Synthesis of polyols from carbon dioxide（CO2） is attractive from the viewpoint of sustainable development of polyurethane industry;it is also interesting to adjust the structure of the CO2-polyols for versatile requirement of polyurethane.However,when renewable malonic acid was used as a starter,the copolymerization reaction of CO2 and propylene oxide（PO） was uncontrollable,since it proceeded slowly（13 h） and produced 40.4 wt%of byproduct propylene carbonate（PC） with a low productivity of 0.34kg/g.A careful analysis disclosed that the acid value of the copolymerization medium was the key factor for controlling the copolymerization reaction.Therefore,a preactivation approach was developed to dramatically reduce the acid value to 0.6mg（KOH）/gby homopolymerization of PO into oligo-ether-diol under the initiation of malonic acid,which ensured the controllable copolymerization,where the copolymerization time could be shortened by 77%from 13 to 3 h,the PC content was reduced by 76%from 40.4 wt%to 9.4 wt%,and the productivity increased by 61%from 0.34 to 0.55 kg/g.Moreover,by means of preactivation approach,the molecular weight as well as the carbonate unit content in the CO2-diol was also controllable.
Shunjie LiuYusheng QinHongchen GuoXianhong WangFosong Wang
Herein, cisplatin-loaded poly(L-glutamic acid)-g-methoxy poly(ethylene glycol) nanoparticles were evaluated as a potential chemotherapeutic agent against osteosarcoma by using alone or with an i RGD(internalizing RGD, CRGDKDPDC). The release rate of platinum from the cisplatin-loaded nanoparticles CDDP/PLG160-g-m PEG2K(CDDP-NPs) accelerated with the increase of the acidity of the environment. In vitro test demonstrated that CDDP-NPs could inhibit the proliferation of MNNG/Hos osteosarcoma cells with IC50(72 h) of 12.2 μg?m L-1. In vivo test for MNNG/Hos osteosarcoma tumor bearing mice exhibited that CDDP-NPs had comparable or slightly higher efficacy but significantly lower side effects in comparison with free CDDP. The coadministration of i RGD could further enhance the anticancer efficacy of CDDP-NPs against MNNG/Hos osteosarcoma without bringing obvious side effects. Therefore, CDDP-NPs using alone or with i RGD have great potential for the treatment of osteosarcoma.
β-Imidophosphonamido ligated lutetium alkyl complex(NPNDipp)Lu(CH2Si Me3)2(THF)(NPNDipp = Ph2P(NC6H3iPr2-2,6)2) with the activation of AliBu3 and [Ph3C][B(C6F5)4] exhibited high catalytic activity, medium syndio-(rr = 66%) but remarkably high 3,4-regioselectivity for the polymerization of β-myrcene(MY). In sharp contrast, high isotactic 3,4-polymyrcene(PMY)(mm = 95%) was obtained by the precursor(NPNEt)Lu(CH2Si Me3)2(THF)(NPNEt = PPh2(NC6H3iPr2-2,6)(NC6H4-Et-2)) with less bulky substituents on the N-aryl ring.
