Combining Molecular Sieve and Complexing Properties of the Column Packing in Gas Chromatography

Influence of modifying pentasyl group synthetic zeolites (Silicalite-1 and Silicalite-2) with metal cations capable to specific interactions on the separation ability of the chromatographic column has been studied.

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Дата:2010
Автори: Eprikashvili, L., Pirtskhalava, N., Andronikashvili, T., Kordzakhia, T., Zautashvili, M., Dzagania, M.
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Мова:English
Опубліковано: Інститут хімії поверхні ім. О.О. Чуйка НАН України 2010
Назва видання:Хімія, фізика та технологія поверхні
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Цитувати:Combining Molecular Sieve and Complexing Properties of the Column Packing in Gas Chromatography / L. Eprikashvili, N. Pirtskhalava, T. Andronikashvili, T. Kordzakhia, M. Zautashvili, M. Dzagania // Хімія, фізика та технологія поверхні. — 2010. — Т. 1, № 3. — С. 292-295. — Бібліогр.: 15 назв. — англ.

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spelling nasplib_isofts_kiev_ua-123456789-289952025-02-09T14:58:35Z Combining Molecular Sieve and Complexing Properties of the Column Packing in Gas Chromatography Поєднання молекулярно-ситових і комплексоутворюючих властивостей насадок в газовій хроматографії Сочетание молекулярно-ситовых и комплексообразующих свойств насадок в газовой хроматографии Eprikashvili, L. Pirtskhalava, N. Andronikashvili, T. Kordzakhia, T. Zautashvili, M. Dzagania, M. Функціоналізовані матеріали, одержані золь-гель і темплатним методами Influence of modifying pentasyl group synthetic zeolites (Silicalite-1 and Silicalite-2) with metal cations capable to specific interactions on the separation ability of the chromatographic column has been studied. Вивчено вплив модифікування синтетичних цеолітів сімейства пентасілів (Сілікаліту-1 і Сілікаліту-2) катіонами металів, здатних до специфічних взаємодій, на розділювальну здатність хроматографічної колонки. Изучено влияние модифицирования синтетических цеолитов семейства пентасилов (Силикалита-1 и Силикалита-2) катионами металлов, способными к специфическим взаимодействиям, на разделительную способность хроматографической колонки. 2010 Article Combining Molecular Sieve and Complexing Properties of the Column Packing in Gas Chromatography / L. Eprikashvili, N. Pirtskhalava, T. Andronikashvili, T. Kordzakhia, M. Zautashvili, M. Dzagania // Хімія, фізика та технологія поверхні. — 2010. — Т. 1, № 3. — С. 292-295. — Бібліогр.: 15 назв. — англ. 2079-1704 https://nasplib.isofts.kiev.ua/handle/123456789/28995 543.544 en Хімія, фізика та технологія поверхні application/pdf Інститут хімії поверхні ім. О.О. Чуйка НАН України
institution Digital Library of Periodicals of National Academy of Sciences of Ukraine
collection DSpace DC
language English
topic Функціоналізовані матеріали, одержані золь-гель і темплатним методами
Функціоналізовані матеріали, одержані золь-гель і темплатним методами
spellingShingle Функціоналізовані матеріали, одержані золь-гель і темплатним методами
Функціоналізовані матеріали, одержані золь-гель і темплатним методами
Eprikashvili, L.
Pirtskhalava, N.
Andronikashvili, T.
Kordzakhia, T.
Zautashvili, M.
Dzagania, M.
Combining Molecular Sieve and Complexing Properties of the Column Packing in Gas Chromatography
Хімія, фізика та технологія поверхні
description Influence of modifying pentasyl group synthetic zeolites (Silicalite-1 and Silicalite-2) with metal cations capable to specific interactions on the separation ability of the chromatographic column has been studied.
format Article
author Eprikashvili, L.
Pirtskhalava, N.
Andronikashvili, T.
Kordzakhia, T.
Zautashvili, M.
Dzagania, M.
author_facet Eprikashvili, L.
Pirtskhalava, N.
Andronikashvili, T.
Kordzakhia, T.
Zautashvili, M.
Dzagania, M.
author_sort Eprikashvili, L.
title Combining Molecular Sieve and Complexing Properties of the Column Packing in Gas Chromatography
title_short Combining Molecular Sieve and Complexing Properties of the Column Packing in Gas Chromatography
title_full Combining Molecular Sieve and Complexing Properties of the Column Packing in Gas Chromatography
title_fullStr Combining Molecular Sieve and Complexing Properties of the Column Packing in Gas Chromatography
title_full_unstemmed Combining Molecular Sieve and Complexing Properties of the Column Packing in Gas Chromatography
title_sort combining molecular sieve and complexing properties of the column packing in gas chromatography
publisher Інститут хімії поверхні ім. О.О. Чуйка НАН України
publishDate 2010
topic_facet Функціоналізовані матеріали, одержані золь-гель і темплатним методами
url https://nasplib.isofts.kiev.ua/handle/123456789/28995
citation_txt Combining Molecular Sieve and Complexing Properties of the Column Packing in Gas Chromatography / L. Eprikashvili, N. Pirtskhalava, T. Andronikashvili, T. Kordzakhia, M. Zautashvili, M. Dzagania // Хімія, фізика та технологія поверхні. — 2010. — Т. 1, № 3. — С. 292-295. — Бібліогр.: 15 назв. — англ.
series Хімія, фізика та технологія поверхні
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fulltext Хімія, фізика та технологія поверхні. 2010. Т. 1. № 3. С. 292–295 _____________________________________________________________________________________________ 292 ХФТП 2010. Т. 1. № 3 UDC 543.544 COMBINING MOLECULAR SIEVE AND COMPLEXING PROPERTIES OF THE COLUMN PACKING IN GAS CHROMATOGRAPHY L. Eprikashvili, N. Pirtskhalava, T. Andronikashvili, T. Kordzakhia, M. Zautashvili, M. Dzagania Melikishvili Institute of Physical and Organic Chemistry of Georgia 5 Jikia Street, Tbilisi 0186, Georgia, physorgchem@pochta.ru Influence of modifying pentasyl group synthetic zeolites (Silicalite-1 and Silicalite-2) with metal cations capable to specific interactions on the separation ability of the chromatographic column has been studied. INTRODUCTION Zeolites belong to the selective sorbents which strongly adsorb some compounds (normal chained hydrocarbons) but do not adsorb others (aromatic, cyclic) depending on the configuration of the ad- sorbate molecule. The selectivity of zeolites is due to their molecular sieve properties [1]. The use of zeolites in gas chromatography ensures the separa- tion of a complex mixture of oil origin [2]. Mixtures of meta-, ortho- and para-isomers of different hydrocarbons are difficult to separate. For their separation, such sorbents as Benton-34 and liquid crystal phases are known to be used [3, 4]. The selectivity of adsorbents is probably due to their structural properties. Zeolite Silikalite also exhibits increased selectivity to para-isomers. Be- cause of its molecular sieve properties, it can retain linear molecules of para-isomers and does not ad- sorb ortho- and meta-isomers [5–8]. In this paper, we present the results of studying a selective adsorbent that combines molecular sieve properties with complexation properties, namely, a zeolite (Silicalite) modified with metal cations capable of forming complexes with benzene hydrocarbons. EXPERIMENTAL Two samples of Silicalite: Silicalite-1 (analog of ZSM-5) and Silicalite-2 (analog of ZSM-11) from the pentasyl group have been investigated [9]. These zeolites are characterized by an ideal unit cell of the following composition: Nan(Al nSi96-nO192)~16H2O n~3 [10]. The adsorbents studied are high-silica zeo- lites. In contrast to conventional zeolites, they exhibit hydrophobic properties. The structures of both zeolites are almost identi- cal: ten-membered rings form two systems of inter- secting channels lying in perpendicular planes. The main difference between them is as follows: in Sili- calite-1, the two channel systems bearing oxygen rings of the size 0.51–0.56 nm are of both round – shape and ellipsoid configuration whereas all rings in Silikalite-2 possess ellipsoid configurations of the size 0.54x0.56 nm [10]. Barrer in [10] believed that even such a small difference in zeolite structures could strongly affect their adsorption properties. In our experiments, powders of Silikalite-1 and Silikalite-2 (the Silikalite sample was synthesized at the Center for porous Materials of Manchester and kindly provided by Dr. R.J. Paisted) were modified with cad- mium, thallium, and silver cations by ion exchange [11]. These cations can form unstable complexes with some benzene compounds. In the course of modification, the initial sodium forms of Silikalites were treated three times with a 0.1 M solution of corresponding metal nitrates. After each treatment, the powder was washed with distilled water to re- move excess sodium cations and then dried at 150°C for four to six hours. In the chromatography column, zeolite was used in the surface-layer ver- sion [12] that is a powder of dispersity of 25–60 µm applied onto a solid support, celite-545, grains 60–80 mesh using the procedure proposed by Bom- bauch [13]. The zeolite and solid support (1:2) were mixed in a rotating porcelain cylinder. In the result- ing adsorbent, the fraction of zeolite was ~27–29% relative to the mass of the solid support. The experiments were conducted on LKhM- 8MD Model 3 chromatograph using a column of 0.5 m in length and 3 mm in inside diameter. The adsorbent packed in the column was thermally activated by heating the column to 250°C in a Combining Molecular Sieve and Complexing Properties of the Column Packing _____________________________________________________________________________________________ ХФТП 2010. Т. 1. № 3 293 flow of a carrier gas (nitrogen) for 4–6 h. Column temperature in the experiments was maintained at 230°C under isothermal conditions. The flow rate of the carrier gas (nitrogen) was of 50 mL/min. A flame ionization detector was used. Model test mixtures consisted of the following isomers: (1) meta-, ortho-, and para-xylenes; (2) meta-, ortho-, and para-chlorotoluenes; (3) meta-, ortho-, and para-dichlorobenzenes; (4) para-xylene, para-chlortoluene, and para-dichlorobenzene. We determined parameters characterizing the process of chromatographic separation [14]. RESULTS AND DISCUSSION Table 1 presents relative retention times of all the studied compounds and corresponding asymmetry coefficients of chromatographic peaks on both the initials (sodium) forms of Silikalites and cation- exchanger forms. As can be seen in Table 1, selectiv- ity to para-isomers for all the studied compounds was much higher them that to ortho- and meta- isomers of the same triad. The retention times of these isomers were almost equal. In going to cation- exchanger forms, the retention times of ortho-, meta-, and para-isomers increased in the order Na<Cd<Tl<Ag, depending on the nature of the cation incorporated into the Silikalite. The increase was more pronounced for para-isomers and less pro- nounced for ortho- and meta-isomers. This effect was enhanced as the molecular mass of compounds was increased. The asymmetry coefficients for ortho- and meta-isomers insignificantly changed depending on the isomery and the type of the cation-modified form; a noticeable increase was observed for para-isomers. According to the tabular data, relative reten- tion times of the components on Silicalite-2 are higher as compared to those on Silicalite-1 on average by 170% and they are higher on both on the initial (sodium) and cation (Cd+2, Tl+, and Ag+) modified forms; as for the asymmetry coef- ficients, they are higher, i.e. Кас→1. By comparing retention times, we calculated the increase in selectivity of the retention of para- isomers compared to ortho-isomers cation-exchanger forms of Silikalites (Table 2).The data in Table 2 indicate that, for all isomers, selectivity increases in the order Cd<Tl<Ag depending on the cation nature in comparison with initial (sodium) forms. As was shown in our earlier paper [15], the in- troduction of Cd and Ag cations into type X zeo- lites significantly increased the retention volumes for unsaturated hydrocarbons in comparison to those for saturated ones. This effect was more pro- nounced for silver- than for cadmium-containing zeolite and be explained by the formation of two complexes differing in stability. Thus, the interac- tion of AgX with ethylene proceeds as overlapping of two orbitals, the occupied π orbital of ethylene with the vacant 5sp orbital of the silver ion and the occupied 4d orbital of silver with the vacant π* orbital of ethylene. In the case of CdX, interaction proceeds as overlapping of only π and 5sp orbitals. It is likely that, for the studied isomeric benzene derivatives, π bonds the benzene rings of isomers also interact with corresponding orbitals of Cd, Tl, and Ag cations to form complexes differing in stabil- ity (it increases in the above order) which results in an increase in the retention volumes of all isomers. A significant increase in the selectivity of the adsorbent to para-isomers is due to the molecular sieve properties of the zeolite which more strongly adsorbs these isomers because of their configuration. As a result, the rate of molecular diffusion, which is also determined by the nature of the radical at the benzene ring, decreases. The data in Table 2 also indicate that the se- lectivities of thallium- and silver-containing Silikalits to para-isomers are very high and al- most equal. This can be explained by the fact that the physical and chemical properties of Tl + and Ag + cations are similar [12]. Thus, we can conclude that the selectivity of cation-modified Silikalites to para-isomers is deter- mined by two factors: (1) the effect of molecular sieves and (2) the ability of analytes to form complexes with cadmium, thallium, and silver cations whereas only the complexation effect is responsible for the adsorb- ent selectivity to ortho- and para-isomers. As follows from aforesaid, cation-modified Silikalites, in particular, those containing thallium and silver ions can be attributed to adsorbents selective to para-isomers. The values of the criterion of uniformity of separation ∆ [14] of a model ternary mixture of para-isomers on the studied adsorbents are pre- sented in Table 3. It can be seen that the sharpness of the sepa- ration of the model mixture increases in the above order depending on the cation nature. Both in- crease in the retention times of the individual components and more symmetrical peaks (Ta- ble 1) on Silicalite-2 compared to those on Sili- calite-1 define higher values of the criterion of uniformity on Silicalite-2 (Table 3). L. Eprikashvili, N. Pirtskhalava, T. Andronikashvili et al. _____________________________________________________________________________________________ 294 ХФТП 2010. Т. 1. № 3 Table 1. Relative retention times (t / R) of some benzene derivatives and asymmetry coefficients of chromatographic peaks (Kas) of corresponding compounds [14] (column temperature 230°C) Adsorbent initial (so- dium) form of Silikalite-1 applied onto celite-545 initial (so- dium) form of Silikalite-2 applied onto celite-545 cadmium form of Silikalite-1 applied onto celite-545 cadmium form of Silikalite-2 applied onto celite-545 thallium form of Silikalite-1 applied onto celite-545 thallium form of Silikalite-2 applied onto celite-545 silver form of Silikalite-1 applied onto celite-545 silver form of Silikalite-2 applied onto celite-545 Compound t/ R Kas t/ R Kas t/ R Kas t/ R Kas t/ R Kas t/ R Kas t/ R Kas t/ R Kas benzene 1.00 0.77 1.00 0.82 1.00 0.72 1.00 0.80 1.00 0.67 1.00 0.78 1.00 0.64 1.00 0.76 o-xylene 0.37 0.77 1.12 0.80 0.34 0.75 1.15 0.77 0.23 0.73 1.17 0.75 0.24 0.70 1.22 0.73 m-xylene 0.43 0.75 1.17 0.78 0.39 0.70 1.25 0.75 0.25 0.67 1.27 0.73 0.27 0.65 1.29 0.70 p-xylene 0.89 0.70 2.23 0.75 1.14 0.67 2.70 0.73 0.89 0.65 2.87 0.70 0.89 0.63 2.89 0.67 o- chlorotoluene 0.43 0.75 1.28 0.77 0.39 0.73 1.30 0.75 0.29 0.70 1.39 0.73 0.30 0.67 1.41 0.70 m- chlorotoluene 0.49 0.73 1.39 0.75 0.41 0.70 1.41 0.73 0.35 0.67 1.52 0.70 0.34 0.64 1.56 0.67 p- chlorotoluene 1.31 0.67 2.89 0.73 1.48 0.65 3.45 0.70 1.72 0.64 5.83 0.67 1.72 0.60 5.89 0.65 o- dichlorobenzene 0.54 0.70 1.56 0.74 0.64 0.67 1.58 0.70 0.40 0.63 1.65 0.67 0.43 0.61 1.78 0.65 m- dichlorobenzene 0.49 0.67 1.50 0.70 0.59 0.65 1.58 0.67 0.37 0.60 1.61 0.65 0.38 0.57 1.71 0.63 p- dichlorobenzene 1.94 0.65 4.06 0.68 1.70 0.63 4.75 0.65 2.63 0.57 8.87 0.63 2.55 0.55 8.96 0.60 Table 2. Increase in selectivity of the sorbent (%) p-isomers on the o-isomers of the corresponding triads in all the modified samples of the sorbent Compounds Silikalite-1 + Cd2+ - Celite-545 Silikalite-2 + Cd2+ - Celite-545 Silikalite-1 + Tl+ - Celite-545 Silikalite-2 + Tl+ - Celite-545 Silikalite-1 + Ag+- Celite-545 Silikalite-2 + Ag+- Celite-545 p-xylene/ o-xylene 5.5 35 34.9 59 38.4 72 p-chlorotoluene/ o-chlorotoluene 29.3 39 37.4 194 38.8 236 p-dichlorobenzene/ o-dichlorobenzene 40.6 56 49.3 311 52.7 323 Table 3. Criterion (∆) of uniformity of the separation of a ternary model mixture of para-isomers on selective ad- sorbents (column temperature 230°C) Model mixture Initial (sodium) form of Silicalite-1 applied onto celite-545 Initial (sodium) form of Silicalite-2 applied onto celite-545 Cadmium form of Silikalite-1 applied onto celite-545 Cadmium form of Silikalite-2 applied onto celite-545 Thallium form of Silicalite-1 applied onto celite-545 Thallium form of Silicalite-2 applied onto celite-545 Silver form of Silikalite-1 applied onto celite-545 Silver form of Silikalite-2 applied onto celite-545 p-xylene– p-chloro- toluene– p-dichloro- benzene 0.24 0.27 0.37 0.40 0.44 0.47 0.56 0.58 Combining Molecular Sieve and Complexing Properties of the Column Packing _____________________________________________________________________________________________ ХФТП 2010. Т. 1. № 3 295 CONCLUSION After modification of corresponding stationary phases, the developed adsorbent can be successfully used in gas chromatography for the separation and analysis of mixtures of ortho-, meta-, and para- isomers of aromatic organic compounds. REFERENCES 1. Andronikashvili T.G., Tsitsishvili G.V. Chroma- tographic separation of low boiling inorganic and hydrocarbon gas mixtures on zeolites // J. Cromatogr. – 1984. – V. 292, N 1. – P. 3–8. 2. Tsitsishvili G.V., Andronikashvili T.G. Zeo- lites in Gas-Adsorptive Chromatography // Uspekhi khromatografii. – Moscow: Nauka, 1972. – P. 226–234 (in Russian). 3. McNair H.M., Bonelli E.J. Basic Gas Chro- matography. – Мoscow: Мir, 1970. – 277 p. (in Russian). 4. Andronikashvili T.G., Arustamova L.G., Sul- tanov N.T., Markaryan K.G, Liquid Crystals in Capillary Chromatography. – Tbilisi: Metsniereba, 1982. –98 p. (in Russian). 5. Tsitsishvili G.V., Andronikashvili T.G., Epri- kashvili L.G. Application of silicalite for the chromatographic separation xylene isomers // Dokl Akad. Nauk SSSR. – 1988. – V. 301, N 6, P 1401 (in Russian). 6. Andronikashvili T.G., Eprikashvili L.G., Pirts- khalava N.V., Witkhiewicz Z. Chromatographic separation of isomeric compounds of some benzene derivatives // Dokl. Akad. Nauk. – 1991. – V. 318, N 4. – P. 901 (in Russian). 7. Andronikashvili T.G., Eprikashvili L.G., Wit- khiewicz. Z. Chromatographic separation of isomers monofluorotoluene, monochlorotolu- ene and xylene // Chem. Anal. (Warsaw). – 1994. – V. 39. – P. 509. 8. Andronikashvili T.G., Eprikashvili L.G., Pirtskhalava N.V. et al. Gas chromatographic separation of isomeric benzene derivates us- ing molecular sieves combined with partition columns // Chromatographia. – 1994. – V. 38, N 9–10. – P. 613. 9. Dyer A. An Introduction to Zeolite Molecular Sieves. – New York: Wiley, 1988. – P. 20–21. 10. Barrer R.M. Hydrothermal Chemistry of Zeo- lites. – London: Academic, 1982. – 348 p. 11. Berezkin V.G. Chemical Methods in Gas Chromatography. – Moscow: Khimia, 1980. – 256 p. (in Russian). 12. Berezkin V.G., Gavrichev V.S., Kolomiets L.N. et al. Gas Chromatography in Petro- chemistry. – Moscow: Nauka, 1975. – 267 p. 13. Bombauch K. Improved Efficiency in Gas Chromatography by Molecular Sieve Flour // Nature. – 1963. – V. 197. – P. 1102. 14. Golbert K.A., Vigdergauz M.S. Introduction to Gas Chromatography. – Moscow: Khimiya, 1990. – 352 p. (in Russian). 15. Tsitsishvili G.V., Andronikashvili T.G. Inter- molecular interaction in gas chromatographic separation on zeolites // J. Chromatogr. A. – 1971. – V. 58, N 1. – P. 39–45. Received 18.05.2010, accepted 17.08.2010 Поєднання молекулярно-ситових і комплексоутворюючих властивостей насадок в газовій хроматографії Л. Епрікашвілі, Н. Пірцхалава, Т. Андронікашвілі, Т. Кордзахія, М. Зауташвілі, М. Дзаганія Інститут фізичної та органічної хімії ім. П. Мелікішвілі вул. Джикія 5, Тбілісі 0186, Грузія, physorgchem@pochta.ru Вивчено вплив модифікування синтетичних цеолітів сімейства пентасілів (Сілікаліту-1 і Сілікаліту-2) ка- тіонами металів, здатних до специфічних взаємодій, на розділювальну здатність хроматографічної колонки. Сочетание молекулярно-ситовых и комплексообразующих свойств насадок в газовой хроматографии Л.Эприкашвили, Н.Пирцхалава, Т.Андроникашвили, Т.Кордзахия, М.Зауташвили, М.Дзагания Институт физической и органической химии им. П. Меликишвили ул. Джикия 5, Тбилиси 0186, Грузия, physorgchem@pochta.ru Изучено влияние модифицирования синтетических цеолитов семейства пентасилов (Силикалита-1 и Силикалита-2) катионами металлов, способными к специфическим взаимодействиям, на разделительную способность хроматографической колонки.