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Title:
CURABLE LIQUID RESIN COMPOSITION
Document Type and Number:
WIPO Patent Application WO/2003/074579
Kind Code:
A1
Abstract:
A conventional curable liquid resin composition comprising (a) a urethane (meth)acrylate, and (c) a phosphorus-containing photoinitiator, can show haze after aging and other changes in properties upon aging. The present invention provides a solution to that problem by using (b) a Group IV metal compound in the synthesis of the urethane acrylate. The curable liquid resin composition of the present invention excels in high-speed curability and produces a uniform and transparent cured product. The present invention provides an optically uniform and highly transparent coating material for optical fibers, and a surface coating material and adhesive for various types of optical components.

Inventors:
SUGAWARA SHUICHI (JP)
SUGIMOTO MASANOBU (JP)
KOMIYA ZEN (JP)
NORIKO ABE (JP)
Application Number:
PCT/NL2003/000149
Publication Date:
September 12, 2003
Filing Date:
February 27, 2003
Export Citation:
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Assignee:
DSM NV (NL)
SUGAWARA SHUICHI (JP)
SUGIMOTO MASANOBU (JP)
KOMIYA ZEN (JP)
NORIKO ABE (JP)
International Classes:
C08F2/50; C03C25/10; C08F4/16; C08F283/00; C08F290/06; C08F299/06; C08G18/22; C08G18/67; C09D175/16; (IPC1-7): C08F299/02; C03C25/10; C08F4/16; C08F230/06; C08G18/67; C09J175/16
Domestic Patent References:
WO2001083393A22001-11-08
Foreign References:
US4894356A1990-01-16
US5859087A1999-01-12
Attorney, Agent or Firm:
Den Hartog J. H. J. (P.O. Box 9, MA Geleen, NL)
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Claims:
What is Claimed
1. A device for inducing turbulence in the flow of a fluid in the course of a continuous flow process, the device comprising: a plurality of chambers, each chamber having a central conduit section extending from an inlet section to an outlet section, the inlet section having a shape that progressive¬ ly reduces the velocity and pressure of fluid flowing through it, the central section having a shape that tends to maintain constant the pressure and velocity of fluid flowing through it, the outlet section having a shape that progres¬ sively increases the pressure and velocity of fluid flow ing through it; with respect to each pair of the plurality of chambers, the outlet section of the upstream chamber being connected to the inlet section of the downstream chamber in a manner such as to maintain turbulence in fluid flowing through the device.
2. A device as set forth in Claim 1 wherein: the shape of the inlet section and the shape of the outlet section of each chamber cause respective de¬ creases and increases in pressure and velocity to be exponential.
3. A device as set forth in Claim 2 wherein: the central section of each chamber has a length extending from the inlet section to the outlet section of the chamber and, with respect to each pair of chambers, the outlet section of the upstream chamber is connected to the inlet section of the downstream chamber by a con¬ duit no longer than about half the length of the central section.
4. A device as set forth in Claim 2 wherein: the central section of each chamber has a length extending from the inlet section to the outlet section of the chamber, the chambers are arranged coaxially along a central axis and, with respect to each pair of the plu¬ rality of chambers, the outlet section of the upstream chamber is contiguous with the inlet section of the down¬ stream chamber.
5. A device as set forth in Claim 1 wherein: the number of pairs is from one to about eleven.
6. A device as set forth in Claim 4 wherein: the inlet section of each chamber has an inlet and has an outlet contiguous with the upstream end of the central section, and the outlet section of each chamber has an inlet contiguous with the downstream end of the central section and has an outlet of crosssectional area substantially equal to that of the inlet of the inlet section.
7. A device as set forth in Claim 6 wherein: the central section of each chamber is of substan¬ tially constant cross section.
8. A device as set forth in Claim 7 wherein: substantially all crosssections through the inlet, outlet and central sections are substantially cir¬ cular.
9. A device as set forth in Claim 8 wherein: the inlet and outlet sections of each chamber are frustoconical.
10. A device as set forth in Claim 9 wherein: the inlet section and the outlet section of each chamber has an internal surface that has a slope with respect to the axis of from about 15° to about 60°.
11. A device as set forth in Claim 10 wherein: the central section of each chamber is a cylinder of constant diameter and the inlet of the inlet section and the outlet of the outlet section of each chamber are of substantially equal circular crosssections that are from about 0.2 to about 0.5 times the constant diameter of the central section.
12. A device as set forth in Claim 11 wherein: the length of the central section of each chamber is in the range of from about equal to the reduced dia¬ meter of the inlet of the inlet section of the chamber to about five times the constant diameter of the central section of the chamber.
13. A device as set forth in Claim 12 wherein the chambers are enveloped in a heat transfer means.
14. A method for reacting fluent materials in a continuous flow process comprising: (1) injecting the materials into a device at a flow rate sufficient to create turbulence, the device comprising: a plurality of chambers, each chamber having a central conduit section extending from an inlet section to an outlet section, the inlet section having a shape that progressive ly reduces the velocity and pressure of fluid flowing through it, the central section having a shape that tends to maintain constant the pressure and velocity of fluid flowing through it, the outlet section having a shape that progres¬ sively increases the pressure and velocity of fluid flow¬ ing through it; with respect to each pair of the plurality of chambers, the outlet section of the upstream chamber being connected to the inlet section of the downstream chamber in a manner such as to maintain turbulence in fluid flowing through the device; and (2) effecting a chemical reaction of the materials as they flow through the device.
15. A method as set forth in Claim 14 wherein: the shape of the inlet section and* the shape of the outlet section of each chamber cause respective de¬ creases and increases in pressure and velocity to be exponential.
16. A method as set forth in Claim 15 wherein: the central section of each chamber has a length extending from the inlet section to the outlet section of the chamber and, with respect to each pair of chambers, the outlet section of the upstream chamber is connected to the inlet section of the downstream chamber by a con¬ duit no longer than about half the length of the central section.
17. A method as set forth in Claim 16 wherein: the chambers are arranged coaxially along a cen¬ tral axis and, with respect to each pair of the plurality of chambers, the outlet section of the upstream chamber is contiguous with the inlet section of the downstream chamber.
18. A method as set forth in Claim 17 wherein: the inlet section of each chamber has an inlet and has an outlet contiguous with the upstream end of the central section, and the outlet section of each chamber has an inlet contiguous with the downstream end of the central section and has an outlet of crosssectional area substantially equal to that of the inlet of the inlet section.
19. A method as set forth in Claim 18 wherein: each of the inlet section and the outlet section of each chamber has an internal surface that has a slope with respect to the axis of from about 15° to about 60°.
20. A method as set forth in Claim 19 wherein: the central section of each chamber is a cylinder of constant diameter and the inlet of the inlet section and the outlet of the outlet section of each chamber are of substantially circular crosssection of a reduced diameter that is from about 0.2 to about 0.5 times the constant diameter of the central section.
21. A method as set forth in Claim 20 wherein: the length of the central section of each chamber is in the range of from about equal to the reduced dia¬ meter of the inlet of the inlet section of the chamber to about five times the constant diameter of the central section of the chamber.
22. A method as set forth in Claim 21 wherein: the chambers are enveloped in a heat transfer means, and heat transfer is effected between the heat trans¬ fer means and the materials as they flow through the device.
23. A method as set forth in Claim 18 wherein: the axis is generally horizontal.
24. A method as set forth in Claim 18 wherein: the axis is generally vertical.
25. A method as set forth in Claim 24 wherein: the device is oriented such that the inlet section of each chamber is below the outlet of the chamber and the materials are directed upwardly through the device. 26• A method as set forth in Claim 14 wherein: the materials are injected at a rate such that the materials pass through the reduced diameters of the inlet of the inlet section of each chamber at a linear flow rate of at least about 0.
26. 5 meters per second.
27. A device for inducing turbulence in the flow of a fluid in the course of a continuous flow process, the device comprising a series of chambers extending along an axis, each chamber being defined by: a conduit of at least substantially cylindrical form having a length extending along the axis and between opposite ends; a generally frustoconical diffuser having an internal crosssection increasing along the axis from a reduced internal crosssection at an inle of the dif¬ fuser to an internal crosssection substantially equal to that of the conduit at an outlet of the diffuser; and a generally frustoconical confuser having an internal crosssection decreasing along the axis from an internal crosssection substantially equal to that of the conduit at an inlet of the confuser to a reduced cross section at an outlet of the confuser; the conduit, diffuser and confuser of each chamber being arranged coaxially, the conduit extending from the outlet of the diffuser to the inlet of the confuser, the outlet of one confuser and the inlet of one diffuser of adjacent chambers in the series being connected together to maintain the adjacent chambers in fluid communication therebetween in a manner such as to maintain turbulence in fluid flowing through the device.
28. A device as set forth in Claim 27 wherein: the conduit of each chamber has a length extend¬ ing from the diffuser to the confuser section of the chamber and, with respect to each pair of adjacent cham bers, the outlet of one confuser and the inlet of one diffuser of adjacent chambers in the series are connected together, yet spaced apart by no more than about half the length of the conduit.
29. A device as set forth in Claim 27 wherein: the conduit of each chamber has a length extending from the diffuser to the confuser section of the chamber and, the chambers are arranged coaxially along a central axis and, with respect to each pair of the plurality of chambers, the outlet section of the upstream chamber is contiguous with the inlet section of the downstream cham¬ ber.
30. A device as set forth in Claim 29 wherein: the diffuser, confuser and conduit of each chamber are each of circular crosssection.
31. A device as set forth in Claim 30 wherein: each diffuser and each confuser is substantially frustoconical and has an internal surface that has a slope with respect to the axis of from about 15° to about 60°.
32. A device as set forth in Claim 31 wherein: the diameters of the reduced crosssections of the inlet of the diffuser and the outlet of the confuser of each chamber are from about 0.2 to about 0.5 times the diameter of the conduit of the chamber.
33. A device as set forth in Claim 32 wherein: the length of the conduit of each chamber is in the range of from about equal to the diameter of the reduced crosssection of the diffuser of the chamber to about five times the diameter of the conduit.
34. A device as set forth in Claim 33 having two to about twelve chambers.
35. A device as set forth in Claim 27 wherein: the chambers are enveloped in a heat transfer means.
36. A method for mixing fluent materials in a continuous flow process, the method comprising: directing a flow of the materials into a first zone of a first chamber of a static mixer; initiating a vortex in the flow of the materials in the first zone wherein the pressure and velocity of the flow progressively decreases; allowing the vortex to develop and to increase in intensity in a second zone of the first chamber wherein the pressure and velocity of the flow remain generally constant, the second zone being contiguous with the first zone; increasing the pressure and velocity of the flow in a third zone of the first chamber contiguous with the second zone; and directing the flow to a second chamber wherein a new vortex in the flow is initiated while turbulence resulting from the preceding steps remains in the flow, the vortex is allowed to develop in intensity and the pressure and velocity of the flow then is increased.
37. A method of inducing turbulence in the flow of a fluid comprising the steps of: imparting continuous flow to the fluid; progressively reducing the velocity and pressure of the fluid; directing the fluid to reduced pressure and velo¬ city through a conduit of substantially uniform cross section throughout a predetermined length; thereafter progressively increasing the velocity and pressure of the fluid; and thereafter repeating the foregoing steps in the foregoing order.
Description:
METHOD AND APPARATUS FOR MIXING FLUIDS Background of the Invention

(1) Field of the Invention

The present invention relates to microreactors, heat exchangers and mixers, and more particularly to apparatus and methods that utilize continuous flow tech- niques to induce substantial turbulence within the flow stream to provide a very high degree of mixing and/or heat transfer.

(2) Description of the Prior Art

A number of mixer designs have been employed in a variety of applications to mix fluent materials. Such applications include those in which it is desired to form an intimate mixture of two or more components, to form an emulsion, to cool or to heat a fluid, or to carry out chemical reactions. For example, in many chemical reac- tions mixing is desirable or necessary to introduce kine¬ tic energy or to bring reactant molecules into reactive proximity to each other. This is especially desirable in many polymerization reactions in which repeated introduc¬ tion of fresh reactants to the newly-created reaction

sites of the burgeoning polymer is necessary to continue the chain formation. The increased exposure of reactants to each other can also be effective in increasing yield and reducing reaction times, permitting higher production rates and smaller reactors. Thus, in many reactions, the rate of chemical reaction is related to the rate of mix¬ ing of the reactants.

In addition or in the alternative, heat transfer into or out of a fluid may also be enhanced by mixing.

In such situations, the turbulence constantly exposes new or other portions of the fluid to the interface at which heat transfer takes place. This is helpful in maintain¬ ing isothermal conditions, which can be particularly useful in many reactions, such as exothermic or endother- mic reactions or reactions that must be carried out with¬ in a narrow temperature range. For example, hyperfast, low temperature polymerization must be carried out with significant agitation and at substantially isothermal conditions in order to produce a polymer of molecular weights within a narrow range.

Turbulence may be induced in continuous flow processes by static means, which affect the flow of a fluid through the mixer or reactor, or by moving agita- tors. Static mixers provide a number of advantages over mixers that contain a moving agitation means. For exam¬ ple, because separate mechanical agitation means are unnecessary, static mixers generally are lower cost and require less maintenance. In addition, they are less expensive to operate because they do not require energy input for agitation.

On the other hand, conventional static mixers also suffer from several disadvantages over mixers that employ mechanical agitation means. Perhaps most prominent of these disadvantages is the generally lower degree of agitation or turbulence produced by conventional static mixers. Thus, relatively large mixers or reactors are

often needed. Moreover, the disadvantage of the less intense agitation is particularly pronounced in some applications in which even mixers with moving agitation means often do not create as much turbulence as desired. Aside from the failure to achieve the full measure of benefits associated with high turbulence as discussed above, the relatively low turbulence,produced by many conventional mixers that are coupled with a heat transfer means requires the use of small conduits to increase transfer. The use of such conduits not only is expen¬ sive, but requires higher pressures to maintain accept¬ able flow rates.

Accordingly, a variety of mixer designs have been created in an attempt to combine the benefits of static mixers with the ability to achieve a degree of turbulence at least as great as, and perhaps even greater than, that of mixers that have moving agitators. Such static mixers typically employ such means as baffles or a series of segments of increased and decreased cross-sectional areas to induce turbulence in the flow of the fluid or combina¬ tion of fluids, thereby to promote mixing.

For example, continuous flow polymerization reac¬ tors, some of which have a series of such segments, are shown in U.S. patents 3,609,125 and 3,697,230 to Yoshi- hisa Fujimoto et al. which disclose an apparatus which induces mixing not by expansion or contraction of the fluid path but by directing the fluid in a swirling motion, 3,628,918 and 4,175,169 to Beals et al. which show a polymerization reactor of alternating reaction and cooling zones wherein the mixing is accomplished by tur¬ bulent flow through constant diameter sections of tubing, and 3,674,740 to Vernaleken et al. which is directed to production of polycarbonate by what appears to be mere conventional flow through constant diameter tubes at a rate which associated with turbulent flow; i.e., a Rey¬ nolds number in excess of 2,000. U.S. patent 3,563,710

to Dew, Jr. et al. shows a finisher for removal of vola¬ tile by-products in carrying melt condensation polymeri¬ zation to completion. However, the apparatus of Dew, Jr. et al. does not mix by expanding and contracting the cross-sectional area of the flowing fluid along the length of the mixer. Rather, it induces turbulence by a swirling motion of the mixture about rotor members iden¬ tified in the patent by the numeral 2.

Various heat transfer apparatus that include sections of increased and decreased cross-sectional areas have been shown, for example, in U.S. Patents 1,863,554; 4,270,601; 4,306,617; 4,437,513; 4,569,387 and 4,633,935. Of course, in heat transfer apparatus, alternating sec¬ tions of increased and decreased cross-sectional areas, created such as by the use of corrugated tubing, is gene¬ rally known to be employed simply to increase surface area thereby to effect greater heat transfer. In such apparatus, the changes in the cross-sectional area gene- rally are insufficient to develop an optimal degree of turbulence in the fluid passing therethrough.

Other references are directed to apparatus which have decreased cross-sectional areas in the form of ori¬ fices through which a fluid passes. In particular, U.S. Patent 2,312,639 shows a device for treating plastic. The plastic is passed through a plate having a number of perforations to increase the surface area of a mass of plastic. A significant degree of mixing does not appear to be imparted thereby to the highly viscous plastic. U.S. Patent 4,313,680 shows a reactor for fast reaction which a flow-deflector is included to deflect the flow 90° through several orifices.

U.S. Patent 3,874,643 discloses a method for conveying pulverulent or granular thermoplastic or ther- mosetting material while simultaneously plasticizing., mixing and homogenizing the material by passing it

through a plasticizer having alternately narrow and wide tubular passages interconnected by conic sections.

U.S. Patents 4,964,733 and 4,861,165 show a gene¬ rally tubular hydrodynamic mixer having no cylindrical sections. According to these patents, the device is de¬ signed for a number of substances and applications in the paper industry are contemplated.

In any event, mixers are still being sought that can achieve even more intense turbulence than possible with conventional apparatus, particularly for continuous flow operations. It is also highly desirable that such improved turbulence be achieved by a static mixer, espe¬ cially one of relatively small size. Summary of the Invention Briefly, therefore, the present invention is directed to a novel device for inducing turbulence in the flow of a fluid in the course of a continuous flow pro¬ cess. The device comprises a plμrality of chambers, each of which has a central conduit section extending from an inlet section to an outlet section. The inlet section has a shape that progressively reduces the velocity and pressure of fluid flowing through it, the central section has a shape that tends to maintain constant the pressure and velocity of fluid flowing through it, and the outlet section has a shape that progressively increases the pressure and velocity of fluid flowing through it. With respect to each pair of the plurality of chambers, the outlet section of the upstream chamber is connected to the inlet section of the downstream chamber in a manner such as to maintain turbulence in fluid flowing through the device.

Thus, in a particular embodiment, the device com¬ prises a series of chambers extending along an axis. Each chamber is defined by (1) a cylindrical conduit that extends along the axis and between opposite ends and has a constant internal diameter along the axis; (2) a frus-

to-conical diffuser that has an internal diameter incre¬ asing along the axis from a reduced internal diameter at an inlet of the diffuser to an internal diameter substan¬ tially equal to that of the conduit at an outlet of the diffuser; and (3) a frusto-conical confuser that has an internal diameter decreasing along the axis from an in¬ ternal diameter substantially equal to that of the con¬ duit at an inlet of the confuser to a reduced diameter at an outlet of the confuser. The conduit, diffuser and confuser of each chamber are arranged coaxially and the cylindrical conduit extends from the outlet of the dif¬ fuser to the inlet of the confuser. The outlet of one of the confusers and the inlet of one of the diffusers of adjacent chambers in the series connect the chambers together.

The present invention is also directed to a novel method for mixing fluent materials in a continuous flow process by injecting materials into such device. The process may be used, for example, to form mixtures or emulsions, to improve heat transfer or to aid in effect¬ ing chemical reactions.

Among the several advantages found to be achieved by the present invention, therefore, may be noted the provision of a continuous flow static mixer that provides more intense mixing than achieved by conventional de¬ vices; the provision of such mixer that is relatively inexpensive to manufacture; the provision of such mixer that permits improved heat transfer; the provision of such mixer that enables better control of temperature throughout the fluids being treated; the provision of such mixer that enables improved control of reactions carried out therein; the provision of such mixer that is of relatively small size; the provision of a method for improved mixing of fluent materials through a static mixer; the provision of such method which provides im¬ proved heat transfer; the provision of such method which

provides improved control of temperature throughout the material being treated; and the provision of a method of improved control of many types of reactions. Brief Description of the Drawings Figure 1 is a cross-sectional view of a re¬ action/mixer of this invention. Description of the Preferred Embodiments

In accordance with the present invention, it has been discovered that superior mixing, heat transfer and temperature uniformity can be achieved in a continuous flow process by injecting fluent materials into and through a device comprising a series of juxtaposed cham¬ bers, each of which is defined by a cylindrical conduit extending from a frusto-conical diffuser to a frusto- conical confuser. Surprisingly, it has been found that this inexpensive design provides considerably faster and more intimate mixing than is achieved with conventional static mixers. Moreover, it has also been discovered that when fluids are passed at a sufficient rate through a device fitted with a heat transfer means, such as a thermostatting jacket, surprisingly more effective (i.e., greater or faster) transfer of heat to or from the fluid and significantly better maintenance of temperature uni¬ formity can be achieved than with conventional static or even nonstatic mixers. The device is suitable for use with any fluid; that is, any fluent material, including liquids, gases and particulates.

Thus, the new design significantly improves the intensity of mixing over that achieved by conventional methods. Such improved mixing is especially advantageous when high speed intimate mixing is required. However, the extremely intense mixing made possible by the new design is also valuable in heat transfer applications, especially when high speed heat transfer and/or mainte- nance of isothermal conditions is desired, or when car¬ rying out chemical reactions in which intense mixing is

desirable, especially many polymerization reactions. In fact, the new design has been found to be surprisingly effective in a wide range of reactions in increasing reaction rates and yields over those achieved with con- ventional designs.

The device, therefore, is also ideally suited to many chemical reactions in which not only mixing but also heat transfer and/or maintenance of a uniform temperature throughout the reaction mixture is essential. As a re- suit, a degree of control never previously possible can be asserted over many reactions by implementation of the device and method of this invention. For example, chlor- ination of about half of the double bonds in synthetic rubber (cis-1,4,polyisoprene) is commonly achieved in industrial practice. In conventional processes, some of the chain molecules are nearly fully chlorinated and some have essentially no chlorine content. The distribution of chlorinated and non-chlorinated molecules is. not de- sirable but is impossible to eliminate or control by means of conventional techniques. However, when chlori- nation is carried out in the device of the present inven¬ tion, essentially all the molecules in the product are about 50% chlorinated, resulting in a more uniform mater¬ ial with superior properties. The unfavorable results caused by the much higher rate of reaction compared to rate of mixing in standard batch reactions therefore are avoided. The improved mixing and temperature uniformity are particularly suitable to polymerization reaction such as hyperfast, low temperature polymerization, wherein the new design has been found to permit production of polymer within a desired narrow ζ range of molecular weight.

Thus, some examples of synthesis products and processes to which the present device is suited are ethyl chloride, ethylene dichloride, polyisobutylene, high olefin oligomerization, polyisoprene, styrene-butadiene rubber (SBR), butyl rubber and piperylene oligomers.

Other products or processes to which the present device may be applied include alkylation of hydrocarbon streams, emulsion polymerization, chlorination reactions, polymer ozonation, neutralizations and processes in which extrac- tion, dispersion and mixing are critical issues. Such products and processes are identified as illustrative of the wide variety of processes to which the present device and techniques may be applied and should not be viewed as a limitation of its applicability. Moreover, the device that has been found to be capable of providing such numerous benefits is of a design that is inexpensive to manufacture. It involves simply lengths of pipe and conical sections such as re¬ ducers. And, because the device is static, it is charac- terized by the several advantages of low capital costs, low maintenance and low energy consumption. In fact maintenance and shut down times and frequency may be even lower than with conventional static mixers that employ very small passageways such as orifices. The smallest diameter through which the fluid to be treated is routed typically is still much larger than such orifices, making clogging unlikely. The present design also reduces the significant backflow pressures associated with forcing a fluid through a small orifice. Yet, even without such extremely restricted passageways, the device of this invention does not suffer from the conventional drawback of static mixers; namely, a difficulty achieving an in¬ tensity of mixing comparable to that achieved by mixers with mechanical agitators. To the contrary, the degree and rate of mixing achieved with the new design has been found to be capable of exceeding what is achieved by typical mixers employing mechanical agitation means. In addition, because of the superior efficiency of the new design, a substantially smaller device of this invention can be used in place of larger prior art devices, thereby cutting costs, including capital costs and other costs

related to size and space requirements even further. Also, because a device smaller than conventional reactors may be used, smaller hold-up volumes of reaction mixture are present and so in many cases the method of this in- vention is safer than prior art techniques. Moreover, the superior heat transfer possible with the device re¬ sults in energy savings over conventional heat exchang¬ ers.

Thus, the present method permits many chemical reactions to be carried out more efficiently. The higher conversion rates result in lower raw material usage, reduced catalyst consumption, reduced by-product forma¬ tion and reduced waste. The product, therefore, is of higher quality than those synthesized by conventional techniques. The reduced material consumption, improved product quality and reduced by-product and waste forma¬ tion, therefore, render this new device and method en¬ vironmentally advantageous as well.

Referring now more particularly to the drawings and Figure 1, it will be seen that the device of this invention comprises a series of chambers C lf C 2 , C 3 and C 4 through which a fluid to be treated flows under pressure in the direction indicated by arrow F. Although four chambers are shown in Fig. 1 for illustrative purposes, it is required only that the number of chambers be at least two. Thus, the series of chambers may be viewed as comprising at least one pair of adjacent chambers, with the series of Fig. 1 comprising three pairs of adjacent chambers; namely, Ci and C 2 , C 2 and C 3 , and C 3 and C 4 . In the interest of costs, it is preferred that the lowest number of chambers that stills provides the de¬ sired mixing and/or heat exchange without unduly high flow rates be used. Thus, under most conditions the practical number of chambers would not exceed about twelve (i.e., eleven pairs) and more typically, it would not exceed about nine (i.e., eight pairs). Many applica-

tions would involve two to about five chambers. General¬ ly, the higher the viscosity of the fluid being treated, the higher the number of chambers and the higher the linear flow rates of the fluid being treated. The chambers will be described by reference to the first chamber in the series, chamber C^ The other cham¬ bers in the series are of equivalent shape and preferably proportional to chamber C x . Most preferably, all chambers are of identical dimensions to the first. Each chamber is defined by an inlet section (shown in Fig. 1 as frus¬ to-conical diffuser 1) and an outlet section (shown in Fig. 1 as frusto-conical confuser 3), which have inlets li and 3i, respectively, and outlets lo and 3o, respec¬ tively. As used herein, the term "frusto-conical" refers to a portion of a cone with the top portion near and including the vertex cut off by a plane parallel to the base; in other words, the surface of a frustum, excluding the ends. The diffusers (and confusers) angle outwardly (or inwardly) at an angle α as measured from a line par- allel to the axis along which the chambers are arranged serially and about which device is symmetric. In other words, angle o is a measure of the slope of the internal surface of the diffuser or confuser with respect to the axis. Preferably, the angle α is the same for each dif- fuser and confuser section. Therefore, the shape of the diffuser or inlet section and the shape of the confuser or outlet section are such as to progressively decreases or increases, respectively, the pressure and velocity of the fluid flowing therethrough. The frusto-conical shape of each diffuser and confuser causes respective decreases and increases in pressure and velocity to be exponential; that is, generally proportional to tan a times the square of the distance along the central axis of the diffuser or confuser. The outlet lo of the diffuser 1 and the inlet 3i of the confuser 3 are affixed to respective opposite ends

of a cylindrical conduit 2 extending therebetween. The conduit 2 is of constant cross-sectional area, preferably circular of diameter D, and has a length L. All refer¬ ences herein to diameters are to inside or internal diam- eters. The diffuser 1 has a relatively small or reduced cross-sectional area, preferably circular of diameter d, at its inlet and diverges to a relatively large cross- sectional area, preferably circular of diameter approxi¬ mately if not exactly equal to that of the conduit 2 at its outlet lo. Thus, the cross-section and the internal diameter of the diffuser increases along its axis from its inlet to its outlet. Accordingly, conduits 2 are of circular cross-section as viewed in the direction of arrow F. The axis along which the chambers are aligned, therefore, is defined by the centers of the circular cross-sections.

The confuser 3 is of dimensions preferably iden¬ tical to those of diffuser 1, but is of reverse orien¬ tation. Thus, confuser 3 has a relatively large cross- section (diameter) approximately equal to that of the conduit 2 at its inlet 3i and converges to a relatively small or reduced cross-section (diameter d) at its outlet 3o. That is, the cross-section (internal diameter) of the confuser decreases along its axis from its inlet to its outlet. The inlet li of the first chamber in the series, chamber C x of the diffuser 1, may be defined as the entry port of the device wherein materials to be treated may be injected into the device, while the outlet of the confuser of the last chamber in the series, cham- ber C 4 in the case of Fig. 1, can be defined as the exit port of the device where the treated materials emerge from the device. The chambers C in the series are juxta¬ posed to abut each other without additional piping there¬ between. Thus, the outlet of the confuser and the inlet of the diffuser between adjacent chambers are contiguous or affixed together and the outlet of the confuser of

each chamber but the last one in the series may be con¬ sidered the inlet of the diffuser of the next chamber in the series. For example, the outlet 3o of the confuser 3 of chamber Ci is the inlet li' of the diffuser 1' of C 2 . Optionally, the series of chambers may be sur¬ rounded by a jacket or shell 6. In such configuration, the device may be employed as a heat exchanger. The shell 6 is of conventional design and any standard heat transfer fluid, such as water, may be employed within the shell. Under ordinary heat transfer conditions, the heat transfer fluid would be directed to flow into port 7 and out of port 9 for concurrent flow as shown in Fig. 1 or, less preferably, into port 8 and out of port 7 for coun¬ ter-current flow, as desired. Surprisingly, significantly superior results have been found to be achieved for relatively narrow ranges of relative dimensions and ratios for D, d, L and angle α, and the efficacy of mixing falls, off sharply upon devia- tion from these ranges and ratios. Although the wide range of types of operations to which the present device and method are applicable make it impossible to provide generalized formulae for determining the precise combina¬ tion of optimum dimensions for each case, the ranges of optimum relative dimensions are as follows. The ratio of D to d should be from about 2 to about 5 (or stated dif¬ ferently, d:D should be from about 0.2 to about 0.5), α should be from about 15° to about 60°, 30° to about 60° in most cases and from about 15° to about 30° in certain specialized cases in which the viscosities or densities of two liquid reactants differ greatly such as by about 5:1, and L should be from about equal to d to about 5D, preferably to about 4D, although typically L would be approximately equal to D times angle α as measured in degrees, divided by.15°. The number of chambers has been discussed above.

As noted, the device of this invention can be adapted for several different types of operations, in¬ cluding but not limited to pure mixing, emulsion forma¬ tion, heat transfer and many different types of chemical reactions, especially rapid chemical reactions such as "fast" reactions (those in which the reaction is at least 50% complete in one minute or less). Because each opera¬ tion, and each reaction, involves distinct parameters and distinct types of processes, each requires a distinct reactor design. Thus, the optimum dimensions and ratios depend on the particular mixing, heat transfer or reac¬ tion operation being carried out. For example, the op¬ timum range of angle α for production of synthetic rubber has been found to be from about 45° to about 60°, for polymerization of isobutylene is from about 43° to about 47°, and for production of alkyl gasoline to be from about 15° to about 19°. As a rule of thumb, which might not apply in a particular situation, when two liquid reactants are treated (and either or both of the reac- tants may be a combination of liquids), if the proportion of the viscosity of the more viscous liquid to the other is about 5:1, the optimum value for angle α is from about 16° to about 18°, if the proportion is about 4.5:1, the optimum value for angle α is from about 16° to about 20°, if the proportion is about 2:1, the optimum value for angle α is from about 17° to about 45° and preferably about 30° to about 45°, and generally if the liquids are of about equal viscosity (i.e., about 1:1 to about 4:1, especially about 1:1 to about 2:1), the optimum value for angle is from about 30° to about 60°.

Generally, the optimal design might depend on such factors as the half conversion time of the raw materials, the kinetics involved, the characteristics of the major reactants and diluents therefor such as their ratios, flow rates, phase conditions, densities and viscosities, the changes in densities and viscosities during the pro-

cess (whether in mixing, reacting or both)*, operating pressure, side reactions (if any) and their kinetics, heat of reaction, vapor pressure curves, temperature limits, temperature dependencies of kinetic parameters for the main and side reactions, and phase conditions. The range of optimum dimensions also depends on the spacial orientation of the device. In operation, the device may be oriented horizontally, in which the axis along which the chambers extend serially is horizontal, or vertically, in which that axis is vertical. In the vertical orientation flow upwardly against gravity is preferred. Orientation at angles other than horizontal or vertical is undesirable and has been found to lead to pockets where portions of the fluid being treated stag- nate. Generally, it has been found that horizontal orientation results in narrower optimum ranges of rela¬ tive dimensions than does vertical orientation. Thus, in many applications, vertical orientation is preferred, with flow against gravity. Typically, the actual overall dimensions depend at least in part on the desired flow rate. Generally, the sizing of the device is based on the linear flow rate through the narrowest passages, those having the diameter d. The device must be small enough to result in a suf- ficiently high linear flow rate through the narrow pas¬ sages of diameter d to achieve sufficiently turbulent flow. In cases in which the pressure on the reaction mixture is important, the resulting pressure on the mix¬ ture is, of course, a significant consideration. The flow rate should be such as to produce the appropriate pressure. Aside from that consideration, the maximum flow rate is limited by the increased force necessary to pump the materials through the device at the increased rate. Thus, there is no true upper limit to the flow rate. It is guided by the desired pumping force, degree of mixing and production rate. Generally, a point may be

reached at which the amount of extra force- required to increase the flow rate a certain amount, and the extra costs attendant thereto, are not sufficiently rewarded by the resulting increase in mixing or flow rate. Typical- ly, at some point the pumping force necessary for each incremental increase in flow rate goes up exponentially while the increased degree of mixing and flow rate ach¬ ieved by such incremental increase in pumping force levels off. The minimum flow rates necessary to induce suf¬ ficient turbulence are dependent upon the characteristics of the fluids themselves, including such variables as the viscosity and the friction factor of the fluids. How¬ ever, it has been found that for many fluids of interest, such as those set forth in the organic systems of the working examples below, a linear flow rate through the small diameter d of at least about 0.5 meters per second (a volumetric flow rate of at least about 0.9 cubic meters per hour for a diameter d of 25mm), preferably at least about 1.4 meters per second (a volumetric flow rate of at least about 2.5 cubic meters per hour for a dia¬ meter d of 25 mm) has been sufficient. Although the turbulence is dependent on the linear flow rate as op¬ posed to volumetric flow rate, the volumetric flow rate is given for an illustration of the surprisingly large volumetric treatment capacity for even relatively small reactor. For example, in the case of water in the exam¬ ples below, a volumetric flow rate of 0.7 cubic meters per hour when d=20mm, corresponding to a linear flow rate of about 0.6 meters per second through the narrow pas¬ sages, was found to be sufficient to achieve highly ef¬ fective heat transfer.

Superior results for organic materials have been found without undue force being required for pumping the material therethrough for linear flow rates at least about two, especially at least about six, meters per

second (a volumetric flow rate of about 3 * 67, especially about 11, cubic meters per hour for a diameter d of 25 mm) . However, the improvement in molecular weight and molecular weight distribution with each increase in flow was not as pronounced at higher rates. The other dimen¬ sions of the reactor are dependent upon the diameter d according to the ratios and ranges set forth above. Thus, with a reactor of internal diameter of only about 1" at the diameter d and 2"-5" at diameter D, material at a volumetric flow rate of 2.5 cubic meters per hour to 11 cubic meters per hour or more may be treated. Production rates in other situations will depend upon the materials being treated and the treatment being carried out.

Accordingly, the method of this invention may be carried out as follows. A fluid, which may be a combina¬ tion of fluent materials, is pumped into the entry point of the device at a pressure sufficient to achieve the desired flow rate through the mixer. The fluid may be of a single component, for example, in cases in which a purely heat exchanging operation is carried out. More typically, however, the fluid would be a combination of components, such as two liquid reactants, a liquid and particulate matter (e.g., finely divided solids) or a gas and liquid in such cases as for aerating the liquid. In the case in which heat exchange is desired, the mixer is surrounded by a heat transfer means such as discussed above. The mixer is designed for continuous flow proces¬ ses and as such, may be installed directly in a con¬ tinuous process system. The present inventors, therefore, have discovered a particular design that is capable of achieving mixing at an intensity and efficiency unmatched by the myriad of designs currently employed. While not wishing to be bound by any particular theory, the inventors believe that the particular configuration of the present device achieves such intensity and efficiency by operating on

the fluid in the following manner. Passing the fluid through the diffuser initiates a turbulent vortex. The central conduit allows the vortex to reach maximum inten¬ sity before the fluid reaches the confuser. Thus, the length of the conduit should be long enough to allow a full swirl of fluid to develop, but not so long to allow dampening of the turbulent vortex before reaching the confuser. The chambers should be connected to avoid dampening the turbulence before a new vortex is developed in the next chamber. Thus, it is highly preferred that the chambers be contiguous, that is, that they abut each other. Turbulence dampens quickly as the chambers are spaced apart. Thus, while a spacing of, say, up to one- tenth of the length of the central section or conduit may result in significant dampening that can be tolerated in some cases, a spacing on the order of one-half or more of the length of the central section may result in substan¬ tial and highly undesirable dampening.

The importance and distinctiveness of this design can be seen in the fact that deviations from the design in shape or dimensions results in dramatic diminution of effectiveness. Thus, if portions of the chambers are curved with respect to the axis extending therethrough (that is, if a plane in which the axis lies intersects a chamber wall in a curve instead of a straight line seg¬ ment) such as if the diffusers or confusers are bell- shaped, or the chambers are spaced apart such as by cy¬ lindrical conduits linking the confuser of one chamber to the diffuser of the next, or if the cylindrical conduit 2 were so long as to permit a diminution of turbulence before the fluid reaches the confuser or so short as to interrupt the full swirl of turbulence, the degree of mixing decreases drastically.

The following examples describe preferred embodi- ments of the invention. Other embodiments within the scope of the claims herein will be apparent to one skill-

ed in the art from consideration of the specification or practice of the invention as disclosed herein. It is intended that the specification, together with the exam¬ ples, be considered exemplary only, with the scope and spirit of the invention being indicated by the claims which follow the examples. In the examples all percen¬ tages are given on a weight basis unless otherwise in¬ dicated.

EXAMPLE 1 Five-chamber thermostatic-jacketed, horizontally oriented devices of the design of this invention with relative dimensions within and outside the optimum ranges were studied for heat transfer effectiveness. The dia¬ meter d of each device was 2 cm. Water was passed through the device at a rate of 0.7 meters per second. In order to measure the heat transfer, each device was equipped with a differential thermocouple, digital mil- livoltmeter and rotameter to measure the rate of flow into the first chamber and the temperature difference of the liquid being treated between a point immediately before the liquid enters the device and a point at which the liquid exits the device. The heat removal achieved was recorded as the temperature loss per volume of liquid treated. The results obtained are set forth in the table below, with the first seven trials representing relative dimensions within the optimum ranges, α being given in degrees and SHR being the specific heat removal in °C per square centimeter of surface area of the device.

Four-chamber devices of the design of this inven¬ tion with relative dimensions within and outside the optimum ranges were studied for effectiveness in emul- sification. Water and colored carbon tetrachloride were pumped through the devices at rates sufficient to ensure turbulent flow (not less than 2.5 m 3 /hr) to form emulsions in which carbon tetrachloride droplets were dispersed through a continuous water phase. The quality of the resulting emulsions was analyzed by photographic and microscopic methods. A higher quality emulsion is in¬ dicated by a lower mean diameter of the carbon tetrachloride particles and a higher portion of the par¬ ticles close to the mean. Trial numbers 1 through 12 were conducted at a flow rate of 130 liters per minute (7.8 m 3 /hr) . In all trials (1-13), the device was ar¬ ranged vertically and the flow was against gravity. Trial number 11 was conducted with one of the components injected into the inlet flow stream at an angle of about 45° from the axis of the device to intersect the flow of the other component (which was injected axially into the device) before entry into the first chamber. Trial num¬ ber 12 was conducted with one of the components injected at an angle of 90° from the axial flow of the other com- ponent (i.e., the flow of one component was vertically

upward and the other horizontal) and the flows again intersected before entry into the first chamber. Trial number 13 was conducted at a reduced flow rate of 70 liters per minute (4.2 m 3 /hr) . The results are set forth in the following table, in which α is in degrees, μ represents the mean carbon tetrachloride particle dia¬ meter in microns and "Concentration" is the numerical percentage of particles within twelve percent of the mean diameter. The first four trials representing relative dimensions within the optimum ranges.

*Comparative tests not within optimum ranges.

These results indicate that an L:d ratio below the optimum range leads to a rapid deterioration in emulsion quality in terms of the degree of dispersion. It is believed that this deterioration is due to deformation of the turbulent vortex when contacting the wall of the confuser section. Although an L:d ratio above the op¬ timum range does not appear in these trials to have led to a significant drop in emulsion quality, it is undesir¬ able because it leads to an increase in the dimensions of the device.

These results also indicate that varying the direction of flow (i.e., the angle of orientation of the device) from upward influenced the particle size only slightly, but the degree of dispersion worsened sharply and dynamic stagnation zones formed near the border bet-

ween the diffusers and the cylinder sections, where rela¬ tively large particles resided too long. Decrease of flow rates were found to lead to larger particles.

EXAMPLE 3 The influence of density on the optimum angle α for mixing was studied by pumping 50:50 volume water/organic mixtures at 2 liters per second through nine-chamber devices of various angles α in which D was 50mm, d was 25mm and L was 100mm and measuring the drop- let size of the resulting dispersed organic phase. The following results were obtained for each water/organic mixture.

Numerical % of Drops Having a Diameter Less Than 1mm α ° Water/Hexane Water/Dichloroethane Water/CC1 47 43

95 75

95 78

80 95 60 84 For reference, the density of hexane is 0.66 gm/cm 3 , of dichloroethane is about 1.2 gm/cm 3 , and of carbon tetrachloride is about 1.6 gm/cm 3 . The viscosities of these organics increases with density (0.33 cp, 0.80 cp and 0.97 cp, respectively), but in this situation, it is believed that the densities and not the viscosities in¬ fluenced the optimum angle. These data indicate that in the case of a low density of one of the components (hexane), the optimum angle was in the range of about 17° to about 30°, and that as the density increased, did the optimum value of the angle α, to 17°-45° for dichlor¬ oethane and 45°-60° for carbon tetrachloride.

EXAMPLE 4 The effect of varying angle α on isobutylene oligomerization was studied with five chamber devices in which D was 52mm, d was 25mm and L was 104mm. The reac¬ tion was carried out a -5°C (with no thermostatting jack¬ et) , and an isobutylene concentration of 20% by weight in

the presence of 4.5 X 10" 3 mole/liter AlCl 3 in C 2 H 5 C1. High molecular weight, indicating greater reaction pro¬ gress, and a narrow range of molecular weights, indicat¬ ing thorough mixing and temperature homogeneity, were desired. The results for a flow rate of 2.7 m 3 /hr. are shown in the following table, in which α is in degrees, MW refers to molecular weight and MWD is the molecular weight distribution in terms of the percent range about the mean molecular weight in which the molecular weights falls.

Further tests were conducted with the device of trial 5 of this example; that is-, the device in which the angle α is 45°. The tests were conducted with the same reactants as the earlier trials of this example, but at various flow rates. The following results were obtained, wherein the flow rates, Q, are given in m 3 /hr.

A device of the design of the present invention was tested against a standard bulk reactor (a continuous¬ ly stirred tank reactor) in isoprene polymerization. The device comprised five chambers, the linear flow rate through the narrow diameters d was 2.5 meters per second, D was 100mm, d was 50mm, angle o was 45° and L was 300mm. The device was not fitted with a thermostatting jacket.

Conventional isoprene polymerization technique were em¬ ployed with the standard bulk reactor. The following comparative results were obtained.

Standard Bulk Device of Present Reactor Invention

Percentage of cis-l,4-links 97 to 98 98.0 to 98.7 Density (kg/m 3 ) 910 to 920 910 to 920

Percentage of metal impurities in the rubber product*: iron 0.001 to 0.002 trace titanium 0.04 to 0.05 0.001 to

0.002 Loss of mass at 105°C (%) 0.40 to 0.45 0.20 to

0.25 Catalyst consumption (relative) 1 0.4

♦Lower metal impurity is associated with an increase in resistance to heat.

In view of the above, it will be seen that the several advantages of the invention are achieved and other advantageous results attained.

As various changes could be made in the above methods and compositions without departing from the scope of the invention, it is intended that all matter contain¬ ed in the above description and shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.