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

Use of zeolites

Adsorbents and desiccants
Catalyst
Detergent
Other uses (wastewater treatment, soil conditioners, feed additives)
Zeolite is a new material, is widely used in industry, agriculture, defense and other sectors, and its use are continuing to explore. Zeolite is used as ion exchangers, adsorption separation, drying agents, catalysts, cement admixture. In the petroleum, chemical industry, as petroleum refining catalytic cracking, hydrocracking and petroleum chemical isomerization, reforming, alkylation, disproportionation; gas and liquid purification, separation and storage agent; water softening, water desalination agent; special desiccant (dry air, nitrogen, hydrocarbons, etc.). In light industry for the paper, synthetic rubber, plastics, resins, fillers and coating quality color. In defense, space technology, ultra-high vacuum technology, the development of energy, electronics, etc., used as a separating agent and desiccant adsorption. In the building materials industry, as active hydraulic cement admixture, firing artificial lightweight aggregate, produce lightweight high-strength sheet metal and bricks. In agriculture as a soil conditioner, can play a fertilizer, water, prevent pest effect. In the livestock industry, as feed (pigs, chickens) additives and deodorants, can promote animal growth, improve chick survival. In terms of environmental protection to deal with waste gas, waste water, removal or recycling of metal ions, removal of radioactive contaminants in wastewater effluent from the wastewater.
activated zeolite powders in medicine for the determination of blood and urinary nitrogen content. Zeolite was also developed as a health supplies for anti-aging, remove heavy metals accumulated in the body.
In the production of zeolite commonly used in sugar refining.
New wall materials (aerated concrete blocks) materials
With the solid clay brick gradually leave the stage, the proportion of new wall materials application has now reached 80% of the wall materials production enterprises to gangue, fly ash, ceramic, slag, light industrial waste, heavy construction waste and zeolite based materials, and actively develop new wall materials.
Distillation or heating in a chemical experiment which used to prevent bumping, because the structure of the synthetic zeolite powder which have a large number of small holes, can be used as the bubble condensation nuclei, the reaction solution stable boiling. Available crack to the grain size of unglazed tiles instead.

Introduction and development of carbon molecular sieve background

Description: carbon molecular sieveis a novel sorbent developed in the 1970s, and is an excellent material non-polar carbon, nitrogen carbon molecular sieve(Carbon Molecular Sieves, CMS) for the separation of air enriched in nitrogen, room temperature using low-pressure nitrogen process than conventional high-pressure nitrogen cryogenic process has less investment costs, faster production of nitrogen, nitrogen, and low cost. Therefore, it is currently the preferred engineering PSA (the PSA) nitrogen-enriched air separation adsorbents, such as nitrogen in the chemical industry, oil and gas industry, electronic industry, food industry, coal industry, the pharmaceutical industry, the cable industry, metal heat treatment, transportation and storage and other aspects of a wide range of applications.

R & D background: the 1950s, along with the tide of the industrial revolution, more and more widespread application of carbon materials, including activated carbon applications
PSA nitrogen with carbon molecular sieve
PSA nitrogen with carbon molecular sieve
Extended fastest filter impurities from the initial separation of the progressive development of the different components. At the same time, as technology advances, the human processing capacity of the material is also growing, in this case, carbon molecular sieve adsorbentinto being

What is zeolite desiccant.

Aluminosilicate compound having a cubic lattice, is mainly composed of silicon aluminum attached through an oxygen bridge consisting of the open framework structure, there are a lot of uniform pore size and neat in pore structure, large surface area of the inner hole. It also contains a low price and a larger ionic radius of metal ions and the chemical form of water. Since the water molecules in the continuous loss of heat, but the same crystal framework structure, the formation of many of the same size of the cavity, the cavity there are many of the same diameter connected pores, the diameter of these small pores of uniform size, pore ratio can diameter smaller molecules adsorbed into the interior of the cavity in the past, and the ratio of pores too large molecular exclusion, and thus able to molecular diameter different shapes, different degree of polarity of the molecule, the boiling point of different molecules, the different degree of saturation of molecular separation open, that has the effect of "screening" elements, so called molecular sieves. Currently #zeolite #desiccant widely used in the metallurgical, chemical, electronics, petrochemical and natural gas industries.

Introduction and development of carbon molecular sieve background

Description: carbon molecular sieveis a novel sorbent developed in the 1970s, and is an excellent material non-polar carbon, nitrogen carbon molecular sieve(Carbon Molecular Sieves, CMS) for the separation of air enriched in nitrogen, room temperature using low-pressure nitrogen process than conventional high-pressure nitrogen cryogenic process has less investment costs, faster production of nitrogen, nitrogen, and low cost. Therefore, it is currently the preferred engineering PSA (the PSA) nitrogen-enriched air separation adsorbents, such as nitrogen in the chemical industry, oil and gas industry, electronic industry, food industry, coal industry, the pharmaceutical industry, the cable industry, metal heat treatment, transportation and storage and other aspects of a wide range of applications.

R & D background: the 1950s, along with the tide of the industrial revolution, more and more widespread application of carbon materials, including activated carbon applications
PSA nitrogen with carbon molecular sieve
PSA nitrogen with carbon molecular sieve
Extended fastest filter impurities from the initial separation of the progressive development of the different components. At the same time, as technology advances, the human processing capacity of the material is also growing, in this case, carbon molecular sieve adsorbentinto being

Characteristics of zeolite

Zeolite is zeolite family of minerals in general, is an aqueous alkali metal or alkaline earth metal aluminum silicate mineral. By zeolite mineral characteristics into frame, sheets, fibers and Unclassified of four, according to pore system characteristics into one-, two-, three-dimensional system. Any zeolite by silicon-oxygen tetrahedron and aluminum oxygen tetrahedra. Tetrahedron can only apexes, i.e. sharing one oxygen atom, and not "side" or "face" is connected. Aluminum-oxygen tetrahedron itself can not be connected, there have been at least one silicon-oxygen tetrahedron. The silicon-oxygen tetrahedron can be directly connected. Silicon-oxygen tetrahedron silicon, aluminum atoms can be replaced by aluminum-oxygen tetrahedron constituted. However, aluminum atoms are trivalent, so aluminum tetrahedron, there is an oxygen atom price has not been neutralized, a charge imbalance is generated, so that the whole is negatively charged tetrahedral aluminum oxide. In order to maintain a neutral, positively charged ions must be offset to compensate for the generally alkali metal and alkaline earth metal ions, such as Na, Ca and Sr, Ba, K, Mg and other metal ions. Because zeolite has a unique internal structure and chemical properties of crystallization, thus making the 5a zeolite powderhas a variety of industrial and agricultural use of the available features.
The world has discovered natural zeolite is generally light gray, sometimes red meat. In our hands, obviously felt lighter than stone, which is fine because the interior is filled with zeolite cavities and channels, much more complex than the hive. If the zeolite compared to hotels, so within a cubic micron of this "super hotel" as much as one million "room"! These rooms can be based on "Passenger" (molecules and ions) sex, height, fat, thin, different automatic door or onto trains, hobby, will not let the "Fat Man" to "thin" the room to go, does not make tall Shorty and sharing a room. According to the characteristics of zeolite molecular screening of people use it to get good results. This has particular significance for the recovery of copper, lead, cadmium, nickel, molybdenum and other metal particles in industrial waste.
Zeolite having adsorption, ion-exchange, acid catalysis and heat resistance properties, it is widely used as adsorbents, ion exchangers and catalysts, may also be used for drying gases, purification and sewage treatment and so on. Zeolite also has a "nutritional" value. 5% of the synthetic zeolite powders in the feed, make livestock grow faster, Tizhuang fresh meat, egg production rate.
Due to the nature of the porous silicate zeolite, the wells there is a certain amount of air, is often used riot boiling. When heated, the air inside the hole escape, acts as a gasification nuclei, small bubbles are easily formed on the corners.

Principle of carbon molecular sieve nitrogen air separation

The product is carbon molecular sieve adsorbent is a porous material composed of carbon, pore structure model for disordered accumulation of carbon. Carbon molecular sieves non-stoichiometric compounds, important properties which is based on its cellular structure. It is the ability to separate the air, depending on a variety of gases in the air, carbon molecular sieve pore diffusion different speeds or different adsorption, or both effects simultaneously. Under equilibrium conditions, the carbon molecular sieve adsorption of oxygen and nitrogen is very close, but oxygen molecules through the diffusion rate of nitrogen molecules faster narrow voids than molecular sieve olecular sieve systems, carbon molecular sieve nitrogen air separation is based on this performance, before the time far from equilibrium conditions, the separation by the PSA process so that the nitrogen gas from the air
Third, the device is generally referred to as nitrogen machine. Which process is the use of pressure swing adsorption method at room temperature (referred to as PSA), PSA for pyrogen adsorption separation process, carbon molecular sieve is adsorbed component (mainly oxygen molecules) absorption capacity due to the above principle in the charge pressure, when the gas adsorption, the exhaust gas desorption during depressurization, regeneration carbon molecular sieve. At the same time, the bed gas phase enriched nitrogen gas through the bed a product, each step even for loop operations.
PSA process cycle operations include: pressurized gas production; grading; buck, exhaust; then pressurized gas production; ...... several working stages, the formation of cyclic operation. Depending on the method of its regeneration process can be divided into vacuum regeneration regeneration processes and atmospheric processes.
PSA Nitrogen device according to the user's needs may include compressed air purification systems, pressure swing adsorption systems, process control systems valves (vacuum regeneration with a vacuum pump needed), and nitrogen supply system

Market analysis of carbon molecular sieve

For a long time, carbon molecular sieve as Japan and Germany, monopoly product, before 2000 was 80% of the domestic share of their possession, especially on the international market. Carbon molecular sieve technology through the introduction of domestic Changxing chemical, carbon molecular sieve domestic manufacturers are mainly distributed in Changxing, Shandong, Xuancheng, and other places. Since 2000, the city declared Sun to new materials and other companies on behalf of some of the major manufacturers through continuous improvement and innovation, performance, made of carbon molecular sieve has been considerable development, in addition to the price advantage as a result of domestic products, domestic sieve gradually seize most of the market share, but to become bigger and stronger in this industry, we must innovation, improve product performance, breaking the technical barriers to trade. [2]
The next few years, carbon 5a molecular sieves product will be high index, high strength, high bulk density direction, low index products will be eliminated low-level, ASU will tend to miniaturization, molecular sieve industry has put forward higher requirements, So as to seize the current favorable opportunity to expand production, gradually changing international and domestic Chinese-made carbon molecular sieves for cheap low-quality knowledge to quickly seize the domestic and international market, it will be possible within two to three years to become the industry pacesetter.

Domestic market
In 2012, the domestic market mainly middle and low carbon molecular sieve, the total demand of 6,000 tons, as China's economy continues to develop, chemical industry, especially the expanding scale, the level of demand for carbon molecular sieve will gradually increase, especially in recent years, the state of coal, oil, attaches great importance to the security of oil tankers, forcing oil tanker with a nitrogen generator, electronics and material needs of industry, further expanding domestic demand for carbon molecular sieves. According to the survey, since 2000, the annual average growth rate of more than 80% of the domestic market prospects.

International market
As technology continues to mature PSA, Nitrogen applications increasingly broad demand for carbon molecular sieve is also growing international demand in Europe and America and other developed countries are growing steadily each year in recent years, the development of demand in the country is leaps and bounds, with an annual growth rate doubled, a conservative estimate, the total demand of the international carbon molecular sieves at several hundred thousand tons more than in 2013

Carbon molecular sieve works

Use of carbon molecular sieves are sieved to achieve the separation characteristics of oxygen, nitrogen purpose. When molecular sieve adsorption of impurity gases, mesopores and macropores function as channels only, the adsorbed molecules transported to the sub-micropores and the micropores, the volume of micropores and sub-micropores is that really Adsorption. As shown below, the carbon molecular sieves comprise a large number of internal pores, the pores allow the kinetics of small molecules rapidly diffuse into the hole size, while limiting the entry of large diameter molecules. Due to the different sizes of the gas molecules relative diffusion rate differences, components of the gas mixture can be effectively separated. Thus, in the manufacture of carbon molecular sieves, molecular sieve oxysiv according to the size of the carbon molecular sieve in the internal pore distribution should be 0.28 ~ 0.38nm. Within this pore size range, the oxygen can quickly diffuse into the hole through the porous openings, and the nitrogen is difficult through the porous opening, so as to achieve an oxygen, nitrogen separation. Microporous carbon molecular sieve pore size is the separation of oxygen, nitrogen base, if the pore size is too large, oxygen, nitrogen, into the pores of the molecular sieve is easy, but there is no separation of the role; pore size is too small, oxygen, nitrogen can not enter micropores, but there is no separation.
Domestic molecular sieve due to conditions imposed on the pore size control is not very good. Market sales of carbon molecular sieve pore size distribution of 0.3 ~ 1nm, only Iwatani zeolite did 0.28 ~ 0.36nm. Carbon molecular sieve material for coconut shell, coal, resins, etc., the first step after processing powder, then blend with the base material, the base material is to increase strength and prevent fragmentation pulverized material; second step is to create activation hole, at a temperature of 600 ~ 1000 ℃ passed through activator, commonly used activator water vapor, carbon dioxide, oxygen and a mixture thereof. They are more lively and amorphous carbon thermal chemical reaction to form holes and gradually expand the surface area activated pore time ranging from 10 ~ 60min; The third step is to adjust the pore structure, the use of chemical vapors: such as benzene in carbon microporous molecular sieve wall deposition to adjust the size of the holes, so as to satisfy the requirements.

Knowledge of the structure and characteristics of zeolite molecular sieves collection

Molecular sieve is a silicate or a crystalline aluminosilicate, and formed of silicon oxide or aluminum oxide tetrahedra linked by oxygen bridges tetrahedron. Molecular size (typically 0.3 ~ 2.0 nm) of the pore and cavity system, so as to have characteristics of solid molecules. However, with the synthesis and application of molecular sieve-depth study, researchers found that the aluminophosphate molecular sieves and sieve skeleton elements (silicon or aluminum or phosphorus) may be composed of B, Ga, Fe, Cr, Ge, Ti, V , Mn, Co, Zn, Be and Cu, substituted, its pore size and the cavity may reach 2 nm or more, the zeolite framework elements can be divided according to type aluminosilicate zeolite, aluminophosphate molecular sieves and molecular sieve framework heteroatoms ; divided by pore size, pore size of less than 2 nm, 2 ~ 50 nm and the molecular sieve is larger than 50 nm are referred to as micropores, mesopores and large pore molecular sieves. Because of the larger aperture size becomes larger carrier molecules react well, but the pore walls of mesoporous materials are amorphous, resulting in the hydrothermal stability and thermal stability still can not meet the required conditions for petrochemical applications demanding .
molecular sieve molsiv sieves contain a lower price due to the larger ionic radius and water, the #water #molecules are continuously lost after heating and combined state of the metal ion, but the same crystal framework structure, the formation of many of the same size of the cavity, the cavity there are many the same diameter of pores connected to these tiny hole diameter uniform pores smaller than molecules can adsorb to the internal diameter of the cavity in the past, but larger than the pores of the molecular exclusion, which can diameter molecules of different shapes Different degrees of polar molecules, the boiling point of different molecules, different degrees of saturation molecules separated, that has the effect of "screening" elements, so called molecular sieves. Currently zeolite 5a widely used in the metallurgical, chemical, electronics, petrochemical and natural gas industries.

There are two kinds of synthetic zeolite molecular sieve zeolite and natural. Most ① natural zeolite formed by volcanic tuffs occur and tuffaceous sedimentary rocks in marine or lacustrine environment reaction. Has 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 most natural zeolite molecular sieves mined large country. ② due to natural zeolite subject to resource constraints, from the beginning of the 1950s, a large number of synthetic zeolites (see Table).

Goods zeolite crystal structure common prefixes Digital classify the different molecular sieves, such as type 3A, 4A type, 5A zeolite. 4A Class A type that table, aperture 4 & Aring ;. A type containing Na + sieve recorded as Na-A, if one Na + is K + replacement, pore size of about 3 & Aring ;, is the 3A molecular sieve; as Na-A has more than 1/3 of Na + was Ca2 + exchange, aperture is about 5 & ​​Aring ;, is the 5A molecular sieve.