DUAL FUNCTION MULTIPHASE MICROREACTOR

FIELD OF INVENTION:

The invention relates to microreactor for conducting multiphase reaction. More specifically, the present invention provides a dual function multiphase microreactor having microfluidic flow design to carry out reaction involving an immiscible phases, preferably for at least two or three immiscible phases for example to carry out reaction involving in a phase transfer catalyst reaction. The said multiphase microreactor enables to carry out continuous multiphase reaction and simultaneously phase separation therein. Hence the said microreactor provides faster reaction rate, higher conversion rate, selectivity including separation and reusability of catalyst phase or any phases therein.

BACKGROUND OF THE INVENTION:

Multiphase reactions, such as liquid-liquid-liquid phase reactions in a tank reactor which are carried out at the interface of two immiscible liquids to form a new product can be advantageous in terms of improved reaction kinetics, higher yields, and selectivity. Such type of reactions is utilized in manufacturing of many agricultural chemicals, pharmaceuticals, and other specialty chemicals and intermediates. The presence of the liquid-liquid interface can accelerate the reaction, the interface between hydrophilic and hydrophobic liquids can be used to combine immiscible reaction partners or to protect sensitive partners, from hydrolysis for example or a phase-transfer catalyst is employed to draw the reaction in one phase of choice (liquid-liquid-liquid three phase reaction). There are many types of reactions that can be conducted at the interface of two immiscible liquids, either in a static environment or mechanically stirred, like nucleophilic substitution reactions, carbene formation, alkylations and alkoxylations, oxidations and reductions, and condensation, elimination, and addition reactions Three phase reactions, such as liquid-liquid-liquid (L-L-L) phase reactions wherein the phase transfer catalyst (PTC) is a special type of catalyst which enables the reaction in a heterogeneous system between general organic compounds soluble in upper layer organic solvents and compounds soluble in water in the bottom layer. Thereby, multiphase PTC reaction contain upper organic phase, middle catalyst rich phase and lower aqueous phase. The middle phase is the catalyst-rich phase, with two interfaces on either side, namely aqueous phase-middle catalyst phase and organic phase -middle phase. When the catalyst concentration is beyond a critical concentration, the formation of the middle phase occurred between the aqueous phase and organic phase. The formation and stability of the middle phase depend on the phase equilibrium-hydrophilic and lipophilic balance, density difference and temperature. The middle phase contains majority of the catalyst along with some of the organic solvent, aqueous nucleophile and trace quantity of water. Thus, the operating conditions for the formation of middle phase include type and quantity of phase transfer catalyst, type and quantity of aqueous reactants, reactant and product in organic phase, quantity of base, quantity of inorganic salts and reaction temperature. Some examples of liquid-liquid-liquid (L-L-L) phase reactions are described below.

Newmann et al. (1984) discovered role of polyethylene glycol as a phase transfer catalyst for the isomerization of allyl anisole under triphasic reaction conditions. They obtained three phase reaction mixture by using 60% aqueous KOH with toluene and catalytic amount of PEG-400. Weng et al. (1988) studied the role played by middle liquid phase in L-L-L phase transfer catalysis and observed that addition of phase transfer catalyst beyond a critical amount leads to a sharp increase in the reaction rate.

Yadav and coworkers studied several L-L-L PTC systems which include n- butoxylation of p-chloro-nitrobenzene (Yadav G.D. and Reddy C.A., 1999), alkylation of 2'-hydroxyacetophenone with l-bromopentane (Yadav G.D. and Desai N.M., 2006), synthesis of benzyl phenyl ether (Yadav G.D. and Badure O.V.,2007), synthesis of 3-(Phenyl methoxy)phenol from resorcinol and benzyl chloride (Yadav G.D. and Badure O.V., 2008), etherification of p-hydroxy- biphenyl with benzyl chloride to 1, 1 '-biphenyl -4-(phenyl methoxy) (Yadav G.D. and Badure O.V., 2008), Also various oxidation and reduction reactions have been explored such as oxidation of methyl mandelate to methyl phenyl glyoxalate (Yadav G.D. and Motirale B.G., 2010), reduction of 4-nitro-o-xylene by sodium sulphide to give 4-amino-o-xylene (Yadav G.D. and Lande S.V., 2007), selective reduction of substituted nitroaromatics (Yadav G.D. and Lande S.V., 2005).

As discussed in above prior arts, the phase transfer catalysis is conducted in dispersed-phase systems wherein a three-phase mixture containing a phase transfer catalyst or PTC is stirred vigorously in a tank or other vessel (Batch Reaction) to form an agitated interface or micro droplets dispersion. Typically, the overall rate of conversion initially increases with stirring speed, since increasing the stirring speed causes the formation of greater numbers of smaller drops with higher interfacial areas. Ultimately, however, the conversion rate plateaus with increased stirring speed, as the heterogeneous reaction system undergoes a transition from mass-transfer control to bulk organic -phase kinetic control.

Over the years, many attempts have been made to improve multiphase reaction rates with ease of recirculation of reaction phases. Substantial efforts have been made to use apparatus with continuous flow reactions or with small internal dimensions (microchannel) to increase the conversion rate of biphasic reactions including phase separation techniques like use of separation plates, hydrophilic/hydrophobic coating or membrane at the interfaces, once the reaction is completed and allowed to resides for phase separation.

US7,604,78l discloses multi-phase PTC reactions conducted in microchannel apparatus comprise of at least one separation assist feature selected from the group consisting of: an expansion zone in the separation zone that is connected to a reaction channel and has a larger internal cross-sectional area than the reaction channel, a phase coalescence element, and a separator plate. US 4,754,089 disclose a method for conducting phase transfer catalysis reaction in a multiphase reaction system wherein the different phases are separated by a membrane permeable to the phase transfer catalyst.

The problem identified by present inventor is difficulties in separation of active catalyst for reuse and therefore reaction cannot be performed continuously. Typical

PTC reaction of the interest is a displacement reaction. Under these conditions, much less than stoichiometric quantities of catalyst is utilized/deactivated, because the catalyst can continually shuttle back and forth between phases, carrying fresh reactant into the organic phase/aqueous phase with it. It is foreseeable in the practice of this invention that the phase transfer catalyst is active for longer time and can be utilized for continuous reaction processes even in micro reactor systems. Whereas, in plate separator or membrane separator forms available in prior art apparatuses, the catalyst recovering or separation from organic or aqueous phase is a major problem. Other disadvantages of available microreactor include small reaction path length. There is no single attempt is made to develop microreactor with separation of PTC catalyst from multiphase or liquid-liquid-liquid PTC reaction while performing continuous reaction.

In accordance with an aspect of the invention it is desirable to provide a dual function microreactor having microfluidic flow for multiphase reaction which provides long reaction path for continuous reaction and keeping reaction phases separated from each other to ensure more effective phase separation at the end of reaction treatment path for a given residence time. Also, the new reactor is successfully separating middle active catalyst phase and can be utilise without further post-treatment for recirculation to carry out new reaction, as middle phase is totally kept in between the organic and water phase thought out the reaction without disturbing the interfaces or forming droplets dispersion.

The discussion of documents, acts, materials, devices, articles and the like is included in this specification solely for the purpose of providing a context for the present invention. It is not suggested or represented that any or all of these matters formed part of the prior art base or were common general knowledge in the field relevant to the present invention as it existed before the priority date of each claim of this application.

OBJECTIVES OF THE INVENTION:

• The primary objective of the present invention aims to develop and design a microreactor for multiphase reaction involving a one or two immiscible phases.

• One more objective of the present invention is to provide a microreactor for reaction involving a phase transfer catalyst, wherein the reactor enables to conduct firstly the continuous chemical reaction instead of batch reaction and second, perform a phase separation simultaneously without stopping the reactor.

• Next objective of the present invention is to provide a microreactor for multiphase reaction which will reduce the impurity level in final product. · One more objective of the present invention is to provide a microreactor, that will keep the phase transfer catalyst active for longer time and can be utilized for continuous reaction processes or reuse for several cycles.

• Another objective of the invention is to continuously reuse middle catalyst phase without any treatment. Further another objective of the invention is to find out mass transfer coefficient of each phase.

• Yet another obj ective of the invention is to reuse aqueous phase, organic phase and/or catalyst phase.

SUMMARY OF THE INVENTION:

The present invention aims to provide a microreactor having microfluidic flow paths capable of performing multiphase reaction using two or more immiscible phases, wherein the said microreactor offers continuous process for such multiphase reactions and each phase is separated by permeable membranes so that to keep the phases separated throughout reaction. The present invention also aims to allow for continuous collection of each phase and recirculation of any one or all phases through same reaction device for reusability.

According to one aspect, the present invention provides a dual function, continuous flow microreactor device (100) for two/multiphase reaction comprising of:

- three plates stacked in layer, bottom (la), top (lb) and middle (lc) and having fluidic microchannel,

-two membranes (2a and 2b);

characterized in that when said three plates stacked in layer with at least one membrane sandwich between adjusting plates, defining:

а) a three-fluid path stacked in layer for each different chemical phases; providing a laminar flow of each phase flowing from inlet conduits (4, 5 and б) through the stacked paths separated by said membrane and coming out without mixing from outlet conduits (11, 15 and 19), allowing two phase transport of reactant and product via diffusion through membrane placed at phase interfaces and thereby increasing selective reaction and keeping phases separated while performing liquid-liquid-liquid, gas-liquid-liquid, fluid-liquid-liquid reaction.

According to another embodiment, this dual function microreactor is further configured to back pressure regulator (14, 18 and 22) to exert a pressure for diffusion through membrane.

Additionally, the shape of microchannels are provided in zic-zac or S-shape to cover maximum area of plate and maximum path length to increase residence time of reactant. The said plates are made from material selected from Polytetrafluoroethylene, stainless steel, glass, hastelloy and selection of membranes depend upon the hydrophilicity and lipophilicity of reacting molecule and product thereof. BRIEF DESCRIPTION OF DRAWINGS:

For a more complete understanding of the features and advantages of the present invention, reference is now made to the detailed description of the invention along with the accompanying figures and in which:

Figure No. 1: Schematic view of microcontroller showing various embodiment of it as per present invention.

Figure No. 2: Illustrated the view of the fluidic channels and flow inlet and outlet itched on plain surface of top (lb), middle (lc) and bottom (la) plate.

Figure No. 3: Illustrated the (a) cross-view of the fluidic channels on plain surface of top (lb), bottom (la) plate and (b) cross-view of the fluidic channels on plain surface of middle (lc).

Figure No. 4: Depict cross section view of microreactor as per present invention. Figure No. 5: Schematic view of a reaction unit including layering of plurality of plates and membranes.

Figure No. 6: Depict a phase transfer reaction having transfer of reactant, product and catalyst molecular involved in phase transfer reaction as discussed in example 1

DESCRIPTION OF THE INVENTION:

While the making and using of various embodiments of the present invention are discussed in detail below, it should be appreciated that the present invention provides many applicable inventive concepts that can be embodied in a wide variety of specific contexts. The specific embodiments discussed herein are merely illustrative of specific ways to make and use the invention and do not delimit the scope of the invention.

To facilitate the understanding of this invention, a number of terms are defined below. Terms defined herein have meanings as commonly understood by a person of ordinary skill in the areas relevant to the present invention. Microreactor offers many advantages over batch reactor which include suitability for handling hazardous reactions because of vastly reduced hold-up of dangerous reactants and solvents. Mixing is done by diffusion which is very fast comparing to achieve by turbulence in a batch reactor. High surface to volume ratio of microreactor gives much better heat exchange capability and is highly suitable for exothermic and runaway type of reactions. By numbering -up microreactor units on demand production and portability can be easily achieved.

Accordingly, the present invention provides a dual function multiphase microreactor with continuous flow mechanism for carrying out at least three liquid phase chemical reaction having three fluidic channels for each phase with at least two membrane separator sandwiches between three fluidic channels to ease of phase separation.

Hence, in present invention of dual function microreactor, the reaction and phase separation occur simultaneously.

With reference to the figure no. 1, the present invention provides a dual function, continuous flow microreactor device (100) for two/multiphase reaction comprising of:

- three plates stacked in layer, bottom (la), top (lb) and middle (lc) and having fluidic microchannel, wherein each plate is having plurality of notches configured to fasten,

-two membranes (2a and 2b) disposed at the phase interfaces;

characterized in that when said three plates stacked in layer with at least one membrane sandwich between adjusting plates, defining:

а) a three-fluid path stacked in layer for each different chemical phases; providing a laminar flow of each phase flowing from inlet conduit (4, 5 and б) through the stacked paths separated by said membrane and coming out without mixing from outlet conduits (11, 15 and 19), allowing two phase transport of reactant and product via diffusion through membrane placed at phase interfaces and thereby increasing selective reaction and keeping phases separated while performing liquid-liquid-liquid, gas-liquid-liquid, fluid-liquid-liquid reaction.

Further, the present invention provides a microreactor device (100) for three phase reaction comprising

-two plates stacked in layer, top (lb) and bottom (la) plates having fluidic microchannel, wherein each plate is having plurality of notches configured to fasten,

-a membrane (2a) disposed at the phase interface;

characterized in that when said two plates stacked in layer with membrane sandwich between top and bottom plates, defining:

a) a two separate fluid path stacked in layer for two immiscible phases providing a laminar flow of each phase flowing from inlet conduit (4, 6) through the stacked paths separated by said membrane and coming out without mixing from outlet conduits (11, 19), allowing two phase transport of reactant and product via diffusion through membrane placed at phase interface and thereby increasing selective reaction and keeping phases separated while performing liquid-liquid, gas-liquid, fluid-liquid phase reaction. The each plate is having plurality of notches configured to fasten each plate together.

The said reactor is further configured to back pressure regulator (14, 18 and 22) to exert a pressure for diffusion through membrane.

With reference to the figure no. 2, top (lb), middle (lc) and bottom (la) plates are having microchannels disposed on plain surface. In preferred embodiment and with referring to accompanied figure no. 3 (a), the fluidic microchannel disposed on bottom plate (la) and top plate (lb) is semi circular half-channel with one side open on plain surfaces. Whereas, as shown in figure no. (3b) fluidic microchannel disposed on middle plate (lc) is open channel with both side open on plain surfaces.

In accordance to one of the embodiment, the channel/groove is prepared isotropically etching into a flat substrate, resulting in a semi-circular half-channel or Open channel (or a rectangle with rounded comers) having width in the range from 0.1 to 1000 pm. The material of plates are selected from Polytetrafluoroethylene and stainless steel, glass, quartz, hastelloy. The term “groove,” as used herein, should be understood to mean a surface feature that has been formed into the surface of an object, that does not penetrate completely through the object, and applies to components of prior art chemical reactors.

Additionally, the plates having openings at both the end (4’, I F, 5’, 15’, 6' and 19’) of microchannel therein for circulation of reaction phase from one end to another end.

The microchannels are provided in S-shape or any other suitable curves to cover maximum area on plates and maximum path length to increase residence time of reactant.

With reference to the figure no. 4, referring the cross section view of microreactor wherein the said microreactor plates and each plate is having plurality of notches (7) configured to fasten each plate together in layer and touching each other the plates having no openings/space therein for circulation or mixing of any phase flowing through each plate’s microchannel.

A key feature of the present invention is the stacking of three plates and two membranes. For example, the manner in which the simple plates are joined together are important aspects of the present invention. The openings in each plates in accord with the present invention are configured and oriented to manipulate a laminar flow of fluid in three stacked microchannels in a reactor to achieve a desired result. Preferably the manipulation will result in an enhancement of a quantity or a quality of a chemical product produced in Such a reactor. Additional product can be generated by a phase transfer phenomenon while reacting in multiphase reaction by including a passage to reacting molecule from one phase to other phase / from top and bottom phase to middle phase by permeable membranes disposed at the phase interphases that define a selectivity of product in a reaction channels. Higher levels of product can be produced by including more path length or by controlling pressure of fluids to optimise a diffusion rate.

With referring to figure no. 5, a view of plurality of stacked plates and membranes sandwich between two adjacent plate, the said membranes are having selective permeability to molecules selected from hydrophobic and hydrophilic, that enable a reactor to exchange of reactant and product from one phase to other phase or enables selectively transfer of one reaction molecule from between the phase interphases. The type pf membranes are selected and not limiting to hydroxylated nylon and polytetrafluoroethylene. And group of ceramic membrane, stainless steel membrane, metal oxide membrane. Additional sealed interfaces that would otherwise be presented if tubing, connectors, valves or other fluid handling hardware are possibly couple the fluidic microstructures or conduits thereof.

Further, the present invention is related to dual function microreactor to carry out multiphase PTC reaction accomplished by membrane for phase separation and pumps for recirculation of all phases including catalyst phase. The present invention allows continuous reuse of catalyst without any disturbance or shutdown of the process.

The present invention focuses on the design and development of novel dual functional microreactor which has been used to intensify chemical processes by synergistically combining chemical reaction with phase separation for multiphase PTC reactions. The dual functional microreactor has the additional benefit of enhancing the selectivity of the desired product through manipulation of various parameters such as flow rate, mole ratio and temperature. In accordance to one of the embodiment, the present invention provides a method of operating the dual function microreactor (100) as illustrated accompanied herewith.

The method comprises of following steps:

a) Preparation of three phase mixture in the reservoir by addition of water, aqueous phase reactant, base, inorganic salt, catalyst and organic solvent along with organic phase reactant,

b) Run the phases in the respective microchannel with the help of pumps wherein the three outlets of the micro-reactor were connected to separate inlet of the back pressure regulator (BPR) to control the residence time of reactant in reaction chamber.

c) Collection an aqueous, organic and catalyst phases separately in reservoir or recirculation of phases from the outlet of respective BPR back to reactor inlets. A technical advantage of the present invention includes micro-reactor with membranes for simultaneous reaction and separation of three phases. Another advantage includes higher conversion and selectivity, in shorter periods of time, compared to batch process. The middle catalyst phase is collected separately which can be continuously reused without any treatment. The aqueous phase is also reused after making up reactant concentration with fresh reactants.

The following but not limiting, the disclosure gives the parameters of a specific reactor which may be constructed in accordance with the present invention.

The lower aqueous phase is selected from group of aqueous phase reactant, base, inorganic salt, small amount of catalyst and water. Base used is any water soluble alkali preferably sodium hydroxide (NaOH), potassium hydroxide (KOH) and inorganic salt like sodium chloride (NaCl), sodium bromide (NaBr), potassium chloride (KCl)and potassium bromide (KBr). The upper organic phase is selected from group organic phase reactant, organic solvents. Solvent should be immiscible preferably toluene, cyclohexane and 1- chlorooctane.

The middle catalyst phase is selected from group ammonium salts like tetra butyl ammonium bromide (TBAB), tetra methyl ammonium bromide (TMAB), butyl triethyl ammonium chloride (BTEAC1), Polyethylene glycol (PEG3000-20000), crown ether, phosphonium salts like ethyl triphenylphosphonium bromide (ETPB), Tetra Phenyl Phosphonium Bromide(TPPB) are used as phase transfer catalyst.

The reactor disclosed in the present invention can be useful to conduct various PTC reactions in micro channels like displacement reaction, C-alkylation reaction, O- alkylation reaction, N-alkylation reaction, S-alkylation reaction, oxidation reaction, reduction reaction, isomerization reaction, dehydrohalogenation reaction etc.

The continuous flow is achieved by means of controlling pump operated to feed aqueous, organic and catalyst phase. Hence flow rate and back pressure regulators are adjusted in such way that it maintains all three phases in parallel flow and pressure difference gradient condition.

The economic potential of the present invention includes continuous reuse catalyst without any treatment and continuous process for conducting multiphase PTC reaction at volume of micro litre level. It should be understood that the invention is not restricted to the embodiment which has been described herein but covers all variants immediately accessible to a man skilled in the art. In particular, the method and the installation according to the invention can be used for the carrying out of any two or more phase chemical reaction under pressure in the presence of a gas phase, a liquid phase and a third phase which may, according to the case, be a liquid or a solid or slurry containing fine particles. In addition, the hydrophilic or hydrophobic can be placed at the interface of liquid phase if desired for particular reaction. The foregoing and other aspects of the invention are achieved in combination. The invention should not be construed as requiring two or more of the such aspects unless expressly required by a particular claim. Moreover, while the invention has been described in connection with what is presently considered to be the preferred examples, it is to be understood that the invention is not limited to the disclosed examples, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and the scope of the invention.

Examples:

There is a limitation on the size of the droplets while performing L-L-L multiphase/PTC reaction and hence resulting into limitation on mass transfer coefficients and rates. The microreactor as claimed in present invention was suitably used to overcome this problem and the mass transfer coefficients can be independently controlled by independently controlling flow in the channels and selecting a specific membrane polarity for interested product or to reduce the impurity.

The dual functional microreactor has additional benefit of enhancing the selectivity of the desired product through manipulation of various parameters such as catalyst quantity, flow rate, mole ratio and temperature.

Example 1:

An accompanied Figure 6 illustrated the cross sectional view of micro reactor, wherein the dual functional microreactor which simultaneously perform multiphase reaction as well phase separation comprises of three fluidic channels for organic (Channel A), middle PTC catalyst phase (Channel B) and aqueous phase (Channel C). Further, it comprises at least two membranes E and F having hydrophilic or hydrophilic properties. The said membranes are sandwich between adjacent phases. More preferably, hydrophilic membrane is sandwich between the aqueous phase and the catalyst phase channel and a hydrophobic membrane is sandwich between the organic phase and catalyst phase channel. The material of construction of channel is preferably selected from Polytetrafluoroethylene (PTFE), Polyether ether ketone (PEEK) or stainless steel.

This example illustrates the study of L-L-L PTC alkylation reaction (scheme I) of sodium p-methoxy phenate with allyl bromide in a novel microreactor.

The reaction of p-methoxyphenol and allyl bromide under basic conditions leads to the formation of O- and C-alkylated derivatives, namely, l-methoxy-4-(2- propenyloxy)benzene, 4-methoxy-2-(2propenyl)phenol, and l-allyloxy-2-allyl-4- methoxy benzene. The objective of this work was to suppress the formation of byproducts and achieve 100 % selectivity towards l-methoxy-4-(2-propenyloxy) benzene, which is a valuable perfume. Another objective was to find process conditions to increase selective towards the C-alkylated product, 4-methoxy-2-(2- propenyl) phenol which also has perfumery value by using dual function microreactor as per present invention.

A. Microreactor setting:

The hydrophilic and hydrophobic membranes were specially prepared. The thickness of hydrophilic membrane was 100 pm with pore size of 0.1 pm. The thickness of hydrophobic membrane was 100 pm with pore size of 0.2 pm. The volume and length of the top and bottom channels were 8.27 pl and 11.82 cm respectively. The volume and length of the middle channel were 10.1 pl and 14.43 cm respectively.

The experimental setup as per present invention contains three pumps from which the three different phases were pumped and fed directly into the three inlet ports of the microreactor. The three outlets of the microreactor were fed into the inlet of back pressure regulator (BPR) of pressurization module and the outlet of the BPR in turn was fed into the collection module.

BPR ensure good separation of phases by maintaining pressure across the membranes. B. Phase Separation:

As shown in scheme II, in L-L-L PTC reaction, a separate catalyst-rich middle phase is created, which is the main locale of the reaction into which both aqueous and organic phase reagents are transferred from the two interfaces. This phase not only intensifies the rates of reaction but also improve the selectivity of the desired product, leading to economic and environmental benefits.

C. Synthesis of l-methoxy-4-(2-propenyloxy) benzene

When the catalyst concentration was beyond a critical concentration, the formation of third phase (scheme II) occurred between the aqueous phase, which was saturated with sodium chloride and organic phases of toluene as solvent. Typical reactions were conducted in microreactor with 0.025 mol allyl bromide, 0.0125 mol n-undecane as internal standard dissolved in toluene with 0.013 mol TBAB as the catalyst to make the volume of organic phase to 50 cm ³ and 0.05 mol p-methoxy phenol, 0.05 mol sodium hydroxide and 0.26 mol sodium chloride were dissolved in water to make up volume of aqueous phase to 50 cm ³ for the production of 100% selective towards l-methoxy-4-(2-propenyloxy) benzene. The three phases were separated and pumped to the microreactor separately and a typical reaction was conducted at 25°C, flow rate of the organic and aqueous phase were 30 pl/min and that of middle phase was 20 mΐ/min, pressure across the hydrophilic and hydrophobic membranes were 480 mbar and 460 mbar respectively. Three phases were pumped independently and the catalyst rich middle phase, which was coming out of the pressurization module, was recirculated back to the feed vessel of the middle phase. Sample analysis was done by GC.

D. Synthesis of 4-methoxy-2-(2-propenyl) phenol

When the catalyst concentration was beyond a critical concentration, the formation of third phase (Scheme II) occurred between the aqueous phase, which was saturated with sodium chloride and organic phases of toluene as solvent. Typical reactions were conducted in microreactor with 0.0167 mol allyl bromide, 0.0125 mol n-undecane as internal standard dissolved in toluene with 0.013 mol TBAB as the catalyst to make the volume of organic phase to 50 cm ³ and 0.05 mol p-methoxy phenol, 0.05 mol sodium hydroxide and 0.26 mol sodium chloride were dissolved in water to make up volume of aqueous phase to 50 cm ³ for the production of more selective towards 4-methoxy-2-(2-propenyl) phenol. The three phases were separated and pumped to the microreactor separately and a typical reaction was conducted at 25°C, flow rate of the aqueous phase was 250 mΐ/min, middle phase was 250 pl/min, and organic phase 10 pl/min. Pressures across the hydrophilic and hydrophobic membranes were 480 and 460 mbar, respectively. Three phases were pumped independently and the catalyst rich middle phase, which was coming out of the pressurization module, was recirculated back to the feed vessel of the middle phase. Sample analysis was done by GC.

Table no. 1