| Organic non-ionic Superbases have received great attention due to their high catalytic efficiency in modern organic transformations. Proazaphosphatranes, also known as Verkade Base, is a kind of strong non-ionic phosphorus-bases with its characteristic structure. After a series of process, Polymer-supported Verkade Base was obtained. The Polymer-Supported Verkade Base has good catalytic activity in the esterification. The main content of this article is as follows:PSt-DVB, a great kind of catalyst carrier, is produced by suspension polymerization. Through investigation, the optimized reaction condition is as follows: stiring speed, 200 rpm; D.I. water, 50 g; m(St), 10.0 gram; the weight ratio of DVB, 10% of St; dispersant, 1.0%; initiator, 1.6%; porogenic, 20%. And polystyrene-divinyl benzene resin microspheres with appropriate particle size and better morphology was obtained.1,4-bis-chloromethoxybutane(BCMB) is a kind of long chain chlorine methyl alkyl ether with high boiling point and low toxicity. Using BCMB as the chlorine methylation reagent avoids the potential harm. The appropriate reactive condition is: 1,4-butane-diol, 9.0 gram; paraformaldehyde, 6.5gram; HCl, 75 mL; H2SO4,100 mL; reactive time, 5 h; reactive temperature, 22℃; Calcium Chloride, 7.0 gram; benzene, 15 mL. The total yield of this reaction is 76%.The chlorine methylation of PSt-DVB and BCMB catalysted by anhydrous Zinc Chloride/anhydrous Stannic Chloride was introduced. The appropriate reactive condition is: PSt-DVB(crosslinking dedree is 4%): 1.5 gram; BCMB: 6.00 gram; CH2Cl2: 15 mL; reactive temperature: 45℃; swelling time: 4 h; reactive time: 12 h. The chloride content was determined with Fajans method. The chloride content is 17%(wt%) when the crosslinking is 4%. Resin-N3 was obtain after reaction between 1 gram Chloromethylate PSt-DVB and 0.4 gram sodium azide.Tris(2-aminoethyl)amine(tren) was obtained via Gabriel method with yields of 65.4%. Then tren was reacted with ethyl chloroformate and through reduction of LiAlH4, tris(N-methyl-2-aminoethyl)amine was obtained with total yields of 74.8%. After that, tris(N-methyl-2-aminoethyl)amine was reacted with PCl3, HEPT and potassium tert-butoxide to give 2,8,9-trimethyl-2,5,8,9-tetraaza-1-phosohorus bicyclo[3.3.3] hendecane called Verkade Base. Immobilization of Verkade Base was synthetized after the reaction between Verkade Base and Resin-N3, with 1 mmol Verkade Base contented in every gram carrier.Polymer-supported catalyst was applied in the reaction of esterification. The substates are methyl benzoate, butyl benzoate, ethyl salicylate, dibutyl phthalate and ethyl acrylate. The esterification reaction of substrates and alcohol under the catalyst of polymer-supported catalyst was introduced. The method of tracing the process of esterification is thin-layer chromatography. The molecular structure was confirmed by 1H NMR and other testing methods. The experimental results demonstrate that the polymer-supported catalyst possess good catalytic effect. |
