制备了带有1,2-苯二醇或1,2,3-三羟基苯单元的多酚型表面活性剂,并将其用作Ga 3+的浮选捕收剂。表面活性剂在pH 11(32–47 dyn cm –1)时表面张力降低。在等摩尔C n – 1 H 2 n – 1 C下,镓(III)在pH 3–8时高度漂浮(80–90%)。(O)C 6 H 3(OH)2(n = 8或12)或C 7 H 15 C(O)C 6 H 2(OH)3,但与C 12 H 25 S相比不那么高(60%)[CH2 CHC(O)C 6 H ^ 3(OH) 2 ] 4.8(CH 2 CHCO 2 2H) 9.5 H.镓的可浮3+在1mol分米-3的NaOH分别为86-99%,在那些3摩尔分米-通过使用六倍摩尔过量的C n – 1 H 2 n – 1 C(O)C 6 H 3(OH), 3 NaOH的含量为63–67%,在5 mol dm –3 NaOH中的含量为26–39%。)
In the presence of boron trifluoride diethyl etherate (BF3·OEt2), direct acylation of phenols with free carboxylic acid is chemoselective and regioselective and no demethylation, if any, was observed. The para-directing effect of BF3·OEt2 is attributed to the large steric hindrance of the boron trifluoride-phenolic hydroxyl group complex, which blocks the ortho-acylation from occurrence. Microwave irradiation could not change the regioselectivity of BF3·OEt2 except the reaction time being greatly shortened.
Soluble late transition metal catalysts for olefin oligomerizations III
申请人:Zhao Baiyi
公开号:US20060036049A1
公开(公告)日:2006-02-16
A series of soluble α-diimine late transition metal catalysts has been invented comprising a substituted or unsubstituted catecholate ligand. The catalysts demonstrate high activity and selectivity for linear α-olefins. As such, these catalysts conveniently oligomerize ethylene. Typical activators as known to those of ordinary skill in the art are used to activate these transition metal catalysts. These catalysts can be used in a supported or unsupported form.