Background of invention
Silica gel has special pore structure, and big specific surface area and good thermostability are widely used in each industrial circles such as sorbent material, siccative, thickening material, matting agent and support of the catalyst.In recent years, polythene material has become the national economy necessary part, and obtains swift and violent development, and poly production method has vapor phase process, slurry process and three kinds of production technique of solution method.Wherein Unipol polyolefin process route is because reduced investment, advantage such as flow process is short, working cost is low have occupied dominant position gradually in polyolefin industry for this, and the support of the catalyst of this technology is exactly the amorphous silica gel of modification.
Nowadays, in the vinyon (PE) of widespread use, high density polyethylene(HDPE) (HDPE) has been main in the world PE type, and the about high density polyethylene(HDPE) product 40% or more in the whole world is with phillips catalyst plant production, and this catalyzer by the silica gel load chromic salts after a year Ti activate and obtain.Since nineteen fifty-one, this catalyzer was found, research had determined that the pore structure of silica gel can influence whole catalytic process.Say that in principle the specific surface area that increases catalyzer can increase its reactive behavior, but single increase specific surface area is not enough, because silica gel also must have friability, because after polyreaction begins, polymkeric substance stops up pore immediately, catalyzer could continue to keep active after this moment, must break, otherwise polyreaction will be ended, so have only large pore volume silica gel just to have enough fragility, in polyreaction, can decompose fully, Here it is in recent years generally the pore structure of approval to the active influence of catalyst reaction, the size of the relative molecular mass that it can controlling polymers.
When traditional method prepared silica gel, specific surface was big, and pore volume is just little.Otherwise pore volume is big, and specific surface is again little, and the two is conflicting.Therefore must prepare the requirement of satisfying olefinic polyreaction with new method.
For this reason, each major company of the world researches and develops the new silica-gel carrier of manufacturing from different angles and field, make it have high specific surface area simultaneously, has big pore volume again, as: W.R.Grace, Phillips oil company, Davison chemical company, SCM chemical companies etc., ZL200410039492.1 has at large enumerated the various processing methodes of external production polyolefin catalyst carrier.
W.R.Grace.Co-conn company is one of major vendor of carrier for olefin polymerization catalyst produced in USA, discloses the manufacture method of two kinds of silica-gel carriers, and the first takes to reduce SiO
2Solubleness or the auxiliary agent of solvation, make SiO
2In the water-sol system of preparation, reduce SiO
2Solubleness and separate out into hydrogel, then through aging, washing, dry and roasting makes SiO
2Finished product, said auxiliary agent are ammonia, monohydroxy-alcohol, dibasic alcohol, ketone and salt.They can reduce the electric constant of separating in the water-sol system, thereby make SiO
2Separate out into gel, these auxiliary agents are evenly dispersed in and occupy certain space in the gel, washing, drying and roasting and be removed, and the silica-gel carrier specific surface area of production is 300~400m
2/ g, pore volume 1.2~2.8ml/g.
Disclosed other method is an azeotropic distn.The silicon gel that makes after the washing removal of impurities, is added C
5~C
6Alcohol, as the eleventh of the twelve Earthly Branches alcohol, hexanol or their mixture, remove water in the silicon gel by component distillation, obtain xerogel, 450 ℃~700 ℃ roastings make product, its physical index is: pore volume 2.0~2.5ml/g, specific surface area 420~550m
2/ g, bulk density 1.8~2.5g/ml.
Thereafter Grace company has improved azeotropic distn again.Mainly be to have selected some more suitably organic compound, as the compound of alcohol ether, pure ether-ether and so on.As oxyethyl group vinyl acetic monomer, tert.-butoxy propyl alcohol, Methoxy acetic acid propyl ester, the pure and mild ethoxyl ethyl propionate of n-butoxy etc.Carry out component distillation with these organic compound, to scheme to have improved the performance of carrier.
The Phillips oil company discloses many patents earlier, and azeotropic distillation technology has been discussed, and has selected boiling point than higher organic solvent, thinks C
5~C
6Alcohol be advisable, as 3 monomethyl butanols, positive the eleventh of the twelve Earthly Branches alcohol etc. have made the silica-gel carrier of large pore volume, high-specific surface area.
In addition, also studied freezing reaming method abroad, fused salt reaming method, supercritical drying etc.China has just begun to carry out the production domesticization research of polyolefine with silica-gel carrier as far back as the eighties, as of the development of Qingdao Haiyang chemical industry group to 955 silica gel, Sinopec institute, Tianjin chemical research institute and many universities etc., number of research projects has been done to the polyolefine silica-gel carrier by many units, and many articles and patent have been delivered, but the polyolefine silica-gel carrier of China still relies on import so far, the enterprise that the unique family of China produces polyethylene catalysts also is the silica-gel carrier raw material that depends on import, carries titanium and produces polyethylene catalysts.
The preparation method that high-specific surface area, the large pore volume of our company's invention carries chrome-silicon glue support of the catalyst has compared many innovations with the preparation method of home and overseas.The first is in gross porosity glue preparation, and we have increased the acidleach removal of impurities and add the urea auxiliary agent in wash water, helps removing and reaming of moisture in the silica gel hole; It two is the organic compound that carry out component distillation, and external that select is high boiling C
5Above alcohol or ester are C and we select
2~C
5Low boiling ester and alcohol, not only reduced boiling temperature, saved energy consumption widely, and reduced soltion viscosity, make the easier dispersion of silica gel product.The 3rd is that we have added high-molecular weight metal ester class or alkanes tensio-active agent in drying process, and it not only helps the modification of pore structure, has also eliminated interparticle static, has improved surface property.The 4th is that the external chromium acetate-toluene solution that adopts mostly carries chromium, and what we adopted is that chromium acetate-acetum or chromium acetate-ethanolic soln carry chromium.
Can then further specify the present invention by concrete enforcement:
Embodiment 1
With 20 ± 0.5% (wt) sodium silicate solution for preparing and 30 ± 0.5% (wt) sulphuric acid soln for preparing, by weight: the ratio of sodium silicate solution/sulphuric acid soln=5.555, squeeze in the mixing reactor with pump respectively, blend pressure is 0.36 ± 0.02mpa, the reaction mixture temperature is 30~40 ℃, mixed hydrogel is put into acidproof groove, under 35 ± 5 ℃ of temperature, leave standstill aging gelling after 40 hours, cut into the piece glue about 4cm, put into the wash water groove, wash, the hot water temperature is 50~60 ℃, wash the silica gel that obtains about PH7 and soaked 12 hours, use 40~50 ℃ of hot washes again, add 0.05% urea and soak and obtain refining silica gel after 4 hours to more than the PH6 with 3.5% Hcl; To make with extra care silica gel soaked 8 hours with the toluene solution that contains Cr 1.0% (wt), filter, to carry chrome-silicon glue again and put into the jacket reactor that band stirs, add positive butyl ester and carry out component distillation, after silica gel after the distillation carries out 100 ℃ of vacuum-dryings, the silane of adding 2% carries out modification to be handled, and then pulverizes with air classification and obtains D
50102 μ m, specific surface area 502m2/g (BET), year chrome-silicon glue carrier finished product of pore volume 2.5ml/g.
Embodiment 2
Except that following difference, all the other are identical with embodiment 1;
(1) HNO is adopted in acidleach
3, concentration 3.6%;
(2) concentration of adding urea is 1%;
(3) the Cr concentration of carrying chromium is 1.2% acetum;
(4) replace silane modifier with tetrabutyl titanate, add-on is 1.5%.
The index of carrying chrome-silicon glue carrier that obtains is: D
5094 μ m, specific surface area 490m
2/ g (BET), pore volume 2.38ml/g.
Embodiment 3
Except that following difference, all the other are identical with embodiment 1;
(1) acidleach Hcl 3.2%, HNO
33.2% mixing solutions;
(2) the Cr concentration of carrying chromium is 0.85% ethanolic soln;
The index of carrying chrome-silicon glue carrier that obtains is: D
50100.5 μ m, specific surface area 510m
2/ g (BET), pore volume 2.52ml/g.
Embodiment 4
Except that following difference, all the other are identical with embodiment 1;
(1) acidleach Hcl 3.0%+HNO
33.0% mixing solutions;
(2) the Cr concentration of carrying chromium is 0.95% butanol solution;
(3) organic compound of component distillation is the oxyethyl group vinyl acetic monomer;
The index of carrying chrome-silicon glue carrier that obtains is: D
5098 μ m, specific surface area 495m
2/ g (BET), pore volume 2.43ml/g.
Embodiment 5
Except that following difference, all the other are identical with embodiment 1;
(1) acidleach Hcl 3.0%+HNO
33.0% mixing solutions;
(2) the Cr concentration of carrying chromium is 1% isobutanol solution;
(3) organic compound of component distillation is an ethyl acetate;
The index of carrying chrome-silicon glue carrier that obtains is: D
5089 μ m, specific surface area 484m
2/ g (BET), pore volume 2.35ml/g.
Embodiment 6
Except that following difference, all the other are identical with embodiment 1;
(1) acidleach Hcl 3.5%+HNO
32.5% mixing solutions;
(2) the Cr concentration of carrying chromium is 1% propanol solution;
(3) organic compound of component distillation is an isopropylcarbinol;
The index of carrying chrome-silicon glue carrier that obtains is: D
5094 μ m, specific surface area 490m
2/ g (BET), pore volume 2.49ml/g.