Principles and types of Zeolite

Absorption features: molecular sieve adsorption material from physical adsorption (van der Waals forces), which has a strong internal crystal cavities polarity and Coulomb field of polar molecules (such as water) and unsaturated molecules show a strong adsorption capacity.
Screening function: very uniform pore size distribution of the molecular sieve, only molecular diameter smaller than the diameter of the hole before substance may enter bughole internal molecular sieves.
By order of priority and size to distinguish molecular adsorption of different substances, so the image is called "molecular sieve."
Type: synthetic zeolite molecular sieve zeolite and two natural. Most ① natural zeolite formed by volcanic tuffs occur and tuffaceous sedimentary rocks in marine or lacustrine environment reaction. Have been found to have more than 1000 kinds of zeolite mineral, the more important ones are 35 kinds, often with clinoptilolite, mordenite, erionite and chabazite, etc. Mainly in the United States, Japan, France and other countries, China also found that a large number of mordenite and clinoptilolite deposits, Japan is the largest country in the natural zeolite mined. ② due to natural zeolite subject to resource constraints, from the beginning of the 1950s, a large number of synthetic zeolites.
Goods zeolite crystal structure common prefixes Digital classify the different molecular sieves, such as type 3A, 4A type, 5a zeolite molecular sieves. 4A Class A type that table, aperture 4Å ;. A type of zeolite containing Na +, referred to as Na-A, if one is Na + K + replacement, pore size of about 3Å ;, is the 3A molecular sieve; Na-A if there is more than one third of the Na + Ca2 + exchange, aperture is about 5Å ;, is the 5A molecular sieve.

Principles and types of Zeolite

Absorption features: molecular sieve adsorption material from physical adsorption (van der Waals forces), which has a strong internal crystal cavities polarity and Coulomb field of polar molecules (such as water) and unsaturated molecules show a strong adsorption capacity.
Screening function: very uniform pore size distribution of the molecular sieve, only molecular diameter smaller than the diameter of the hole before substance may enter bughole internal molecular sieves.
By order of priority and size to distinguish molecular adsorption of different substances, so the image is called "molecular sieve."
Type: synthetic zeolite molecular sieve zeolite and two natural. Most ① natural zeolite formed by volcanic tuffs occur and tuffaceous sedimentary rocks in marine or lacustrine environment reaction. Have been found to have more than 1000 kinds of zeolite mineral, the more important ones are 35 kinds, often with clinoptilolite, mordenite, erionite and chabazite, etc. Mainly in the United States, Japan, France and other countries, China also found that a large number of mordenite and clinoptilolite deposits, Japan is the largest country in the natural zeolite mined. ② due to natural zeolite subject to resource constraints, from the beginning of the 1950s, a large number of synthetic zeolites.
Goods zeolite crystal structure common prefixes Digital classify the different molecular sieves, such as type 3A, 4A type, 5a zeolite molecular sieves. 4A Class A type that table, aperture 4Å ;. A type of zeolite containing Na +, referred to as Na-A, if one is Na + K + replacement, pore size of about 3Å ;, is the 3A molecular sieve; Na-A if there is more than one third of the Na + Ca2 + exchange, aperture is about 5Å ;, is the 5A molecular sieve.

Some catalytic behavior of molecular sieve dehydration in ethanol amination reaction

Aliphatic amines is an important raw material of pesticides, pharmaceuticals, dyes and other industries. Its main synthetic methods ammoniated alcohol dehydration and alcohol dehydrogenation amination, an AI:. O, as a catalyst since production has since been put in since the early 1960s. Its alcohol conversion rate is acceptable, but a less selective amine. Binary and ternary metal oxide catalytic systems studied many reports ['', due to poor performance, the industry .zSM a selective 5 zeolite came after an attempt to take advantage of its role in improving the shape-selective primary amine has not been adopted Research work has been reported ['a 6'. Selective dehydration of methanol amination reaction of methylamine is indeed improved. For alcohol-containing C-C bond, 3a zeolite molecular sieves dehydration amination reaction catalyst as a research work has not yet commenced. This article focuses on the study of various zeolite acidity, pore structure on ethanol dehydration amination. Got some interesting results. Experiment 1 reagent and preparing zeolite powder original NaY (Wenzhou Chemical), NaM (Nanjing plant 5a zeolite molecular sieves  and NaZSM a 5 (Nankai Chemical) were treated with 10% NH; NO. Solution, 1 mol / L and 0.1 mol L hydrochloric acid solution / Maid change at a certain temperature for several hours to obtain sodium hydrogen zeolite washing, suction filtration, drying, take part NaHY, NaHM, NaHzSM a 5 respectively 5% LaC13, La 10% MgclZ solution obtained corresponding exchange, Mg · zeolite, washing, suction filtration, dried and set aside. Pu 2 test zeolite catalyst

Zeolite drying technology

Conventional molecular sieve drying technique commonly used hot air natural gas dryingtechnology, and microwave drying technology to solve the traditional dry sieve drying slow, energy loss, poor product quality problems, in particular in: 1, microwave drying fast molecular sieve, generally a few minutes 2 can achieve the purpose of microwave drying, microwave drying sieve evenly to achieve the depth of dry, good product quality; 3, still dry, do not burn with less dust; 4, microwave drying molecular sieve process safety, energy conservation, environmental protection and the use of electricity, dry inside and outside at the same time, electric drying than saving more than 50%; 5, shorten the production cycle, greatly reducing the production of working capital; 6, microwave drying equipment cabinet temperature below 40 ℃, improve workers' working environment.

Introduction of Zeolite

molecular sieve is a cubic lattice of an aluminosilicate compound having. Molecular sieve has a uniform porous structure, the diameter of its pores of uniform size, these cavities can adsorb molecules smaller diameter than the internal bore, and an unsaturated polar molecules and molecules having a preferential adsorption capacity, and thus able to very different degree, different degree of saturation, and boiling points of different molecular sizes of different molecules separated, that has the effect of "screening" elements, so called zeochem molecular sieves  Since the molecular sieves have a high adsorption capacity, high thermal stability other adsorbents that are not so widely applied molecular sieve.
In the field of biological macromolecules, a common bio-rad SEC sieve prepacked columns.
US scientists have found that by adjusting the temperature, to precisely control one titanium silicate material pore size, to create a sophisticated molecular sieve. Some internal crystal material has a large number of uniform pore size smaller than the molecules can pass through the holes, while large molecules can not pass through, and thus serves to separate different molecules, such materials are known as air separate unit molecular sieve adsorbent.
In fact, in 2001, scientists in the UK "Nature" magazine reported that they had discovered a titanium silicate material known as ETS-4 can be used as a good molecular sieve. When the temperature rises, ETS-4 will gradually dehydrated, pore size decreases. Finely adjust the pore size in the use of this method, (1 angstrom equals one billion of a meter) in the 3-4 Angstroms range. Scientists say some common elements such as nitrogen, methane, oxygen, argon and water molecules are about the size of 3-4 Å, another is almost the same size, molecular sieves drying made with ETS-4 can effectively separate them. Researchers have experimented with ETS-4 from the nitrogen content in the mixture of nitrogen and methane, from 18% to 5%, and in the separation of argon and oxygen, nitrogen and oxygen experiments have been successful. It is believed that this technology will have important commercial applications