Molecular sieve chromatography

molecular sieve chromatography, also known as gel or gel filtration chromatography. Gel filtration is the use of a certain pore size range of porous gel as the stationary phase, the components of the mixture according to molecular size separating chromatographic technique. A substance having a 13x molecular sieves action are many, such as pumice, agar, agarose, polyvinyl alcohol, polyacrylamide, dextran gels and the like. Sephadex most widely trade name sephadex many models, from G10 to G200, its main applications are: ① fractionation various antigens and antibodies; ② remove complexes of small molecules. Such as desalination, fluorescein and free radioisotopes as well as protein hydrolysis fragments; ④ Determination of the molecular weight; ③ Analysis of immune complexes in serum.

Performance and structure of molecular sieve

Performance: zeolite powdery crystals with metallic luster, hardness of 3 to 5, the relative density of 2 to 2.8, color natural zeolite, synthetic zeolite powder obtained as a white, water-insoluble, heat stability and acid resistance as SiO2 / Al2O3 composition ratio increases and improved. molecular sieve molsiv have a great specific surface area, up to 300 ~ 1000m2 / g, the inner surface of the crystal highly polarized, as a class of highly efficient adsorbents, also a type of solid acid, the surface has a high acid concentration and acid strength, can cause carbonium catalytic ionic reactions. When the composition of the metal ions and other ions in solution were exchanged, adjustable aperture, changes its absorption properties and catalytic properties, which molecular sieve catalyst prepared with different properties.

The function of 4A molecular sieve properties

 Water softening ion exchange performance features: 4a molecular sieveframework are each oxygen atom is shared by two adjacent tetrahedra, this structure which may be occupied by cations and water molecules large bugholes, and these cations and water molecules have a greater mobility, cation exchange and reversible dehydration. 4A zeolite is ion exchange with aluminum ions in the framework carried a negative charge carried by each of the aluminum ions, may be not only sodium ions, may also be combined with other cations. Calcium and magnesium ions can enter the original sodium ions occupy a large crystal cave, the 4A Zeolite replace sodium ions 4A Zeolite down ---- that sodium ions can be exchanged with hard water Ca2 + ,, Mg2 + ions exchange, so as to achieve the purpose to soften water.
Combined with calcium and magnesium ions in zeolite 4a speed slower than sodium tripolyphosphate, and with the ability to bind magnesium ions is weak. But 4a molecular sieve can be a small amount of water in harmful heavy metal ions (such as Pb2 +, Cd2 +, Hg2 +) can be very easily and quickly removed to purify water has very important significance.
---- Carrier liquid of adsorptive functional surfactant: As 4a molecular sieve crystals of the hole structures, plus fine particles having a large specific surface area, so the strong adsorption performance of 4A molecular sieve.
Adsorption of non-ionic surfactants, 4A molecular sieves 3 times NTA (nitrilo-triacetate) and sodium carbonate, five times the sodium tripolyphosphate (STPP) and sodium sulfate, and the nature of the molding for the agglomeration production of high-concentrated detergent formulated with more surfactants, washing and flow properties obtained good product makes sense. Through the experiment, liquid Zeolite 4A carrying capacity ≥30%,4a molecular sieve in the detergent production process, increase the mobility of the material, to adjust the viscosity, obtained product appearance, sexual fluidity and anti-caking good product.
Detergency: experiments with different additives on the same formula, changing its detergency aid comparison, found 20% of the STPP, 20% of the molecular sieve, 4% polymer and 40% of the decontamination effect STPP rather, in 20% of non-phosphorus zeolite added 10% sodium carbonate and 4.5% of the polymer obtained very good detergency products.
Redeposition properties: 4a molecular sieve with good adhesion of oil, when sodium carbonate, CMC, sodium silicate and sodium and other additives added zeolite adsorption decreased nylon fabric for oil pollution. Particle size of the zeolite at 0.4-1.0μm, better dispersibility can be prevented from adhering on the fabric.
Although not as good as 4a molecular sieve dispersing ability STPP, but with sodium polyacrylate dispersion can solve complex problems of dirt.
Compatibility with other additives: 4A Zeolite proper performance and other additives can make it complementary, 4a molecular sieve dirt dispersion and hardness ions chelating inferior STPP, but 4A Zeolite mix with STPP, detergency can STPP reached with a single effect. This is because since the solid surface can quickly STPP complex calcium and magnesium ions, and passed through an aqueous medium 4A molecular sieves. 4A Zeolite magnesium ion binding ability, can be obtained by molecular sieve complex silicates, carbonates be compensated.
PH buffer: 4a molecular sieve alkaline PH 1% aqueous solution at 11.0, and therefore has a certain buffer alkalinity.
Safety: 4A Zeolite non-toxic, safe to human height. Eyes, skin irritation, does not cause allergies, safety and reliability. After washing deposited in the soil, does not cause pollution, but also can improve soil, 4A Zeolite no adverse impact on the ecology

functions and features of Molecular sieve

The porous material has been widely used in many fields, such as the main catalytic microporous molecular sieve material, adsorption and ion exchange material separation materials plays an increasingly important role in oil processing, petrochemicals, fine chemicals, and household chemicals .
molecular sieves(also known as a synthetic zeolite) is a microporous aluminosilicate crystalline silicon. It is made of silicon oxide, aluminum oxide tetrahedra basic skeleton structure, there is a metal cation in the crystal lattice (such as Na +, K +, Ca2 +, Li +, etc.), in order to balance the negative charge excess crystals. According to their type of zeolite crystal structure is divided into: A type, X-type, Y type.
Zeolite relevant standards:
"3a molecular sieve" "4A molecular sieve" "5a molecular sieve and test methods" "13X molecular sieve"
"Water assay method static sieve" "sieve dynamic water assay method"
"Granular sieve size determination," "Determination of bulk density of molecular sieve" "sieve crush strength test method", "Standard Test Method for molecular sieve desiccant cooling systems with anti-wear performance," "Determination of dynamic zeolite adsorption of carbon dioxide."
"Industrial activated alumina," "air separation plant with activated alumina acceptance technical conditions"

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 molecular sieves. Since the molecular sieve adsorbent 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 molecular sieve.
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 sieve 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

Performance and structure of molecular sieve

Performance: zeolite powdery crystals with metallic luster, hardness of 3 to 5, the relative density of 2 to 2.8, color natural zeolite, synthetic zeolite powder obtained as a white, water-insoluble, heat stability and acid resistance as SiO2 / Al2O3 composition ratio increases and improved. Molecular sieves have a great specific surface area, up to 300 ~ 1000m2 / g, the inner surface of the crystal highly polarized, as a class of highly efficient adsorbents, also a type of solid acid, the surface has a high acid concentration and acid strength, can cause carbonium catalytic ionic reactions. When the composition of the metal ions and other ions in solution were exchanged, adjustable aperture, changes its absorption properties and catalytic properties, which molecular sieve catalyst prepared with different properties.

Structure: proteoglycan thus formed polymer tortuous coiled, forming a sieve-like microporous structure, known as molecular sieves. Microporous molecular sieve which only allows material through is less than, greater than the pores of macromolecular substances, bacteria and the like having a barrier function is. The matrix becomes the limiting diffusion of harmful substances such as bacteria defensive barrier. Hemolytic streptococcus and cancer cells can produce hyaluronidase, the decomposition of proteoglycan, destruction of the matrix structure, to be spread. On binding proteoglycan aggregate also many hydrophilic groups, capable of binding water molecules, forming extracellular "reservoirs"

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 molecular sieve effect manufacturers for you to explain

5a zeolite powdere is a porous gel. Various molecular sieves have a range of pore size distribution, there is a maximum limit and minimum limit. The maximum pore diameter than the molecular diameter of the gel, will all be exclusion outside the gel particles, this situation is called a full-exclusion. Even if the full exclusion of two molecules of different sizes, can not have separation. Minimum pore diameter than the diameter of the gel small molecules can enter all pores of the gel. If two molecules can enter all the gel pores, even if their size difference, there will not be a good separation effect. Therefore, it must have a certain degree of molecular sieve range of use.
In summary, there are three cases in gel chromatography, one molecule is very small, can enter all of the zeolite 13x pores; the second is a large molecule, can not enter any of the gel pores; three molecules of moderate size , can enter within the pores of the gel pore size corresponding parts. Large, medium and small three molecules more readily separated from each other, but each gel isolated molecules outside the range, without changing the type of the gel is difficult to separate the cases. For molecules of different sizes, but the same is within the scope of the various gel isolated molecules, in the distribution of the gel bed is different: the larger molecules into the aperture only that part of the larger gel pores, and the molecule may enter more gel particles, such molecules larger movement distance is short, smaller molecules to move a long distance in the gel bed. So the larger molecules to smaller molecules through the gel bed and the rear through the gel bed, thus separating the molecular sieve can make use of different substances. Further, the gel itself has a three-dimensional network structure, when the large molecules through the pores in such a network structure on the greater resistance, resistance is small by small molecules. In adopting the gel bed, according to molecular size "queue, gels behave different molecular sieve effect size of various ingredients.