Continuous reaction method by solid/gas catalysis in unconventional medium, corresponding reactor and use of said reactor

Abstract

The invention concerns a continuous reaction method by solid/gas catalysis in unconventional medium, using different substrates to obtain predetermined products, substrates and products forming compounds, which consists in controlling: the reaction in temperature to determine the saturation pressure of each pure compound taking part in determining the compound thermodynamic activity; the total pressure at a level lower than atmospheric pressure; the molar flow rates of the compounds and the vector gas, to adjust the gas mixture molar composition on the basis of the predetermined values of the thermodynamic activity of said compounds.

1 . Continuous reaction process by solid/gas catalysis in unconventional medium, making use of different substrates to obtain defined products, substrates and products forming compounds, consisting of controlling: 
 the reaction temperature to determine the saturation pressure of each pure compound implicated in the determination of the thermodynamic activity of said compound;    the total pressure;    the molar fluxes of the compounds and the vector gas, in order to control the molar composition of the gas mixture as a function of the thermodynamic activity values determined for these compounds.    
     
     
         2 . Process according to  claim 1 , characterized in that in order to avoid constant modification of the composition of the gas phase over the course of time, the gas to be converted during the reaction results from a liquid-vapour flash applied to a liquid mixture, followed by the optional addition of a neutral gas.  
     
     
         3 . Process according to either of the claims  1  or  2 , characterized in that the vector gas is replaced by the compound with substantially the lowest boiling point and by selecting the thermodynamic activity value of water by application of an appropriate temperature and pressure couple.  
     
     
         4 . Reactor according to one of the  claim 2  and  3 , characterized in that in the case where a neutral vector gas is used this gas is recycled by recompression at its vacuum pump outlet and by transference to a heat exchanger.  
     
     
         5 . Reactor according to  claim 4 , characterized in that the vacuum pump is coupled to a compressor.  
     
     
         6 . Reactor for implementing the process according to  claim 1 , comprising controllers ( 6 ,  8 ) of the fluxes of each of the substrates ( 1 ) and of the vector gas ( 7 ), probes for temperature control ( 15  to  18 ) of an expansion mixer ( 4 ) of the substrates in the gas phase, of a reaction chamber ( 10 ) comprising a bioreactor ( 8 ) containing a catalyst and in which the substrates are introduced via a heat exchanger ( 9 ), of the bioreactor ( 8 ) and of an analytical sampler ( 14 ) situated at the outlet of the reaction chamber, a vacuum pump ( 11 ) coupled to a vacuum regulation valve ( 12 ) also mounted at the outlet of the reaction chamber, the pumps, probes and the valve being connected to a command controller ( 20 ) coupled to a management processor ( 21 ) so that as a function of the data received and the management algorithms which it applies the processor transmits during the course of time command signals to the different organs—pumps, probes and valve—in order to control the temperature, the total pressure and the molar fluxes as a function of determined thermodynamic activity values.  
     
     
         7 . Reactor according to  claim 6 , characterized in that in a first stage designed to produce the gas mixture, liquid substrates ( 1 ), supplied from vats ( 2 ) are transported by pipework ( 3 ) towards the same mixer-injector ( 4 ) through dosage pumps ( 5 ) and a flux controller ( 6 ), and provision is also made for a source of vector gas ( 7 ) with its flow meter ( 8 ) to be optionally injected into the mixer ( 4 ); 
 in a second stage which concerns the reaction between the substrates, the substrate mixture is conducted from the injector ( 4 ) into the reactor proper ( 8 ) through a heat exchanger ( 9 ), the bioreactor containing an enzyme preparation, maintained at temperature.    in a third stage which relates to the control and analytical equipment, the vacuum pump ( 11 ) is coupled to the pressure control valve ( 12 ) and to a vacuum break detector, the post-reaction sampling chamber ( 14 ) being inserted into this outlet line by transfer with the aid of a pneumatically controlled multi-channel valve.    
     
     
         8 . Reactor according to  claim 6 , characterized in that the temperature control probes consist of thermocouples ( 15  to  18 ) and are distributed on the different organs, the pressure probe consists of a piezoresistive sensor ( 19 ), the set of temperature and pressure probes is connected to the controller ( 20 ) which regulates the vacuum regulation valve ( 12 ) in the bioreactor ( 8 ), this control being effectuated as a function of the data supplied by a microprocessor ( 21 ) in response to the data transmitted by the different probes and recorded by the microprocessor, the automation and regulation of the operating conditions as a function of the data received are ensured by an appropriate management algorithm.  
     
     
         9 . Reactor according to  claim 6 , characterized in that the mixer ( 4 ) comprises an ultrasonic head used as nebulizer in order to increase the exchange surface during the liquid-vapour flash, the analytical sampling of the gas phase at the bioreactor outlet of the bioreactor ( 8 ) is performed by means of a loop, then by injection onto a GC column for the determination of its composition, the detection being made by two sensors, one for water and one for all of the other organic molecules.  
     
     
         10 . Reactor according to any one of the  claims 6  to  9 , characterized in that the control of the different organs of the reactor is exercised by means of the microprocessor ( 21 ) coupled to the different probes and valves by a chart comprising A/D (analog/digital) conversion channels, 12 bits D/A conversion channels, and at least one signal in the TTL mode, and in that the management algorithm records at inlet the different temperatures measured, calculates the partial pressures and the reference saturation pressures in order to calculate the respective thermodynamic activities of the different substrates and delivers the instructions for the flow meters ( 6 ,  8 ) as well as for the vacuum regulation valve ( 12 ).  
     
     
         11 . Reactor according to any one of the  claims 8  to  10 , characterized in that double-panelled thermocouple conditioners give accuracies of temperature measurements of +/−0.1° C. over a range of 20 to 150° C., in that the accuracy of the entered and read-out values of the dosage pumps is +/−0.5% of the maximal capacity of the flow meters, that of the pressure measurements is +/−1 mbar so that the calculation of the saturation pressures made by linear regression of the exponential type provides values with a maximal absolute error of +/−5.10 −4  atm.  
     
     
         12 . Reactor according to any one of the  claims 6  to  10 , characterized in that the algorithm used defines and manages over time sequences of events ( 240  to  280 ) concerning the gas fluxes in order to vary the operating conditions programmable as vapour pressure or thermodynamic activity ( 210  to  230 ), manages the sample injection sequences into the analytical equipment ( 210 ,  220 ,  230 ,  240 ) and monitors in real time the control parameters in the reaction chamber ( 280 ,  240 )): inlet and outlet fluxes, partial pressures, molar flux and activity of each substrate and product, temperatures, residence times, for the initialization of the reactor ( 210 ,  250 ), the calibration of the processor reading chart ( 200 ), the access of the tables of events ( 211 ,  220 ,  230 ), the wait/start reaction mode ( 250 ,  260 ) and the end of reaction ( 300  to  323 ).  
     
     
         13 . Reactor according to any one of the  claims 6  to  12 , characterized in that for molecules difficult to condense, the addition of nitrogen or air is dispensed with as is the control valve upstream from the vacuum pump in order to minimize the dilution of the reaction products and to improve the efficiency of the condensation step, the control of the total pressure being made by a valve placed between the reactor and the vacuum pump and controlled by the pressure measurement made upstream from the reactor.  
     
     
         14 . Reactor according to any one of the  claims 6  to  13 , characterized in that in the case of molecules difficult to separate, a molecular filtration system is added at the condenser outlet and the use of a cryogenic fluid is dispensed with.  
     
     
         15 . Reactor according to any one of the  claims 6  to  14 , characterized in that a gas/gas pervaporation is coupled to the solid/gas biocatalysis to lead to an enrichment of molecules to be eliminated before their passage into the bioreactor.  
     
     
         16 . Reactor according to  claim 15 , characterized in that the evaporator is replaced by the permeate module of a pervaporation module and the permeate gas is introduced into the bioreactor by a gas pump serving as compressor, the pressure of the reactor being regulated by a flow restriction valve at the reactor outlet, the vacuum pump having been disconnected.  
     
     
         17 . Reactor according to  claim 16 , characterized in that a second pervaporation module is coupled to a cryogenic condenser or exchanger placed downstream from the flow restriction valve.  
     
     
         18 . Reactor according to any one of the  claims 6  to  17 , characterized in that in the case where the reaction product undergoes a change of state, a gas/solid or gas/liquid separator is added at the reactor outlet, only the gas phase being then recycled towards the gas pumping group by passage through a pressure condenser.  
     
     
         19 . Use of a reactor according to any one of the  claims 6  to  13  and  18  for the production of organic molecules such as alcohols, carboxylic acids, thiols, thioesters, esters, aldehydes, ketones, alkene oxides, lactones.  
     
     
         20 . Use of a reactor according to the  claim 19 , characterized in that the molecules produced can be used as flavours or fragrances.  
     
     
         21 . Use of a reactor according to any one of the  claims 6  to  18  for the biopurification of gas effluents.  
     
     
         22 . Use of a reactor according to any one of the  claims 6  to  18  for the production of biosensors specific for the detection of volatile molecules to form an artificial nose.  
     
     
         23 . Use of a reactor according to any one of the  claims 6  to  12  for the analysis of molecules obtained by means of a known analytical instrument by coupling of the reactor to this instrument.  
     
     
         24 . Use according to  claim 23 , characterized in that the reactor constitutes an enzymatic derivatization precolumn for the separation procedure used in gas chromatography (GC).