A mild and efficient two-step synthesis of a polystyrene thiol resin is reported. Firstly, a polystyrene resin was reacted with an activated sulfoxide to afford the resin bound bis-(2-methoxy-carbonylethyl)-sulfonium trifluoromethanesulfonate. Smooth β-elimination based dealkylations afforded the polystyrene thiol resin with good and controlled loading. Its reactivity was assessed through a derivatisation step. 相似文献
A chitosan resin functionalized with 3-nitro-4-amino benzoic acid moiety (CCTS-NABA resin) was newly synthesized for the collection/concentration of trace molybdenum by using cross-linked chitosan (CCTS) as base material. The carboxyl group of the moiety was chemically attached to amino group of cross-linked chitosan through amide bond formation. The adsorption behavior of molybdenum as well as other 60 elements on the resin was examined by passing the sample solutions through a mini-column packed with the resin. After the elution of the elements collected on the resin with 1 M HNO3, the eluates were analyzed by inductively coupled plasma-mass spectrometry (ICP-MS) and atomic emission spectrometry (ICP-AES).
The CCTS-NABA resin can adsorb several metal ions, such as vanadium, gallium, arsenic, selenium, silver, bismuth, thorium, tungsten, tin, tellurium, copper, and molybdenum at appropriate pHs. Among these metal ions, only molybdenum could be adsorbed almost completely on the resin at acidic regions. An excellent selectivity toward molybdenum could be obtained at pH 3–4. The adsorption capacity of CCTS-NABA resin for Mo(VI) was 380 mg g−1 resin. Through the column pretreatment, alkali and alkaline earth metals in river water and seawater samples were successfully removed.
The CCTS-NABA resin was applied to the adsorption/collection of molybdenum in river water and seawater samples. The concentrations of molybdenum in river water samples were found in the range of 0.84 and 0.95 ppb (ng g−1), whereas molybdenum in seawater was about 9 ppb. The validation of the proposed method was carried out by determining molybdenum in the certified reference materials of SLRS-4, CASS-4, and NASS-5 after passing through the CCTS-NABA resin; the results showed good agreement with the certified values. 相似文献
By using a combination of a chiral N‐triflyl phosphoramide and TiCl4 as the catalyst, a new process for asymmetric intramolecular hydroalkoxylation of unactivated alkenes was developed, producing various chiral tetrahydrofuran derivatives in 51%—99% yields with 30%—71% ee's. 相似文献