Boron-containing molecular sieve cha

Abstract

A boron-containing molecular sieve having the CHA crystal structure and comprising (1) silicon oxide and (2) boron oxide or a combination of boron oxide and aluminum oxide, iron oxide, titanium oxide, gallium oxide and mixtures thereof is prepared using a quaternary ammonium cation derived from 1-adamantamine, 3-quinuclidinol or 2-exo-aminonorbornane as structure directing agent. The molecular sieve can be used for gas separation or in catalysts to prepare methylamine or dimethylamine, to convert oxygenates (e.g., methanol) to light olefins, or for the reduction of oxides of nitrogen n a gas stream (e.g., automotive exhaust) and to reduce cold start emissions from engines.

Description

Background of the invention [0001] The crystal structure of chabazite known as "CHA" is an approximate molecular formula of Ca 6 al 12 Si 24 o 72 natural zeolite. Synthetic forms of chabazite are described by D. W. Breck in Zeolite Molecular Sieves, John Wiley & Sons, 1973. The various synthetic forms reported by Breck are: zeolite "K-G" described by Barrer et al. in J.Chem.Soc., p.2822 (1956); zeolite D disclosed in BP 868846 (1961) and April 17, 1962 Zeolite R disclosed in US 3030181 to Milton et al. Chabazite is also discussed in W.H. Meier and D.H. Olson, "Atlas of Zeolite Structure Types" (1978). [0002] The K-G zeolite reported by Barrer et al. in J. Chem. Soc. is a potassium zeolite having a silica:alumina molar ratio (referred to herein as "SAR") of 2.3:1 to 4.15:1. Zeolite D reported in BP868846 is a sodium-potassium zeolite with a SAR of 4.5:1 to 4.9:1. Zeolite R reported in US3030181 is a sodium zeolite with a SAR of 3.45:1 to 3.65:1. [0003] Abstract ent...

AI Technical Summary

Problems solved by technology

However, it does not disclose boron-containing CHA zeolites

Images