Carbon Molecular Sieves and Spherical Graphitized Polymer

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Carbon Molecular Sieves and Spherical Graphitized Polymer Carbons for Sample Preparation Processes and Bulk Scale Purification ProcessesWilliam R. Betz, Michael J. Keeler, Jay M. Jones, Wendy S. Roe, and Michael D. BuchananSupelco, Div. of Sigma-AldrichBellefonte, PA 16823 USA

T414109

© 2012 Sigma-Aldrich Co. All rights reserved.© 2014 Sigma-Aldrich Co. All rights reserved.

Introduction

High purity, spherical graphitized polymer carbons (SGPC) and spherical, high purity carbon molecular sieves (CMS) have been synthesized for use in sample preparation processes and bulk-scale purification processes. The use of new SGPC and CMS particles in packed bed systems and coated devices provides a recent advancement in these technologies. Graphitized carbon blacks (granular) also provide recent advances in these technologies.These carbons have also found uses in bulk-scale purification processes.

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Materials and Methods

Spherical CMS particles have been synthesized for sample preparation analyses and bulk scale purification processes. For example, a 2.0 μm CMS with a large microporous regime allowed for the preparation of coated surfaces for the extraction and subsequent analyses of small molecular sized, airborne contaminants. These CMS particles with sub-10 µm particle sizes have been bonded to glass, metal and plastic substrates using patented, proprietary adhesives (1,2). These applications focused also on a range of analytes from light gases to the semi-volatiles in aqueous environments. The surface chemistries of several 50 μm and 600 μm CMS particles have been applied to bulk extraction processes. SGPC particles have also been synthesized which possess a wide range of textural properties and surface chemistries. For example, 50 μm monodispersed SGPC particles possessing surface areas of 20 m2/g and 100 m2/g (3) have been effective in improving the adsorption and flow characteristics of a solid phase extraction (SPE) device for planar pesticides, pesticide, insecticide and herbicide analyses. SGPC particles with sub-10 µm particle sizes have also been bonded to glass, metal and plastic substrates using patented, proprietary adhesives for sample preparation applications. 3


Materials and Methods (contd.)

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Spherical CMS and SGPC particles have also been synthesized for bulk scale purification processes such as pharmaceutical compound purification. The tailoring of the carbon pore structure and surface chemistry (range from pH = 3.0-11.0) allow for selective purification processes.


Results and Discussion

Figure 1 provides a low resolution SEM photograph of the 20 m2/g SGPC for planar pesticide analyses using dispersive SPE technology. The recovery of the planar pesticides has been an inherent 30 year problem for the US EPA, with recoveries less than 15%. This carbon provides a greater than 80% recovery for the planar pesticides, including hexachlorobenzene.

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Sample Preparation Data

Figure 1. 50 μm SGPC for Planar Pesticides (20 m2/g)


Figure 2 illustrates a 100 m2/g SGPC with a 50 µm monodispersed particle size distribution. This SGPC has been effective in improving the adsorption and flow characteristics of a solid phase extraction (SPE) device for pesticide, insecticide and herbicide analyses. A low resolution SEM photograph of the SGPC carbon is presented.

Figure 2. 50 μm SGPC for Pesticides (100 m2/g)

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Results and Discussion (contd.)Sample Preparation Data


Amorphous CMS carbons with surface areas of 800-1300 m2/g have been effective for use in SPE applications focused on small, polar molecules such as small, polar pesticides. Figure 3 illustrates one of these 20-40 μm CMS carbons. Figures 4-6 illustrate 2 additional ultra-microporous CMS carbons for use in small molecule adsorption processes. These carbons are used for small polar molecules (e.g., Propylene Glycol) extracted from aqueous matrices, and small gas phase molecules such as methane, ethane, propyne, propylene and propane.

Figure 3. 20-40 μm CMS Carbon (1300 m2/g)

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Figure 6. DFT Overlay of 50-75 μm CMS Carbons

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A second example is a family of these carbons, with surface areas ranging from one to two hundred meters per gram. SGPC particles with sub-10 µm particle sizes have been bonded to glass, metal and plastic substrates using patented, proprietary adhesives (1,2), as illustrated in Figures 7-9. These coated devices are used for air sampling of chemical and biological warfare agents.

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2 patented adhesives (Siloxane-1997 and Silazane-2011)

Figure 7. Nano-GPC Coated Screen

Figure 8. Spherical, sub-10 µm CMS

Figure 9. Nano-GCB

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Spherical CMS and GPC particles have also been synthesized for bulk-scale purification processes such as pharmaceutical impurities removal. Both cartridge and bulk-addition processes have been evaluated for effectiveness. Also, the tailoring of the carbon pore structure and surface chemistry (range from pH = 3.0-11.0) allow for selective purification processes. Table 1 provides a list of the bulk-scale carbons.

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Results and Discussion (contd.)Bulk-Scale Purification Data


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Table 1. A List of High Purity Scalable CarbonsCarbon Name Carbon Description Particle Shape BET Surface Area

(m2/g)Carboxen® 1003 Carbon Molecular Sieve Spherical 1000Carboxen 1005 Carbon Molecular Sieve Spherical 1150Carboxen 1030 Carbon Molecular Sieve Spherical 700Carboxen 1032 Carbon Molecular Sieve Spherical 820Carboxen 1033 Carbon Molecular Sieve Spherical 430Carboxen 1034 Carbon Molecular Sieve Spherical 1260Carboxen 563 Carbon Molecular Sieve Spherical 510Carboxen 564 Carbon Molecular Sieve Spherical 400Carboxen 569 Carbon Molecular Sieve Spherical 485Carboxen 572 Carbon Molecular Sieve Spherical 1100

Graphsphere 2017 Spherical Graphitized Polymer Carbon Spherical 61

Carbotrap® B Graphitized Carbon Black Granular 100Carbotrap C Graphitized Carbon Black Granular 10Carbotrap F Graphitized Carbon Black Granular 5Carbotrap X Graphitized Carbon Black Granular 240Carbotrap Y Graphitized Carbon Black Granular 24

Results and Discussion (contd.)


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The surface chemistries of the carbon molecular sieves can be adjusted to provide a range of pH and meq/g values. Table 2 provides an example of the pH ranges of these carbons.



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Table 2. A List of High Purity Scalable Carbons with pH Values Highlighted

Carbon Name Carbon Description Particle Shape BET Surface Area (m2/g)

pHSpecific

Carboxen 1003 Carbon Molecular Sieve Spherical 1000Carboxen 1005 Carbon Molecular Sieve Spherical 1150Carboxen 1030 Carbon Molecular Sieve Spherical 700Carboxen 1032 Carbon Molecular Sieve Spherical 820 3.0Carboxen 1033 Carbon Molecular Sieve Spherical 430 7.0Carboxen 1034 Carbon Molecular Sieve Spherical 1260 10.0Carboxen 563 Carbon Molecular Sieve Spherical 510Carboxen 564 Carbon Molecular Sieve Spherical 400Carboxen 569 Carbon Molecular Sieve Spherical 485Carboxen 572 Carbon Molecular Sieve Spherical 1100Graphsphere

2017Spherical Graphitized

Polymer Carbon Spherical 61

Carbotrap B Graphitized Carbon Black Granular 100Carbotrap C Graphitized Carbon Black Granular 10Carbotrap F Graphitized Carbon Black Granular 5Carbotrap X Graphitized Carbon Black Granular 240Carbotrap Y Graphitized Carbon Black Granular 24



An application example of a CMS used in a cartridge for removal of impurities present in methanol is provided below in Figures 10-12.

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1818

0 10 20 30Time (min)

0.00

E+0

02.

00E

+06

Abu

ndan

ce Bottled Methanol (Organic Impurities)

C11 hydrocarbon

Fatty acid methyl esters (C16-C18)

0 10 20 30Time (min)

0.00

E+0

02.

00E

+06

Abu

ndan

ce

Bulk Tank Methanol (Organic Impurities)C11 hydrocarbon

Fatty acid methyl esters (C16-C18)

0 10 20 30Time (min)

0.00

E+00

2.00

E+06

Abun

danc

e

Carbon Treated Bulk Tank Methanol

(100 Gallons Methanol; 300 g Carboxen-1005 Cartridge)

Figures 10-12. GC-MS Data Illustrating Impurities Removal From Methanol



Conclusions

High purity, spherical graphitized polymer carbons (SGPC), spherical, high purity carbon molecular sieves (CMS) and granular high purity, nano-graphitized carbon blacks (GCB) have been synthesized for use in chromato-graphic, sample preparation processes and bulk extraction processes. The use of carbons in gas and liquid chromatography as well as samples preparation applications has been realized for several decades. Continued advancements in the carbon synthesis technology have led to improving these applications, specifically the detection levels required for effective trace-level analyses.

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References

1. Betz, W. and J. Desorcie, Nucleophilic Bodies Bonded to Siloxane and Use Thereof for Separations from Sample Matrices, Japan Patents JP3913760, JP4016051, US Patents US05599445, US05607580, US05609756, US05620603, US05630937.

2. Betz, W. and C. Linton, Polysilazane Thermosetting Polymers for Use inChromatographic Systems and Applications, US7815864, US8088350, US8092770, US7875738.

3. Webb, P.A. and Orr, C., Analytical Methods in Fine Particle Technology. Micromeritics, Norcross, GA, 1997.

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Carbon Molecular Sieves and Spherical Graphitized Polymer