Takashi Kondo

Sorption of nitrogen oxides on MnOy–ZrO2 and Pt-ZrO2–Al2O3

Abstract Manganese zirconium oxide (MnO y –ZrO 2 ) and platinum–zirconium oxide supported on Al 2 O 3 (Pt-ZrO 2 –Al 2 O 3 ) were investigated as effective and reversible sorbents for NO x . The sorption is initiated by oxidation of NO on a Mn or Pt surface. Then, the oxidized NO x species are stored as nitrate ions on ZrO 2 . These sorbents exhibited rapid and large sorption of NO in the presence of gaseous O 2 . Coexisting CO 2 in the atmosphere hardly affected the sorption and desorption properties. The sorbed NO x species desorbed on heating or on exposure to a reducing atmosphere. The evolved gas was quite dependent on the active catalytic component, such as Pt or Mn. Selective catalytic reduction of NO x or decomposition of NO easily proceeded on Pt during desorption in the reducing atmosphere. In this case, the desorption gas contained a large proportion of N 2 or N 2 O species for Pt-ZrO 2 –Al 2 O 3 . But the desorbed gas from MnO y –ZrO 2 contained mainly NO and NO 2 , whereas the NO desorption was dominant in the reducing atmosphere. The difference in desorption species is suggested to result from the existence of the active lattice oxygen on Mn oxide.

Resolution of aliphatic alcohols by hydrogen bond “double hooks” of cholanamide inclusion compounds

Abstract Resolution of aliphatic alcohols by an inclusion method with cholanamide (3α, 7α, 12α-trihydroxy-5β-cholan-24-amide) is studied.

A novel molecular channel with a hydrogen bond ‘hook’; inclusion phenomena of cholanamide and the crystal structure of a 1:1 complex of cholanamide and 1,4-dioxane

A new host, Cholanamide (CAM), is described; CAM forms lattice inclusion compounds with a variety of organic substances, particularly hydrogen bond acceptors, which are trapped in channels by hydrogen bonding to the amide nitrogen.

Structures of three inclusion compounds of cholanamide with either (S)-enantiomer, (R)-enantiomer or an optically resolved mixture of butan-2-ol

The three types of inclusion compounds of cholanamide (CAM, 3α, 7α, 12α-trihydroxy-5β-cholan-24-amide) have been crystallized from the solutions of (S)-butan-2-ol (CAMSB), (R)-butan-2-ol (CAMRB) and racemic butan-2-ol (CAMSRB), respectively. The crystal structures have been determined. The three crystal structures are isomorphous to each other and revealed that the host CAM molecules form the same layered arrangements, providing channel spaces for the guest butan-2-ol molecules. As expected, the CAMSB and CAMRB crystals include the pure (S)- and (R)-enantiomers of butan-2-ol, whereas the (S)-enriched mixture of enantiomers is accommodated in CAMSRB with a molar ratio between the host CAM and guest butan-2-ol molecules of 1:1. The hydrogen-bond network is rigidly formed between the CAM molecules and also between CAM and butan-2-ol molecules. CAMSB and CAMRB have slightly different unit-cell dimensions: the channels in CAMRB have a larger section, resulting in a larger unit-cell volume. In CAMSRB, although both enantiomers of the guest alcohol are included, the (S)-enantiomer is more abundant, indicating that the optical resolution occurs during the crystallization step.

Channel-type inclusion crystal with hydrogen bond ‘hooks’ of deoxycholanamide

Abstract Deoxycholanamide forms lattice inclusion compounds with a variety of organic substances; the 1:1 inclusion crystal of the amide with 1-butanol has a bilayer structure involving channels with hydrogen bond hooks for the guests.