Technical Field

The present invention relates to processes and devices for phase separation of materials, particularly for use in multiple, simultaneous synthesis, purifica¬ tion and isolation of compounds.

Background Art

Various apparatus and methods are known for the multiple, simultaneous synthesis of compounds, including, but not limited to, organic compounds. Some of the preferred methods and apparatus are shown, for example, in U.S. Patent No. 5,324,483 entitled "Appara¬ tus for Multiple Simultaneous Synthesis." In accordance with that patent, a plurality of compounds are simulta¬ neously synthesized in an array format which is compati¬ ble with standard techniques of organic synthesis. The sample handling is carried out using automated systems for speed, accuracy and precision.

The method and apparatus disclosed in the '483 patent can be used for products generated from either solid (resin) support or solution based synthesis techniques . The primary steps necessary to perform the synthesis are the development of a synthetic route that will be feasible with the solid or solution techniques utilized, the verification of the synthesis using representative examples, and the execution of the

multiple, simultaneous synthesis within an array format to generate the plurality of compounds.

The '483 patent increases the flexibility and diversity of structures that can be produced by paral- lei, solid phase or solution-based chemical synthesis. Where solution-based chemistry is involved, conventional two-phase liquid/liquid extraction protocols are uti¬ lized. These techniques are not as easily amenable to automation as techniques using solid or resin-support techniques. Furthermore, products generated by solid- based chemistry often require post-synthesis liquid/liquid extraction protocols analogous to solu¬ tion-based chemistry.

Summary Of The Invention

It is an object of the present invention to provide improved devices, methods, and systems for liquid phase separation. It is also an object of the present invention to provide phase separation devices, methods, and systems which are useful for multiple, simultaneous synthesis, purification and isolation.

It is a further object of the present inven¬ tion to provide two-phase separation devices, methods, and systems which are more amenable to automation and thus which will facilitate more efficient and faster simultaneous, multiple synthesis, purification and isolation of compounds. It is a still further object of the present invention to provide phase separation devices which are less expensive and easier to manufac¬ ture than known separation devices and which also can be provided in disposable form.

It is another object of the present invention to provide a device that detects an interface between two liquids by a physical means, without the need for volume control or liquid level detection. It is still another object of the present invention to provide a device which can separate emulsions. It is an addi¬ tional object of the present invention to provide a device which can be used for multiple extractions with one or more solvents in aqueous phase.

It is a still additional object of the present invention to provide a liquid phase separation system which provides drainage by gravity without the need for pressure or vacuum. It is also an object of the present invention to provide agitation and improved extraction efficiencies with controlled or automated dispensing of liquids .

It is still another object of the present invention to provide phase separation devices for high- throughput synthesis, workup isolation and purification and which can be utilized for heavier-than-water and/or for lighter-than-water applications.

These and other objects are met by the present invention which provides improved devices, methods, and systems for liquid phase separation of different materi- als. In accordance with one embodiment of the present invention, a hydrophobic filter disk is retained on top of or between porous filter devices or frits in the lower end of a phase separation cartridge. The filter disk may be constructed from a variety of hydrophobic materials, including phase separator paper (IPS) or Teflon. The cartridge has an open end in which the

solution or slurry of materials is introduced, often with a solvent, and a lower end which has an outlet for draining and collection of the separated non-hydrophobic materials. The cartridge may also be constructed from a variety of different materials, such as polypropylene. Preferably, the separated material is also passed through a drying device attached to or positioned immediately adjacent the exit of the cartridge.

When used for reaction workup and quenching, the crude reaction mixture is introduced into the separation cartridge containing an aqueous reaction quenching or workup solution, such as water or saturated ammonium chloride. The hydrophobic nature of the filter disk prevents the quench reagents from passing before the reaction mixture is introduced. The extracted materials in the higher density organic solvent are separated by passing through the frits and hydrophobic filter disk while the aqueous layer is retained above the filter disk. The separated materials can then be dried by passing them through a drying device or car¬ tridge.

For lower density solvents or materials (a/k/a "lighter than water" materials) , another embodiment of the invention utilizes an hydrophobic "thimble" or elongated cup-shaped filter member inside the cartridge. The thimble filter cup can be constructed from any conventional hydrophobic materials. The liquid materi¬ als (water, solvent and soluble component to be separat¬ ed) are introduced individually or as a mixture into the thimble-shaped filter in the cartridge and the lower density (lighter-than-water) materials are separated by passing through the sides of the filter member and out

through the lower end of the separation cartridge. The thimble filter cup can be fluted or provided with raised ridges in order to center and space it from the walls of the cartridge. Alternately (or concurrently) , the inner surface of the cartridge can be provided with raised projections or a centering ring for the same purposes. Also, the separation cartridge and filter cup can have any cross-sectional configuration, such as circular, oral, square, etc. A flat frit or perforated support can be provided at the base of the cartridge to help support the thimble filter cup.

Preferably, the porosity and construction of the filter disk or thimble filter cup enable the organic liquids and materials to drain rapidly by gravity. With the invention, the application of pressure or vacuum are not necessary.

These and other features and benefits of the present invention will become apparent when the follow¬ ing description is viewed in accordance with the at- tached drawings and appended claims.

Brief Description Of The Drawings

FIGURE 1 is an exploded view showing the phase separation cartridge and drying device;

FIGURE 2 is an exploded view of the unique filter device;

FIGURE 3 is a plane view showing the separa¬ tion cartridge or container and the drying device or cartridge assembled together;

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FIGURE 4 is a cross-sectional view of the invention shown in Figure 3, the cross-sectional view being taken along lines 4-4 of Figure 3 and in the direction of the arrows;

FIGURE 5 illustrates an alternate embodiment of the invention useful for lighter-than-water applica¬ tions;

FIGURE 6 is a cross-section of the device shown in Figure 5 with the cross-section taken along line 6-6 in Figure 5 and in the direction of the arrows;

FIGURES 7A, 7B, 7C and 7D illustrate alternate embodiments of thimble or cup-shaped filter devices;

FIGURE 8 illustrates still another embodiment of the invention;

FIGURES 9 and 10 are cross-sectional views of the device shown in Figure 8 with the cross-sections taken along lines 9-9 and 10-10, respectively, in Figure 8 and in the direction of the arrows;

FIGURE 11 illustrates an alternate interior configuration for the cartridge;

FIGURES 12 and 13 illustrate still further alternate interior configurations for the cartridge;

FIGURE 14 is a cross-sectional view of the device shown in Figure 13 with the cross-section being taken along line 14-14 in Figure 13 and in the direction of the arrows; and

FIGURES 15A, 15B and 15C illustrate represen¬ tative additional cross-sectional sizes and shapes for the separation cartridge and thimble filter cup in accordance with the present invention.

Best Mode(s) For Carrying Out The Invention

The apparatus or device used with the present invention for heavier-than-water applications is shown in Figures 1-4 and indicated generally by the reference number 10. The device 10 includes a separation car¬ tridge 12 and a drying device 14. The extraction cartridge 12 is an elongated thin walled container, preferably made from glass or a plastic material. If the separation cartridge 12 is going to be reused, then preferably it is made from glass or a plastic material such as polypropylene which can be adequately cleaned, sterilized and reused. If the separation cartridge 12 is disposable, then preferably, it is made from a plastic material such as polyethylene or polypropylene.

The separation cartridge may have a ledge or lip 16 at its open end to facilitate manual handling and/or automation. The cartridge 12 has a funnel or cone-shaped structure 18 at its opposite end which terminates in a material discharge orifice or outlet 20. The outlet 20 can have any desired shape, but preferably has a tapered shape as shown in Figure 1 in order to mate with a drying device or cartridge 14 (as explained below) .

The phase separation mechanism is shown in more detail in Figure 2 and designated by the reference numeral 30. The phase separation mechanism or apparatus

includes a thin circular wafer-like hydrophobic paper disk 32 placed on top of or sandwiched between a pair of thin wafer-like frit members 34 and 36. Preferably, the frit members 34 and 36 are polypropylene frits, but the frit members can be made of any other conventional filtering material, such as Teflon or glass.

The filter disk member 32 can be made from any conventional hydrophobic materials, but preferably is a silicone treated paper product, such as the phase separator product from Whatman International, Ltd., Maidstone, England. The disk member 32 can also be made, for example, from a conventional phase separator paper (IPS) or Teflon.

Alternatively, another layer, such as a mesh or screen member could be used for reinforcement, if desired. Such a fourth disk member is shown in dotted lines in Figure 2 and indicated by the reference numeral 38. If desired, as an embodiment, one or more thin wafer-like mesh or screen members could be used in place of the frits 34 and 36.

In use, preferably three layers 32, 34, and 36 are provided and positioned closely together to form a sandwich or laminated type structure. The diameter DI of the filter device 30 is the same as the inside diameter D2 of the extraction cartridge 12. In this regard, it is preferable that the filter device 30 be sized to contact the inside walls of the extraction cartridge in order to prevent leakage of materials around the device and through the outlet 20.

If only two members are utilized, i.e. one filter disk member 32 and one frit member, then it is preferred that the frit member be positioned below the filter disk member (i.e. on the downstream sides of the filter disk member) . Also, it is possible to utilize two or more laminated phase separation mechanisms 30 in the extraction cartridge 12 to insure better separation, although this might slow down the speed of the separa¬ tion process.

The drying device or cartridge 14 is also preferably made from a plastic or glass material. The drying device 14 includes a hollow cylindrical body 40, an inlet 42 and an outlet 44. Devices of this type are commercially available. Alternatively, a conventional chemical drying material, such as sodium sulfate (NaS0 ₄ ) , which removes residual water from hydrophobic solvents and reagents, may be placed in the body 40. Some conventional drying cartridges use a paper drying member, such as member 50 shown in Figure 4.

The inlet 42 of the drying device is adapted to mate with the outlet 20 of the separation cartridge 12. The outlet 44 of the drying device 14 allows the separated material to flow into a collector vessel of some type, such as a beaker or test-tube (not shown) after the separated material is dried by the drying member 50.

If desired, the final separated product could be further purified by conventional means, such as chromatography.

The present invention is an alternative to two-phase liquid/liquid quench and extraction protocols. Solutions of this type from which liquid/liquid extrac¬ tion protocols include, for example, oil or oil-based materials and water.

The present invention can be utilized for virtually any heavier-than-water extractions, such as dichloromethane (or CH ₂ C1 ₂ ) (a/k/a methylene chloride and DCM) . DCM is a solvent commonly used in organic synthe- sis reactions. An alternative use of the present invention is for the extraction of byproducts from aqueous soluble salts by repeated introduction (and draining) of hydrophobic solvents to the aqueous materi¬ als retained in the cartridge. The salts can later be liberated by neutralization and extracted with hydro- phibic solvents as described earlier.

The present invention is amenable to automa¬ tion. This is due to its structure, simplicity, and ease of operation. It is particularly useful for compound workup and separation techniques. For example, for an automated reaction workup, a material, such as a reaction mixture in solution with THF (tetrahydrofuran) , can be quenched with, for example, saturated ammonium chloride (sat. NH ₄ C1) , diluted with DCM and extracted. The DCM layer containing the desired product is allowed to separate through the filter device 30 in the separa¬ tion cartridge 12. The drying device 14 extracts any residual water which may be in the organic solution.

Initially, the reaction mixture is placed in solution with, for example, tetrohydrofuran (THF) and the mixture is then introduced into the separation

cartridge 12 already containing the saturated ammonium chloride or other quenching material.

An example was carried out utilizing a proto¬ type of the present invention in order to show its usefulness and attributes . The example also demon¬ strates the ability of the invention to be used for parallel processing. In this regard, the phase separa¬ tion device was used to synthesize and purify imines generated from Grignard reactions.

In this example, a material of 5-nitroanthra- nilonitrile was dissolved in 1.0 ml of tetrahydrofuran

(THF) . The two materials were placed in a 10 ml vial.

A stir bar and argon blanket were applied. Then, 0.4 ml of 3.0 molar of phenylmagnesium bromide in THF was added to the mixture in the vial . The color change was noted from red to brown to black. An additional 1 ml of THF was added to facilitate stirring.

The reaction was monitored by thin layer chromatography (TLC) . After 30 minutes, one-half of the reaction mixture was transferred to a separation car¬ tridge 12 assembled with a drying device 14 in accor¬ dance with the present invention. The reaction was quenched when added to an aqueous solution of saturated ammonium chloride (NH ₄ C1) already residing in the phase separation cartridge. DCM was introduced to this mixture to extract the desired product. The phase separation mechanism 30 included two polypropylene frit members 34 and 36, and one silicon treated paper filter disk member 32.

The imine was dissolved in DCM and was sepa¬ rated from the material in the extraction cartridge and passed into and through the drying device through outlet 20. The material was collected in a conventional container.

Cartridge and filter devices for use with lighter-than-water applications as well as heavier-than- water applications are shown in Figures 5-15. One preferred embodiment is depicted in Figures 5 and 6 and indicated by the reference number 60.

The device 60 has a separation cartridge 62 which is similar in size, shape and material to car¬ tridge 12 described above with reference to Figures 1-4. The cartridge 62 has a ledge 66 at its open end and a funnel or cone-shaped structure 68 at the opposite end terminating in a discharge orifice 70.

The phase separation mechanism comprises a cup or thimble-shaped filter device 64 which is positioned inside the cartridge 62. The thin-walled thimble 64 is made of a hydrophobic paper material, and preferably is made of the same material described above with reference to filter disk member 32.

A perforated support member 72 is positioned near the bottom of the cartridge 62 in order to support the thimble filter device 64 therein and also prevent the device 64 from wedging or sealing against the interior walls of the cartridge. The support member 72 can be any perforated member, such as a mesh or screen member, or another filter member which would allow the

separated materials to pass through it, such as a polypropylene frit .

In the embodiment shown in Figures 5 and 6, the thimble filter member 64 has a plurality of flutes or ridges 74 around its outside circumference. The flutes 74 allow the outside of the thimble to be spaced in most places from the inside wall of the cartridge and thus allow the separated materials to flow more easier and quickly down the cartridge toward the outlet 70. The flutes avoid surface tension and/or capillary action being created between the walls of the cartridge and the outer surface of the thimble .

The flutes on the thimble also provide a greater surface area for materials to pass through the walls. The flutes further aid in accurately centering the thimble in the cartridge which is necessary for manual or automatic dispensing of liquids into the device 60. This will assure reproducible and accurate liquid transfer into the thimble.

Preferably, the cartridge should have a capacity or volume of 12 milliliters, or approximately 1.0 ml, for a 96-well plate format. The porosity of the frit/support member 72 should be about 100 micron. The porosity of the filter paper for the thimble should be known and the inside dimensions of the thimble should accommodate approximately 10 ml of liquid. The length (height) of the thimble should be approximately the same as, or just below the height of, the cartridge (or 96- well plate) .

In use, a drying device may also be used with the device 60. The preferred drying device is described above with reference to Figures 1-4 and identified by the reference number 14.

Alternate shapes and types of thimble filter members are shown in Figures 7A, 7B, 7C and 7D. All of these are adapted to fit with a container device, such as cartridge 62. Thimble member 80 (Figure 7A) is a plain, smooth-walled, cup-shaped device, while thimble member 82 (Figure 7B) has four wedge-shaped or angled ridges 83 positioned around its outside surface. The ridges 83 are similar to the flutes 74 described above and fulfill the same purposes.

In Figure 7C, the thimble member 84 has a plurality of angled or spiral-shaped flutes or ridges 85 around the outer surface. The spiral flutes 85 are for the same purposes as the flutes 74 and ridges 83 de¬ scribed above. Finally, Figure 7D illustrates that the thimble member 86 can have a lip or ridge 87 on its upper end 88. The lip 87 can be adapted to fit over the upper end 67 of cartridge 62, or can be adapted to fit inside the cartridge 62 and thus assist in centering the filter device in the cartridge and at the same time space the outer walls of the filter device from the inner walls of the cartridge.

Figure 8, in combination with the cross- sectional views shown in Figures 9 and 10, depicts another alternate embodiment of a cartridge 90 which can be used with the present invention. The cartridge 90 can be used with any of the thimble filter members

described above (as can any of the cartridge members 100 and 110 described below) .

Cartridge member 90 has an annular ring member

92 integrally built or molded into its inner chamber which is used to center the thimble filter device positioned in it and also to space the filter device from the inner walls of the cartridge.

The cartridge 90 also has a handling ledge or lip 94 at its upper end and an integrally molded or built-in perforated support member 96 at its lower end.

Rather than supply an entire annular ring around the inner surface of the cartridge, a series or plurality of nubs or projections 98 could be provided instead. This is shown in Figure 11 with reference to cartridge 90' .

Figures 12-14 illustrate still further embodi¬ ments of cartridge devices which have means for center¬ ing and spacing thimble filter devices therein. Car¬ tridge 100, as shown in Figure 12, has a series or plurality of uniformly spaced angled ridges 102. Cartridge 110, as shown in Figures 13 and 14, has a plurality of elongated ribs or ridges 112 positioned along the inside surface.

Although all of the embodiments of the inven- tion described above utilize separation cartridges of circular cross-sections and thimble filter cups of generally circular cross-sections, it is to be under¬ stood that cartridges and filter cups of other cross- sectional sizes and shapes could be utilized and still

achieve the purposes and benefits of the present inven¬ tion. In this regard, representative additional sizes and cross-sectional shapes of the two components are shown in Figures 15A, 15B and 15C. In Figure 15A, the separation cartridge 120 has a square cross-section, while the filter cup 122 has a round or circular cross- section. In Figure 15B, the separation cartridge 124 has a round cross-section, while the filter cup 126 has a square cross-section. And, in Figure 15C, the separa- tion cartridge 128 has a round cross-section, while the filter cup 130 has a six-sided hexagonal cross-section. In each of these embodiments, the respective shapes of the components retain the filter cups in centered positions in the cartridges and also space the majority of the outer surfaces of the filter cups from the inner walls of the cartridges.

When the phase separation devices shown in Figures 5-15 are utilized, the material dissolved in an aqueous solution is introduced (manually or by an automatic system, such as a liquid handling robot) into the hollow interior cavity or chamber of the thimble filter device in the cartridge. If the material is extracted with a lower density solvent, then the materi¬ al will separate into a layer above the layer of water in the cartridge. The filter paper forming the thimble allows only the lighter-than-water organic solvents to penetrate and flow through the lower end of the car¬ tridge into the drying device 14. The material flows through the upper walls of the filter device (i.e. the upper portions of the walls above the level of water) and exits through the outlet 70.

Since the thimble filter devices are hydropho¬ bic, the devices shown in Figures 5-15 can be used for phase separation of any materials between an aqueous and organic solution, whether the solvents are lighter or heavier-than-water. In this regard, the devices depict¬ ed in Figures 5-15 can be utilized for the same solu¬ tions as the devices depicted in Figures 1-4, and can secure all of the same benefits and advantages.

With the present invention, the phase separa- tion device can also be used to wash aqueous soluble components out of a higher or lower density organic solvent to enable purification of organic materials.

While the best modes for carrying out the invention have been described in detail, those familiar with the art to which this invention relates will recognize various alternative designs and embodiments for practicing the invention as defined by the following claims .