Synthesis, structure, and optical activity of HPM-1, a pure silica chiral zeolite

Alex Rojas, Oriol Arteaga, Bart Kahr, Miguel A. Camblor

Research output: Contribution to journalArticle

Abstract

2-Ethyl-1,3,4-trimethylimidazolium is a poor organic structure-directing agent in the synthesis of pure silica zeolites using fluoride as a mineralizer at 150 C. Under these conditions only ill-crystallized solids are obtained after long hydrothermal treatments (several weeks). It disappoints despite its relatively large size, conformational rigidity, and intermediate hydrophilic/hydrophobic character, attributes which would qualify it as a promising structure-directing agent, according to prior investigations. By raising the crystallization temperature to 175 C under otherwise identical conditions, crystallization is dramatically accelerated. Depending on the water/silica ratio and crystallization time, two different materials are obtained: the recently reported pure silica polymorph of the chiral STW-type zeolite, HPM-1, and the new layered organosilicate, HPM-2. Prolonged heating transforms these phases into the small-pore ITW-type zeolite, while no signs of the SOF-type zeolite (formally built from the same layers as STW) was found. A complete physicochemical and structural characterization of the as-made chiral HPM-1 zeolite is provided, and the proposed stabilization of this zeolite by polarization of the Si-O bond is supported by the observed deviation from tetrahedrality. HPM-1 is optically active, and a study of several crystallites by Mueller matrix microscopy shows that their optical activity can be individually measured and that this technique could be useful for the assessment of the enantiomeric purity of a microcrystalline powder.

Original languageEnglish (US)
Pages (from-to)11975-11984
Number of pages10
JournalJournal of the American Chemical Society
Volume135
Issue number32
DOIs
StatePublished - Aug 14 2013

Fingerprint

Optical Rotation
Zeolites
Silicon Dioxide
Crystallization
Silica
Polymorphism
Crystallites
Rigidity
Microscopic examination
Stabilization
Polarization
Heating
Powders
Fluorides
Water
Microscopy
Temperature

ASJC Scopus subject areas

  • Chemistry(all)
  • Catalysis
  • Biochemistry
  • Colloid and Surface Chemistry

Cite this

Synthesis, structure, and optical activity of HPM-1, a pure silica chiral zeolite. / Rojas, Alex; Arteaga, Oriol; Kahr, Bart; Camblor, Miguel A.

In: Journal of the American Chemical Society, Vol. 135, No. 32, 14.08.2013, p. 11975-11984.

Research output: Contribution to journalArticle

Rojas, Alex ; Arteaga, Oriol ; Kahr, Bart ; Camblor, Miguel A. / Synthesis, structure, and optical activity of HPM-1, a pure silica chiral zeolite. In: Journal of the American Chemical Society. 2013 ; Vol. 135, No. 32. pp. 11975-11984.
@article{8a9539dfd7444f7189c19f430639af95,
title = "Synthesis, structure, and optical activity of HPM-1, a pure silica chiral zeolite",
abstract = "2-Ethyl-1,3,4-trimethylimidazolium is a poor organic structure-directing agent in the synthesis of pure silica zeolites using fluoride as a mineralizer at 150 C. Under these conditions only ill-crystallized solids are obtained after long hydrothermal treatments (several weeks). It disappoints despite its relatively large size, conformational rigidity, and intermediate hydrophilic/hydrophobic character, attributes which would qualify it as a promising structure-directing agent, according to prior investigations. By raising the crystallization temperature to 175 C under otherwise identical conditions, crystallization is dramatically accelerated. Depending on the water/silica ratio and crystallization time, two different materials are obtained: the recently reported pure silica polymorph of the chiral STW-type zeolite, HPM-1, and the new layered organosilicate, HPM-2. Prolonged heating transforms these phases into the small-pore ITW-type zeolite, while no signs of the SOF-type zeolite (formally built from the same layers as STW) was found. A complete physicochemical and structural characterization of the as-made chiral HPM-1 zeolite is provided, and the proposed stabilization of this zeolite by polarization of the Si-O bond is supported by the observed deviation from tetrahedrality. HPM-1 is optically active, and a study of several crystallites by Mueller matrix microscopy shows that their optical activity can be individually measured and that this technique could be useful for the assessment of the enantiomeric purity of a microcrystalline powder.",
author = "Alex Rojas and Oriol Arteaga and Bart Kahr and Camblor, {Miguel A.}",
year = "2013",
month = "8",
day = "14",
doi = "10.1021/ja405088c",
language = "English (US)",
volume = "135",
pages = "11975--11984",
journal = "Journal of the American Chemical Society",
issn = "0002-7863",
publisher = "American Chemical Society",
number = "32",

}

TY - JOUR

T1 - Synthesis, structure, and optical activity of HPM-1, a pure silica chiral zeolite

AU - Rojas, Alex

AU - Arteaga, Oriol

AU - Kahr, Bart

AU - Camblor, Miguel A.

PY - 2013/8/14

Y1 - 2013/8/14

N2 - 2-Ethyl-1,3,4-trimethylimidazolium is a poor organic structure-directing agent in the synthesis of pure silica zeolites using fluoride as a mineralizer at 150 C. Under these conditions only ill-crystallized solids are obtained after long hydrothermal treatments (several weeks). It disappoints despite its relatively large size, conformational rigidity, and intermediate hydrophilic/hydrophobic character, attributes which would qualify it as a promising structure-directing agent, according to prior investigations. By raising the crystallization temperature to 175 C under otherwise identical conditions, crystallization is dramatically accelerated. Depending on the water/silica ratio and crystallization time, two different materials are obtained: the recently reported pure silica polymorph of the chiral STW-type zeolite, HPM-1, and the new layered organosilicate, HPM-2. Prolonged heating transforms these phases into the small-pore ITW-type zeolite, while no signs of the SOF-type zeolite (formally built from the same layers as STW) was found. A complete physicochemical and structural characterization of the as-made chiral HPM-1 zeolite is provided, and the proposed stabilization of this zeolite by polarization of the Si-O bond is supported by the observed deviation from tetrahedrality. HPM-1 is optically active, and a study of several crystallites by Mueller matrix microscopy shows that their optical activity can be individually measured and that this technique could be useful for the assessment of the enantiomeric purity of a microcrystalline powder.

AB - 2-Ethyl-1,3,4-trimethylimidazolium is a poor organic structure-directing agent in the synthesis of pure silica zeolites using fluoride as a mineralizer at 150 C. Under these conditions only ill-crystallized solids are obtained after long hydrothermal treatments (several weeks). It disappoints despite its relatively large size, conformational rigidity, and intermediate hydrophilic/hydrophobic character, attributes which would qualify it as a promising structure-directing agent, according to prior investigations. By raising the crystallization temperature to 175 C under otherwise identical conditions, crystallization is dramatically accelerated. Depending on the water/silica ratio and crystallization time, two different materials are obtained: the recently reported pure silica polymorph of the chiral STW-type zeolite, HPM-1, and the new layered organosilicate, HPM-2. Prolonged heating transforms these phases into the small-pore ITW-type zeolite, while no signs of the SOF-type zeolite (formally built from the same layers as STW) was found. A complete physicochemical and structural characterization of the as-made chiral HPM-1 zeolite is provided, and the proposed stabilization of this zeolite by polarization of the Si-O bond is supported by the observed deviation from tetrahedrality. HPM-1 is optically active, and a study of several crystallites by Mueller matrix microscopy shows that their optical activity can be individually measured and that this technique could be useful for the assessment of the enantiomeric purity of a microcrystalline powder.

UR - http://www.scopus.com/inward/record.url?scp=84882256289&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84882256289&partnerID=8YFLogxK

U2 - 10.1021/ja405088c

DO - 10.1021/ja405088c

M3 - Article

VL - 135

SP - 11975

EP - 11984

JO - Journal of the American Chemical Society

JF - Journal of the American Chemical Society

SN - 0002-7863

IS - 32

ER -