The Structure And Properties Of Novel Hypercrosslinked Resins Synthesised By Simple Aromatic Molecules

Hypercrosslinked resins, as a kind of adsorption-separation materials developed very fast in recent years based on their excellent properties such as the fine pore structure, high BET surface areas, high mechanical strength, good adsorption selectivity and good desorption-regeneration properties. Now, hypercrosslinked resins are widely used in many fields such as the treatment of wastewater and the extracting of natural products. However, the structure of most hypercrosslinked resins are single St-DVB skeleton, and their preparing cost is also very high. With the enlargement of their application field, develop new method of synthesising hypercrosslinked resins tun out to be very important.(1) Hypercrosslinked resin XDC-BA and CMB-BA were prepared with p-xylylene dichloride(XDC),4,4’-dichloromethyl biphenyl(CMB) and benzyl alcohol(BA), their chemical structure and micromorphology were characterized by IR, elemental analysis and BET methods. The results showed that the specific surface area of resin XDC-BA and CMB-BA were up to1200.05m2/g and1028.03m2/g respectively, and the average pore diameter of resin XDC-BA and CMB-BA were1.925nm and1.918nm.(2) XDC and CMB are expensive. So, a series of new hypercrosslinked resins were synthesized by a facile method using simple aromatic molecules such as benzene, xylene, toluene, naphthaline and chloromethyl methyl ether(CME) as starting materials. These resins were obtained by chloromethylation reaction of aromatic molecules with CME and post-crosslinking of Friedel-Crafts reactions without separation. These resins were also characterized by elemental analyses, fourier infrared spectra (FT-IR). The results shows that, the reaction was inadequate, and there are still a lot of unreacted chloromethyl group remained on the resins. To further improve the surface area of some resins, a crosslinking process was adopted. After crosslinked, the surface areas of the resins were increased significantly by20%-368%respectively. The steric hindrance of aromatic molecules and the molar ratio of aromatic molecules to CME have great effects on the crosslinking degree of the resins. The rosult shows that resins synthesized by this method exhibit Brunauer Emmett Teller(BET) surface areas from41.31to974.38m2/g, and the average pore diameter of the resins were mostly micropore ranging from1.117nm and1.925nm.Contrasted with nonpolar resins, polar resins such as oxygen-containing resins have higher adsorption capacity to some polar adsorbate. Traditionally, polar resins were obtained by chemical modified, this methodologies contain its disadvantages such as higher production cost, fussy synthetic processes and low oxygen content. Among our research, two kinds of high oxygen-containing resins BA-CME and PH-CME were prepared by using benzyl alcohol or phenetole and CME. The oxygen content of BA-CME and PH-CME were up to6.50%and11.91%respectively. The specific surface area of resin BA-CME and PH-CME were up to525.00m2/g and352.45m2/g, and the average pore diameter were1.123nm and1.699nm respectively. The method has the advantages of simple synthetic procedure, low cost and high oxygen content.(3) Thinking of chloromethyl methyl ether (CME) is a carcinogenic substance,1,4-bis(chloromethoxyl)butane was synthesized with formaldehyde, PCl3and1,4-butanediol. After that, two kinds of novel hypercrosslinked resins N-BC and BA-BC were synthesised with1,4-bis(chloromethoxyl)butane, naphthalene and benzylalcohol. The micromorphology of the resins were characterized with BET, in addition, IR spectra and elemental analysis of the resins were also characterized. The results indicated that, the novel adsorption resins possess high specific surface area (501.04m2/g and288.28m2/g) and abundant micropore structure (average pore diameter1.128nm and1.121nm). Compared with CME, the properties of1,4-Bis(chloromethoxyl)butane is low toxicity and little pollution to environment. A new process for preparing hypercrosslinked resins was described.(4) Based on the synthesis of the resins, the adsorption isotherms of resin BA-CME, PH-CME, BE-CME, P-BE-CME and XAD-4for phenol and aniline were measured in aqueous solutions, the adsorption capacity of all the resins for phenol and aniline were about2times as high as that of XAD-4under the same experimental conditions. Equilibrium data for the adsorptions of phenol and aniline from aqueous solutions had been obtained. The results indicated that, the specific surface area, oxygen content and the average pore diameter of the resins seemed to be the main factor affecting the adsorption quantity. The resins can be applied in the treatment of waste water with phenol and aniline.