Type 3 porous liquids

Abstract

This invention relates to a dispersion comprising porous particles dispersed in a liquid phase, wherein the porous particles comprise a zeolite and the liquid phase is a size-excluded liquid. The invention also relates to a method of adsorbing a gas into a liquid, comprising at least the step of bringing the gas into contact with the dispersion. In addition, the invention relates to an assemblage of the dispersion, the zeolite comprising a cavity and a gas contained within the cavity.

Claims

1. A dispersion comprising porous particles dispersed in a liquid, wherein the porous particles comprise a zeolite with a mean pore diameter of 1.9 Ångstroms to 4.0 Ångstroms and the liquid does not enter the pores of the zeolite.

2. The dispersion as claimed in claim 1, wherein the zeolite is selected from the group consisting of zeolite Rho, zeolite Na-Rho, ECR-18, ZSM-25 and PST-20.

3. The dispersion as claimed in claim 1, wherein the zeolite is zeolite Rho.

4. The dispersion as claimed in claim 1, wherein the liquid is selected from a glycol, 15-crown-5, trioctylamine, 2-(tert-butylamino)ethyl methacrylate, tributyl phosphate, dioctyl phthalate and bis(2-ethylhexyl) sebacate.

5. The dispersion as claimed in claim 4, wherein the glycol is a polyalkylene glycol.

6. The dispersion as claimed in claim 5, wherein the polyalkylene glycol is a polyethylene glycol or a polypropylene glycol.

7. The dispersion as claimed in claim 6, wherein the polyethylene glycol is selected from a polyethylene glycol dialkyl ether and a polyethylene glycol carboxylate.

8. The dispersion as claimed in claim 7, wherein the polyethylene glycol dialkyl ether is selected from a polyethylene glycol dimethyl ether and a polyethylene glycol dibutyl ether.

9. The dispersion as claimed in claim 1 comprising 0.1-50 wt % of the porous particles.

10. The dispersion as claimed in claim 9 comprising 10-30 wt % of the porous particles.

11. A method of adsorbing a gas into a liquid, comprising at least the step of bringing the gas into contact with a dispersion as claimed in claim 1.

12. The method of adsorbing a gas into a liquid as claimed in claim 11, wherein the gas is selected from CO.sub.2 and CH.sub.4.

13. A method of preparing a dispersion as claimed in claim 1, comprising at least the step of: mixing (i) porous particles comprising the zeolite, and (ii) the liquid.

14. An assemblage of a dispersion as claimed in claim 1, the zeolite comprising a cavity and a gas contained within the cavity.

15. The assemblage as claimed in claim 14, wherein the gas is selected from CO.sub.2 and CH.sub.4.

16. A dispersion comprising porous particles dispersed in a liquid phase, wherein the porous particles comprise a zeolite and the liquid phase is a size-excluded liquid, wherein the zeolite is selected from the group consisting of zeolite Rho, zeolite Na-Rho, ECR-18, ZSM-25 and PST-20.

17. The dispersion as claimed in claim 16, wherein the zeolite is zeolite Rho.

18. The dispersion as claimed in claim 16, wherein the size-excluded liquid is selected from the group consisting of a glycol, 15-crown-5, trioctylamine, 2-(tert-butylamino)ethyl methacrylate, tributyl phosphate, dioctyl phthalate and bis(2-ethylhexyl) sebacate.

19. The dispersion as claimed in claim 16 comprising 0.1-50 wt % of the porous particles.

20. The dispersion as claimed in claim 19 comprising 10-30 wt % of the porous particles.

Description

(1) FIG. 1A shows Powder X-Ray Diffraction (PXRD) data comparing the theoretical pattern for zeolite Rho and the pattern for the zeolite Rho made in the examples both before and after calcination at 500° C. for 8 hours,

(2) FIG. 1B shows PXRD data comparing as made zeolite Rho, Genosorb 1753, and 12.5 wt % and 25 wt % dispersions of zeolite Rho in Genosorb 1753,

(3) FIG. 2 shows a Scanning Electron Microscope (SEM) image of the as made zeolite Rho,

(4) FIG. 3 shows the CO.sub.2 uptake of Genosorb 1753 at three different temperatures and at pressures of from 1-5 bar,

(5) FIG. 4 shows the CO.sub.2 uptake of a 12.5 wt % dispersion of zeolite Rho in Genosorb 1753 at three different temperatures and at pressures of from 1-5 bar,

(6) FIG. 5 shows the CO.sub.2 uptake of a 25 wt % dispersion of zeolite Rho in Genosorb 1753 at three different temperatures and at pressures of from 1-5 bar,

(7) FIG. 6 shows the CO.sub.2 solubility of a 12.5 wt % dispersion of zeolite Rho in Genosorb 1753 before use, after use and regeneration at 25° C., and after use and regeneration at 50° C., and

(8) FIG. 7 shows a Parr reactor used in the high pressure gas update studies.

EXAMPLES

(9) Synthesis

(10) There are two reported methods to synthesize zeolite Rho according to literature. For the current study of zeolite Rho, method 1 was used to synthesize high crystallinity material.

(11) Method 1 (see Palomino et al, Chem. Commun., 2012, 48, 215-217): 18-crown-6 ether (4.70 g, 17.78 mmol), cesium hydroxide (3.53 g, 23.54 mmol) and sodium hydroxide (1.70 g, 42.50 mmol) were dissolved in 30 ml of deionised water. Sodium aluminate (6.60 g, 32.65 mmol) was added to this solution and stirred until fully dissolved. Ludox AS-40 colloidal silica (52.5 g, 873.8 mmol) was then added. The resulting mixture was stirred overnight at room temperature under atmospheric pressure. The obtained precursor mixture was then placed in a Teflon-lined stainless steel autoclave at 398K for 3 days for crystallization. The resulting zeolite Rho was then washed with deionised water by filtration until neutral and calcined at 773K for approximately 3 hours to remove the organic template (18-crown-6).

(12) Method 2 (see Mousavi et al, Ceramics International, 39 (2013), 7149-7158): Caesium hydroxide (1.91 g, 12.75 mmol) and sodium hydroxide (3.274 g, 81.75 mmol) were dissolved in 20 ml of deionised water. Sodium aluminate (3.94 g, 19.51 mmol) was added to this solution and stirred until fully dissolved. Ludox AS-40 colloidal silica (33.88 g, 563.9 mmol) was then added. The resulting mixture was stirred overnight at room temperature under atmospheric pressure. The obtained precursor mixture was then placed in a Teflon-lined stainless steel autoclave at 358K in an oil bath for 7 days for crystallization. The resulting zeolite Rho was then washed with deionised water by filtration until neutral.

(13) Method 3: Caesium hydroxide (1.91 g, 12.75 mmol) and sodium hydroxide (3.274 g, 81.75 mmol) were dissolved in 20 ml of deionised water. Sodium aluminate (3.94 g, 19.51 mmol) was added to this solution and stirred until fully dissolved. Ludox AS-40 colloidal silica (33.88 g, 563.9 mmol) was then added. 400 mg of crystalline zeolite Rho (seeding) was then added to the resulting mixture and stirred overnight at room temperature under atmospheric pressure. The obtained precursor mixture was then placed in a Teflon flask at 358K in oil bath for 7 days for crystallization. The resulting zeolite Rho was then washed with deionised water by filtration until neutral.

(14) The zeolite Rho data below is a result of testing carried out on material made by Method 1.

(15) The dispersion (also sometimes referred to as a “porous liquid”) was prepared by mixing Genosorb 1753 and zeolite Rho by stirring the components in laboratory flask until formation of homogeneous dispersion, typically about 15 mins. Other missing techniques such as grinding, milling or sonicating can also be used.

(16) Characterisation

(17) The zeolite Rho-Genosorb 1753 porous liquid was characterized by Powder X-Ray Diffractometer (PXRD), Thermo-gravimetric Analysis (TGA) and Infrared Spectroscopy (IR). The PXRD spectrum of zeolite Rho in Genosorb porous liquid (see FIG. 1B) shows an identical pattern to that of the original zeolite Rho (see both FIGS. 1A and 1B). This confirms that the zeolite components remain intact and crystalline after mixing with Genosorb.

(18) An SEM image of the original zeolite Rho (ie not as a dispersion) is shown in FIG. 2. This demonstrates that the particle size is around 1.0-1.2 μm.

(19) Gas Uptake Studies

(20) Low pressure measurement (c.a. 0.8 bar condition; 25° C.)—Gas solubility studies were carried out by using a volumetric technique based on an isochoric method (see S. L. James et. al.; Nature, 527, 216).

(21) All the measurements were carried out at around 0.8 bar and 298K. The results show that the addition of zeolite Rho to commercial solvent Genosorb 1753 increases the CO.sub.2/CH.sub.4 selectivity significantly (see Table 1 below). The zeolite Rho does not lose its gas capacity and the gas uptake is predictable.

(22) TABLE-US-00001 TABLE 1 12.5 wt % 25 wt % Genosorb Zeolite Rho in Zeolite Rho in 1753 Genosorb Genosorb CO.sub.2 solubility* 0.209 mmol/g 0.475 mmol/g 0.738 mmol/g (9.234 mg/g) (20.923 mg/g) (32.499 mg/g) CH.sub.4 solubility 0.055 mmol/g 0.043 mmol/g 0.027 mmol/g (0.882 mg/g) (0.6463 mg/g) (0.4383 mg/g) CO.sub.2/CH.sub.4 c.a. 3.8 c.a. 10.32 c.a. 23.06 *from large volume gas rig (V2) from small volume gas rig (V1), error is large due to small amount of CH.sub.4 uptake

(23) High Pressure measurement (1-5 bar, 25° C.-75° C.)—High pressure gas solubility studies were carried out by using Parr reactor based on a mass flow (see A. M. Orozco et. al., Industrial Crops and products, 2013, 44, 1 for a similar experimental set-up).

(24) All the measurements were carried out from 1 to 5 bar at 298K, 323K and 348K. The high pressure measurements also show predictable outcomes. Table 2 below, and FIGS. 3-5, show the CO.sub.2 uptake of Genosorb 1753, a 12.5 wt % dispersion of zeolite Rho in Genosorb 1753 and a 25 wt % dispersion of zeolite Rho in Genosorb 1753. Table 3 below shows the experimental values for pure zeolite Rho at 298K, plus the predicted values for the 12.5 wt % zeolite Rho in Genosorb 1753 and 25 wt % zeolite Rho in Genosorb 1753 dispersions.

(25) The measured CO.sub.2 solubility of the dispersions is comparable to its predicted value at low pressure but slightly less than the predicted value at high pressure. The high pressure gas uptake measurements show that the addition of zeolite Rho to Genosorb 1753 solvent significantly enhances CO.sub.2 uptake and the operational range for a temperature pressure swing adsorption/desorption system.

(26) TABLE-US-00002 TABLE 2 12.5 wt % Zeolite 25 wt % Zeolite Genosorb Rho in Genosorb Rho in Genosorb 298K 323K 348K 298K 323K 348K 298K 323K 348K 1 5.478 5.044 3.669 16.457 11.476 7.919 30.024 21.639 15.234 bar 2 11.331 9.687 7.423 29.015 19.852 14.160 48.327 33.558 24.342 bar 3 17.493 14.571 11.727 35.968 36.580 19.339 58.322 41.623 30.804 bar 4 24.221 19.598 16.206 42.717 32.829 24.000 65.377 50.361 36.102 bar 5 31.471 25.089 20.853 49.862 37.909 29.408 72.444 58.028 41.274 bar

(27) TABLE-US-00003 TABLE 3 298K Experimental Theoretical 12.5 Theoretical 25 pure Zeolite Rho wt % Zeolite Rho wt % Zeolite Rho 1 bar 108.12 18.31 31.14 2 bar 170.00 31.16 51.00 3 bar 200.57 40.38 63.26 4 bar 216.69 48.28 72.34 5 bar 228.68 56.12 80.77

(28) Reversibility/Regeneration

(29) Ease of material regeneration is a useful property which can provide a reduction in regeneration cost. It is difficult to achieve by amine-based technology nowadays due to the high energy penalty. The dispersions of the invention are understood to be easily regenerated by applying mild heating or vacuum. As shown in FIG. 6, the porous liquid (12.5 wt % zeolite RHO in Genosorb 1753) shows about a 62.5% recovery in CO.sub.2 uptake capacity when it has undergone a room temperature regeneration under vacuum for 30 minutes. However, CO.sub.2 uptake capacity recovers to around 92% when the same regeneration conditions are used, but the temperature is increased to 50° C.

(30) Additional CO.sub.2 Uptake Studies

(31) Further dispersions comprising combinations of porous particles with various liquids were prepared by mixing the porous particles with the liquid as described above. The dispersions produced, and their theoretical and actual CO.sub.2 uptake values in mg/g, are shown in Tables 4a-c below.

(32) TABLE-US-00004 TABLE 4a Polyethylene Polyethylene Polyethylene Polyethylene glycol glycol dimethyl glycol dimethyl glycol dimethyl dibutyl ether ether (Genosorb ether (Genosorb ether (Genosorb (Genosorb 1843) - 1753) - CO.sub.2 uptake 300) - CO.sub.2 uptake 1900) - CO.sub.2 uptake CO.sub.2 uptake mg/g mg/g (mmol/g) mg/g (mmol/g) mg/g (mmol/g) (mmol/g) Wt % Exp. Cal. Exp. Cal. Exp. Exp. Cal. Cal.  9.23  5.64 6.7 7.3  (0.21)  (0.13)  (0.15)  (0.17) Zeolite 12.5 22.58 22.64 16.18 18.61 15.93  19.6   19.24 20.14 Rho  (0.51)  (0.51)  (0.37)  (0.42)  (0.36)  (0.45)  (0.44)  (0.46) 25   33.2  33.6  — — — — — —  (0.75)  (0.76) PAF-1 12.5 31.91 31.23 — — — — — —  (0.76)  (0.71) ZIF-8 12.5  5.64 13.04 — — — — — —  (0.13)  (0.30) Al(fum) 12.5 11.78 20.12 — — — — — — (OH)  (0.27)  (0.46) Polypropylene glycol - CO.sub.2 uptake mg/g (mmol/g) Wt % Exp. Cal. Zeolite Rho 12.5  15.69   18.96   (0.36)  (0.43) 25   — — PAF-1 — — ZIF-8 — — Al(fum)(OH) — —

(33) TABLE-US-00005 TABLE 4b polyethylene glycol dibenzoate - CO.sub.2 uptake Polyethylene glycol bis(2-ethylhexanoate) - CO.sub.2 mg/g (mmol/g) uptake mg/g (mmol/g) Wt % Exp. Cal. Exp. Cal. 2.8 7.91 (0.063) (0.18) Zeolite Rho 12.5 16.65 17.01 14.23 21.48 (0.39) (0.39) (0.33) (0.49) 25   — — — — ZIF-8 12.5 6.7 7.05 11.30 11.52 (0.15) (0.16) (0.26) (0.26) 25   — — 14.84 15.13 Al(fum)(OH) 12.5 — — — — Zeolite 10A 12.5 — — — —             0 poly(ethylene glycol) dimethacrylate - CO.sub.2 15-crown-5 - CO.sub.2 uptake Silicone oil (50cst) - CO.sub.2 uptake mg/g (mmol/g) mg/g (mmol/g) uptake mg/g (mmol/g) Wt % Exp. Exp. Exp. Cal. Exp. Cal. 4.53 4.37 9.38 (0.10) (0.099) (0.21) Zeolite Rho 12.5 — — 18.71 17.57 20.23 18.92 (0.43) (0.40) (0.46) (0.43) 25   — — — — — — ZIF-8 12.5 7.41 8.91 4.40 9.68 9.68 9.24 (0.17) (0.20) (0.10) (0.22) (0.22) (0.21) 25   — — — — — — Al(fum)(OH) 12.5 — — — — 15.84 16.28 (0.36) (0.37) Zeolite 10A 12.5 — — — — 20.25 20.68 (0.46) (0.47)

(34) TABLE-US-00006 TABLE 4c     Trioctylamine - CO.sub.2 2-(tert-butylamino)ethyl uptake mg/g methacrylate - CO.sub.2 uptake (mmol/g) mg/g (mmol/g) Wt % Exp. Cal. Exp. Cal. 2.92 6.33 (0.066) (0.14) Zeolite 12.5 18.85 17.12 15.44 20.10 Rho (0.43) (0.39) (0.35) (0.46)       Tributyl phosphate - CO.sub.2 uptake mg/g Dioctyl phthalate - CO.sub.2 uptake mg/g (mmol/g) (mmol/g) Wt % Exp. Exp. Exp. Cal. 2.65 3.54 (0.06) (0.09) Zeolite 12.5 17.65 16.88 18.71 17.66 Rho (0.40) (0.38) (0.43) (0.40) Bis(2-ethylhexyl) sebacate - CO.sub.2 uptake mg/g (mmol/g) Exp. Cal.   9.38   (0.21) Zeolite 12.5  23.65   22.77  Rho  (0.54)  (0.52)

(35) CH.sub.4 Uptake

(36) CH.sub.4 uptake of the dispersions was also investigated and the results are shown in Table 5 below. This was carried out using the isochoric method described above (ie S. L. James et. al.; Nature, 527, 216).

(37) TABLE-US-00007 TABLE 5 Table 4c Tributyl phosphate - Polypropylene glycol - CH.sub.4 uptake mg/g CH.sub.4 uptake mg/g (mmol/g) (mmol/g) Wt % Exp. Cal. Exp. Exp. — 0.457 (0.028) Zeolite 12.5 0.181 — 0.466 0.502 Rho (0.011) (0.029) (0.031) 25   — — 0.506 0.547 (0.031) (0.034)

(38) Selectivity

(39) Selectivity is estimated by ratio (A.sub.mmol/g/B.sub.mmol/g). Values for CO.sub.2 selectivity over CH.sub.4 (CO.sub.2/CH.sub.4) were calculated for two of the dispersions and the results are shown in Table 6 below.

(40) TABLE-US-00008 TABLE 6   Tributyl phosphate - Polypropylene glycol - CO.sub.2/CH.sub.4 selectivity CO.sub.2/CH.sub.4 selectivity (by 1:1 ratio) (by 1:1 ratio) Wt % Exp. Cal. Exp. Exp. — c.a. 7.5  Zeolite 12.5 c.a. 36.4 — c.a. 17.6 c.a. 16.5 Rho 25   — — c.a. 24.1 c.a. 22.4