Process for producing polymerizable polybranched polyester
申请人:Hayakawa Hitoshi
公开号:US20060047140A1
公开(公告)日:2006-03-02
The present invention allows the production of a polymerizable hyperbranched polyester by introducing polymerizable unsaturated double bonds into the molecular terminals of a hyperbranched polyester polyol (A), which is obtained by condensation polymerization a polyhydroxy monocarboxylic acid in which there are at least two hydroxyl groups, the carbon atom adjacent to the carboxy group is saturated carbon atom, and the hydrogen atoms on said carbon atom are all substituted, by reacting the hyperbranched polyester polyol (A) and an alkyl ester of a carboxylic acid having a polymerizable unsaturated double bond (B) by a transesterification in the presence of at least one type of transesterification catalyst (C) selected from the group consisting of a dialkyl tin oxide and a stanoxane, without causing side reactions such as nucleophilic addition reactions of terminal hydroxyl groups to polymerizable unsaturated double bonds of the hyperbranched polyester polyol (A), or thermal polymerization of the polymerizable unsaturated double bonds. The polymerizable hyperbranched polyester can be produced at high efficiency using a transesterification that uses as an alkyl ester of a carboxylic acid having a polymerizable unsaturated double bond (B), which is easily obtained as an industrial raw material, and without altering the original backbone structure of the molecular chains of the hyperbranched polyester polyol (A) by hydrolysis and so forth.
PROCESS OF SEPARATING GASES USING POLYIMIDE MEMBRANES
申请人:Liu Chunqing
公开号:US20120323059A1
公开(公告)日:2012-12-20
The present invention discloses a new type of polyimide membrane with high permeances and high selectivities for gas separations and particularly for CO
2
/CH
4
and H
2
/CH
4
separations. The polyimide membranes have CO
2
permeability of 50 Barrers or higher and single-gas selectivity for CO
2
/CH
4
of 15 or higher at 50° C. under 791 kPa for CO
2
/CH
4
separation. The polyimide membranes have UV cross-linkable functional groups and can be used for the preparation of UV cross-linked polyimide membranes having CO
2
permeability of 20 Barrers or higher and single-gas selectivity for CO
2
/CH
4
of 35 or higher at 50° C. under 791 kPa for CO
2
/CH
4
separation.
The invention provides compounds adapted for the site-specific/sustained delivery of a centrally acting drug species to the brain having the formula [D-DHC] and the non- toxic pharmaceutically acceptable salts thereof, wherein [D] is a centrally acting drug species containing at least one reactive -OH, -COOH, -SH, -NH- or -NH2 functional group and [DHC] is the reduced, biooxidizable, blood-brain barrier penetrating lipoidal form of a dihydropyridine ⇒ pyridinium salt redox carrier comprising a dihydroquinoline or dihydroisoquinoline ring system, a carbon atom of the nitrogen-containing ring portion of said ring system being connected via a bridging group to a reactive -OH, -COOH, -SH, -NH- or -NH2 functional group in the centrally acting drug species. The corresponding quaternary derivatives are also described.
Aqueous parenteral solutions of drugs which are insoluble or only sparingly'soluble in water and/or which are unstable in water, combined with a hydroxypropyl,hydroxyethyl, glucosyl, maltosyl or maltotriosyl derivative of 3-or γ-cyclodextrin, provide a means for alleviating problems associated with drug precipitation at the injection site and/or in the lungs or other organs following parenteral administration.
Inclusion complexes of hydroxypropyl, hydroxyethyl, glucosyl, maltosyl or maltotriosyl derivatives of β- or γ-cyclodextrin with the reduced, biooxidizable, blood-brain barrier penetrating, lipoidal forms of dihydropyridine = pyridinium salt redox systems for brain-targeted drug delivery provide a means for stabilizing the redox systems, particularly against oxidation. The redox inclusion complexes also provide a means for decreasing initial drug concentrations in the lungs after administration of the systems, leading to decreased toxicity. In selected instances, complexation results in substantially improved water solubility of the redox systems as well.