Stereopopulation control. VII. Rate enhancement in the lactonization of 3-(o-hydroxyphenyl)propionic acids: dependence on the size of aromatic ring substituents
Process for the preparation of halogenated (meth)acrylic esters and poly (meth) arcylates obtained with said (meth)acrylic esters
申请人:Akzo Nobel N.V.
公开号:EP0824096A2
公开(公告)日:1998-02-18
The present invention is directed to a process for the preparation of (meth)acrylates of halogenated alcohols by direct esterification of said alcohols with (meth)acrylic acid (chloride) wherein at least 2,6-substituted pyridine derivative is used as a polymerization inhibitor at room temperature or lower. Suitable at least 2,6-substituted pyridine derivatives are 2,6-lutidine, 2,4,6-collidine or 2,6-di-tert.butyl-4-methyl pyridine.
With the halogenated (meth)acrylate esters prepared with the process according to the invention, very pure homo- and copolymers can be prepared, resulting in polymers having a low optical loss of 0.1 dB/cm or lower at 1300 nm and lower than 0.4 dB/cm at 1550 nm.
Chemical consequences of fluorine substitution. Part 4. Diels–Alder reactions of fluorinated p-benzoquinones with Dane's diene. Synthesis of fluorinated D-homosteroids
作者:Michael Essers、Günter Haufe
DOI:10.1039/b208001j
日期:——
depends on the fluorine substitution pattern of the corresponding fluorinated p-benzoquinones. If the p-benzoquinone (2) contains an unfluorinated double bond, this bond reacts faster with diene 1 yielding endo-products selectively. In contrast, [4+2]cycloadditions with 2,6-difluoro (2c) and 2,3,5,6-tetrafluorobenzoquinone (2d) gave the products with exo-orientation of the carbonyl part preferably.
Ethylened polymer and molded object obtained therefrom
申请人:Satoh Yasuo
公开号:US20060135712A1
公开(公告)日:2006-06-22
An ethylene-based polymer which is an ethylene/C4 to C10 α-olefin copolymer and satisfies the following requirements [k1] to [k3]: [k1] melt flow rate (MFR) under a loading of 2.16 kg at 190° C. is in the range of 1.0 to 50 g/10 minutes; [k2] LNR defined as a scale of neck-in upon film molding is in the range of 0.6 to 1.4; and [k3] take-up speed at break [DS (m/min)] at 160° C. and melt flow rate (MFR) satisfy the following relationship (Eq-1): 12×MFR
0.577
≦DS≦165×MFR
0.577
(Eq-1), and a thermoplastic resin composition containing the ethylene-based polymer, provide a molded product, preferably a film, excellent in moldability and mechanical strength. The ethylene-based polymer can be efficiently obtained by polymerization in the presence of an olefin polymerization catalyst formed from a solid carrier, (A) a solid transition metal catalyst component obtained by contacting (a) a compound of a transition metal of the group 4 in the periodic table, containing at least one ligand having a cyclopentadienyl skeleton, (b) an organoaluminum oxy compound, (c) a multifunctional organic halide, and if necessary (d) an organoaluminum compound, and if necessary (B) organoaluminum compound.