phase was dried over anhydrous magnesium sulfate and filtered. The reaction was repeated two more times to yield a total of 500 g of product (2,3,4,5,5,5-hexafluoro-2,4-bis(trifluoromethyl)pentan-1-ol). The crude reaction product was then purified by fractional distillation using a 15-plate Oldershaw column. The fluorinated alcohol product 2,3,4,5,5,5-hexafluoro-2,4-bis(trifluoromethyl)pentan-1-ol (257 g, 0.77 mol) was charged with magnetic stirring, cold water condensation 1 L round bottom flask with a thermocouple (J-Kem controller) and dropping funnel. Thionyl chloride (202.25 g, 1.7 mol, Aldrich) was added to the fluorinated alcohol at room temperature via a dropping funnel. Once the addition was complete, the temperature was increased to 85°C until no further outgassing was observed. The water condenser was removed and the 1-plate distillation apparatus was put in place. Excess thionyl chloride was then distilled from the reaction mixture. 300 g of product was collected. This product was charged to a flask containing 150 g of potassium fluoride in 500 mL of N-methyl-pyrrolidone solvent. The reaction mixture was then stirred overnight at 35°C. The next day the reaction flask was set up for distillation and the product 3,3,4,5,5,5-hexafluoro-2,4-bis(trifluoromethyl)pent-1-ene was distilled from the reaction flask. Collect a total of 140g.

In a 500mL jacketed reaction flask equipped with overhead stirring, cold water condenser, N bubbler and thermocouple, sodium hydroxide (2.5g, 0.0636mol, Aldrich Company), sodium hypochlorite (12% concentration, 80g, 0.127mol), Aliquat336 (1g, Alfa Aisha Company). The flask was cooled to 4°C. The olefin 3,3,4,5,5,5-hexafluoro-2,4-bis(trifluoromethyl)pent-1-ene (20 g, 0.0636 mol) was charged to the mixture, which was then stirred for 2 hours . After 2 hours, stirring was stopped and the lower FC phase was separated from the mixture. A total of 20g FC was collected. A sample thereof was analyzed by ¹⁹ F, ¹ H and ¹³ C NMR, and it was determined that 2-[1,1,2,3,3,3-hexafluoro-2-(trifluoromethyl)propyl]-2-( Product structures of trifluoromethyl)epoxides.

Table II

Thermophysical Properties of Fluorinated Epoxy and Comparative Materials

Table II was determined from the molecular structure using the Wilson-Jasperson method given in Reid, Prausnitz and Poling, The Properties of Gases and Liquids, Fifth Edition, McGraw-Hill, 2000 Critical temperature and pressure of fluorinated epoxides in . The critical density was calculated using Joback's method given in Reid, Prausnitz and Poling, "The Properties of Gases and Liquids", Fifth Edition, McGraw-Hill, 2000. Volume displacement imposed by liquid density, using Peng-Robinsion's equation of state (Peng, D.Y., and Robinson, D.B., Ind. & Eng. Chem. Fund. 15: 59-64 , 1976) to derive the thermodynamic properties of exemplary fluorinated epoxides. The required inputs for the state equation are critical temperature, critical density, critical pressure, eccentricity factor, molecular weight, and ideal gas heat capacity. The ideal gas heat capacity was calculated using the group contribution method (Rihani, D. and Doraiswamy, L. Ind. & Eng. Chem. Fund., 4, p. 17, 1965). For Comparative Example 1, in the functional form described by Lemmon E.W., Mclinden M.O. and Wagner W. in "Chemical and Engineering Data" (J.Chem. & Eng.Data) 54: 3141-3180 pages, 2009, the The thermophysical property data were fitted with the Helmholtz equation of state.

Figure 3 shows the temperature entropy diagrams of Examples 1, 2 and 3 (Ex.1, Ex.2 and Ex.3) and Comparative Example 1 (Comp.1). Each curve was generated using the state equations described above for each fluid. While all fluids have saturated vapor lines with positive gradients, Examples 1, 2, and 3 have larger proportional drops, requiring less desuperheating (or heat exchange) after expansion, which is similar to the Rankine cycle of Figure 2 Constructed heat exchangers may be advantageous when sizing heat exchangers.

A Rankine cycle according to the configuration of Figure 1 and operated between 50°C and 140°C was used to evaluate the performance of exemplary fluorinated epoxides and comparative examples. The Rankine cycle was modeled using thermodynamic properties calculated from state equations and methods described in Cengel Y.A. and Boles M.A., Thermodynamics: An Engineering Approach, 5th ed.; McGrawHill, 2006. The cycle has a heat input of 1000 kW with working fluid pump and expander efficiencies of 60% and 80%, respectively. The results are shown in Table III. The thermal efficiency of the exemplary fluorinated epoxies is greater than that of the comparative examples.

Table III

Calculated Rankine cycle performance

As noted above, for a given heat source, thermodynamic efficiency in a Rankine cycle can be improved when the boiling point of the working fluid is close to the temperature of the heat source. Therefore, a higher critical temperature results in a greater thermodynamic efficiency. Exemplary fluorinated epoxies can have critical temperatures greater than 175°C, greater than 200°C, or even greater than 230°C, as shown in Table II.

The following are illustrative examples of fluorinated epoxies as organic Rankine cycle working fluids and methods of using them in accordance with aspects of the invention

Embodiment 1 is a method for converting thermal energy into mechanical energy in a Rankine cycle, comprising: vaporizing a working fluid with a heat source to form a vaporized working fluid; expanding the vaporized working fluid through a turbine; cooling with a cooling source the vaporized working fluid to form a condensed working fluid; and pumping the condensed working fluid; wherein the working fluid comprises a fluorinated epoxy.

Embodiment 2 is the method for converting thermal energy to mechanical energy in a Rankine cycle of embodiment 1, wherein the fluorinated epoxide compound includes up to three hydrogen atoms.

Embodiment 3 is the method for converting thermal energy to mechanical energy in a Rankine cycle of embodiment 1, wherein the fluorinated epoxide compound is substantially free of hydrogen atoms bonded to carbon atoms.

Embodiment 4 is the method for converting thermal energy to mechanical energy in a Rankine cycle of embodiment 1, wherein the fluorinated epoxide has a total of about 4 to about 9 carbon atoms.

Embodiment 5 is the method for converting thermal energy to mechanical energy in a Rankine cycle according to embodiment 4, wherein the fluorinated epoxide contains 6 carbon atoms.

Embodiment 6 is the method for converting thermal energy to mechanical energy in a Rankine cycle of embodiment 1, wherein the fluorinated epoxide has a critical temperature greater than about 150°C.

Embodiment 7 is the method for converting thermal energy to mechanical energy in a Rankine cycle of embodiment 1, wherein the turbine generates electrical energy.

Embodiment 8 is the method for converting thermal energy to mechanical energy in a Rankine cycle of embodiment 1, wherein the vaporized working fluid is at a pressure greater than ambient pressure.

Embodiment 9 is a method of recovering waste heat comprising: passing a liquid working fluid through a heat exchanger in communication with a process that generates waste heat to produce a vaporized working fluid; removing said vaporized working fluid from said heat exchanger fluid; passing the vaporized working fluid through an expander, wherein the waste heat is converted to mechanical energy; and cooling the vaporized working fluid after it has passed through the expander, wherein the fluorinated epoxide compound is substantially contains no hydrogen atoms bonded to carbon atoms.

Embodiment 10 is the method for recovering waste heat of embodiment 9, wherein the fluorinated epoxide has a total of about 4 to about 9 carbon atoms.

Embodiment 11 is the method for recovering waste heat of embodiment 10, wherein the fluorinated epoxide contains 6 carbon atoms.

Embodiment 12 is the method for recovering waste heat of embodiment 10, wherein the fluorinated epoxide has a critical temperature greater than about 150°C.

Embodiment 13 is an apparatus for converting thermal energy into mechanical energy in a Rankine cycle, comprising: a working fluid; a heat source for vaporizing the working fluid and forming a vaporized working fluid; a turbine for the vaporized a working fluid passing therethrough, thereby converting thermal energy into mechanical energy; a condenser for cooling the vaporized working fluid after it passes through the turbine; and a pump for recirculating the working fluid, wherein the working Fluid contains fluorinated epoxy.

Embodiment 14 is the apparatus for converting thermal energy to mechanical energy in a Rankine cycle of embodiment 13, wherein the working fluid is in a closed loop.

Embodiment 15 is the apparatus for converting thermal energy to mechanical energy in a Rankine cycle according to embodiment 13, wherein the fluorinated epoxide is substantially free of hydrogen atoms bonded to carbon atoms.

Embodiment 16 is the apparatus for converting thermal energy to mechanical energy in a Rankine cycle of embodiment 15, wherein the fluorinated epoxide has a total of about 4 to about 9 carbon atoms.

Embodiment 17 is the apparatus for converting thermal energy to mechanical energy in a Rankine cycle according to embodiment 16, wherein the fluorinated epoxide contains 6 carbon atoms.

Embodiment 18 is the apparatus for converting thermal energy to mechanical energy in a Rankine cycle of embodiment 13, wherein the fluorinated epoxide has a critical temperature greater than about 150°C.

Various modifications and alterations to this invention will become apparent to those skilled in the art without departing from the scope and spirit of this invention. It should be understood that the invention is not intended to be unduly limited by the illustrative embodiments and examples described herein, and that the above embodiments and examples are presented by way of example only, and that the scope of the invention is intended only to be limited by the scope of the invention as set forth herein below. Claims limited. All references cited in this disclosure are hereby incorporated by reference in their entirety.

Claims (18)

1. for the method that is mechanical energy in Rankine cycle by thermal power transfer, it comprises:

Working fluid with thermal source vaporization working fluid with formation vaporization;

By the working fluid of vaporizing described in turbine expansion;

Use the working fluid of the cooling described vaporization of cooling source to form condensation working fluid; With

Aspirate the working fluid of described condensation;

Wherein said working fluid comprises fluorinated epoxide.

2. according to claim 1 for the method that is mechanical energy in Rankine cycle by thermal power transfer, wherein said fluorinated epoxide compound comprises three hydrogen atoms at the most.

3. according to claim 1 for the method that is mechanical energy in Rankine cycle by thermal power transfer, wherein said fluorinated epoxide compound is substantially devoid of the hydrogen atom that is bonded to carbon atom.

4. according to claim 1 for the method that is mechanical energy in Rankine cycle by thermal power transfer, wherein said fluorinated epoxide has approximately 4 to approximately 9 carbon atoms of total.

5. according to claim 4 for the method that is mechanical energy in Rankine cycle by thermal power transfer, wherein said fluorinated epoxide contains 6 carbon atoms.

6. according to claim 1 for the method that is mechanical energy in Rankine cycle by thermal power transfer, wherein said fluorinated epoxide has the critical temperature that is greater than approximately 150 ℃.

7. according to claim 1 for the method that is mechanical energy in Rankine cycle by thermal power transfer, wherein said turbine produces electric energy.

8. according to claim 1 for the method that is mechanical energy in Rankine cycle by thermal power transfer, the working fluid of wherein said vaporization is in being greater than under the pressure of environmental stress.

9. for reclaiming a method for used heat, it comprises:

Make liquid working fluid by the heat exchanger being communicated with to produce the processing of the working fluid of vaporization with generation used heat;

From described heat exchanger, remove the working fluid of described vaporization;

Make the working fluid of described vaporization by expander, wherein said used heat is converted to mechanical energy; With

After the working fluid of described vaporization has passed through described expander, it is cooling, wherein said fluorinated epoxide compound is substantially devoid of the hydrogen atom that is bonded to carbon atom.

10. according to claim 9 for reclaiming the method for used heat, wherein said fluorinated epoxide has approximately 4 to approximately 9 carbon atoms of total.

11. is according to claim 10 for reclaiming the method for used heat, and wherein said fluorinated epoxide contains 6 carbon atoms.

12. is according to claim 10 for reclaiming the method for used heat, and wherein said fluorinated epoxide has the critical temperature that is greater than approximately 150 ℃.

13. 1 kinds for the equipment that is mechanical energy in Rankine cycle by thermal power transfer, and it comprises:

Working fluid;

Thermal source, for vaporizing described working fluid and forming the working fluid of vaporizing;

Turbine, the working fluid of described vaporization passes through through it, thereby is mechanical energy by thermal power transfer;

Condenser, for the working fluid in described vaporization by it is cooling after described turbine; With

Pump, for working fluid described in recirculation,

Wherein said working fluid comprises fluorinated epoxide.

14. is according to claim 13 for the equipment that is mechanical energy in Rankine cycle by thermal power transfer, and wherein said working fluid is in closed loop.

15. is according to claim 13 for the equipment that is mechanical energy in Rankine cycle by thermal power transfer, and wherein said fluorinated epoxide is substantially devoid of the hydrogen atom that is bonded to carbon atom.

16. is according to claim 15 for the equipment that is mechanical energy in Rankine cycle by thermal power transfer, and wherein said fluorinated epoxide has approximately 4 to approximately 9 carbon atoms of total.

17. is according to claim 16 for the equipment that is mechanical energy in Rankine cycle by thermal power transfer, and wherein said fluorinated epoxide contains 6 carbon atoms.

18. equipment that are mechanical energy by thermal power transfer in Rankine cycle according to claim 13, wherein said fluorinated epoxide has the critical temperature that is greater than approximately 150 ℃.

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