Showing papers on "Transfer agent published in 2001"
TL;DR: In this paper, the authors studied the effect of the length of the chain length on the polymerization behavior in cross-linking free radical polymerizations and showed that chain length dependent termination is present in free radical free radical polymers.
49 citations
TL;DR: Comparison of experimental results to calculation results indicates that the CH2I-I photoproduct species is most likely the methylene transfer agent for the cyclopropanation reaction of olefins via ultraviolet photoexcitation of diiodomethane.
Abstract: We examine the chemical reactions of the isodiiodomethane (CH2I-I), .CH2I and CH2I(+) species with ethylene using density functional theory computations. The CH2I-I species readily reacts with ethylene to give the cyclopropane product and an I2 product via a one-step reaction with a barrier height of approximately 2.9 kcal/mol. However, the.CH2I and CH2I(+) species have much more difficult pathways (with larger potential barriers) to react with ethylene via a two-step reaction mechanism. Comparison of experimental results to our present calculation results indicates that the CH2I-I photoproduct species is most likely the methylene transfer agent for the cyclopropanation reaction of olefins via ultraviolet photoexcitation of diiodomethane.
47 citations
Patent•
25 Oct 2001
TL;DR: In this article, the authors presented a method of producing copolymer copolymers by placing a vinylbenzene such as styrene in a reactor, placing a cross-linking agent, such as divinylbenzenes in the reactor, and placing a chain transfer agent such as mercaptan, in the reactors.
Abstract: The present invention provides a method of producing a copolymer. The method comprises placing a vinylbenzene, such as styrene, in a reactor, placing a cross-linking agent, such as divinylbenzene in the reactor, placing a chain transfer agent, such as mercaptan, in the reactor and forming a poly vinylbenzene in the presence of the cross-linking agent and the chain transfer agent. In this embodiment, the concentration of the cross-linking agent ranges from about 150 ppm to about 400 ppm and a concentration of the chain transfer agent ranges from about 100 to about 400 ppm.
21 citations
TL;DR: In this article, the authors showed that a star poly(acrylic acid) could not be synthesized via telomerization of acrylic acid in an organic medium (THF) at 65°C.
Abstract: The telomerization of acrylic acid with a polyfunctional transfer agent initiated by 2,2′-azobisisobutyronitrile, was first investigated in an organic medium (THF) at 65 °C. Transfer constants (CT) for three mercaptans, ethylene glycol bisthioglycolate, trimethylolpropane tris(2-mercaptoacetate) and pentaerythritol tetrakis(3-mercaptopropionate) of about 6.1, 6.3 and 7.3, respectively, were determined. From these results, it followed that a well-defined star poly(acrylic acid) could not be synthesized via telomerization of acrylic acid in THF. Nevertheless, the same study was performed with the tetrafunctional transfer agent in water/THF mixtures. This work emphasized that the nature of the solvent plays an important role in determining the transfer constant. Thus, the value of CT for the tetrafunctional transfer agent decreased from 7.3 in THF to 1, the ‘ideal’ case for telomerization (CT ≈ 1), for the mixture of solvents water/THF (80%, 20%, v/v). With this route, it seems that acrylic acid star-shaped macromolecules could be synthesized via telomerization.
© 2001 Society of Chemical Industry
20 citations
Patent•
14 Nov 2001
TL;DR: In this paper, an emulsion composition for therapeutic administration consisting of at least one mono-electron transfer agent (ME) and at least di-electric transfer agent phosphate derivative was provided.
Abstract: There is provided an emulsion composition for therapeutic administration comprising: (a) at least one mono-(electron transfer agent) phosphate derivative; (b) at least one di-electron transfer agent phosphate derivative; wherein the amount of transfer agent phosphate derivatives is no less than equimolar to the amount of di-electron transfer agent phosphate; and (c) a suitable carrier.
20 citations
TL;DR: In this paper, a highly efficient method for labeling with deuterium was described using an acidic hydrocarbon as transfer agent, using 9-[ 2 H ]-9-phenylfluorene as the de-uterium donor, numerous organic compounds were labeled in fair yields and good isotopic enrichment.
13 citations
Patent•
20 Apr 2001
TL;DR: In this article, a photo-polymerizable resin composition consisting of a polymerizable component containing at least one addition polymerizable compound having an ethylenically unsaturated bond was proposed.
Abstract: PROBLEM TO BE SOLVED: To obtain a photo-polymerizable resin composition having a high sensitivity especially to ultraviolet light or visible light, capable of being cured with a picture-drawing laser and also excellent in preservation stability after a membrane formation on a base substrate and after the picture-drawing. SOLUTION: This photo-polymerizable resin composition consists of (A) a polymerizable component containing at least one addition-polymerizable compound having an ethylenically unsaturated bond, (B) a photo-polymerization initiator, (C) a chain transfer agent, (D) a thermal polymerization inhibitor, and (E) tetrazole or its derivative, or triazole or its derivative, and preferably contains 0.5-10 mass % photo-polymerization initiator (B), 0.2-5 mass % chain transfer agent (C), 0.01-0.1 mass % thermal polymerization inhibitor (D) and 0.01-0.5 mass % tetrazole or its derivative, or triazole or its derivative (E). COPYRIGHT: (C)2002,JPO
7 citations
Patent•
14 Mar 2001
TL;DR: In this article, the problem of providing a polymer having a functional group at one terminal of a cycloolefinic polymer by subjecting it to metathetical polymerization was addressed.
Abstract: PROBLEM TO BE SOLVED: To provide a polymer having a functional group at one terminal of a cycloolefinic polymer by subjecting a cycloolefinic monomer to metathetical polymerization in the presence of a chain transfer agent having a functional group, and a block copolymer by the copolymerization with MMA or styrene with the use of the polymer. SOLUTION: The cycloolefinic polymer is produced by metathetical polymerization and has a functional group to be represented by the formula: CH2 =CH- Z1 -Q1 or CH2 =CH-Z2 -(Q2 ) (Q3 ) which is derived from a chain transfer agent at one terminal alone. The block copolymer using the polymer and its manufacturing method are also described.
7 citations
TL;DR: In this paper, the free radical polymerization of styrene and methyl methacrylate leads to ester and sulfide-containing polymers functionalized both in chain ends as well as in the chains.
Abstract: Chain transfer to ethylene bis(mercaptoacetate) in the free radical polymerisation of styrene and methyl methacrylate leads to ester and sulfide-containing polymers functionalized both in chain ends as well as in the chains. The functionalized polystyrene can be (bio)degraded from ester functions as well as from sulfide functions. Attempts to chemically degrade functionalized poly(methyl methacrylate) from sulphur functions was less successful.
5 citations
Patent•
19 Oct 2001
TL;DR: In this paper, the authors proposed a method for the production of methacrylic resins with narrow molecular weight distribution and free from discoloration in melt-molding process.
Abstract: PROBLEM TO BE SOLVED: To provide a methacrylic resin having narrow molecular weight distribution and free from discoloration in melt-molding process. SOLUTION: The methacrylic resin is produced by carrying out the radical copolymerization of a raw material containing an acrylic acid ester and a methacrylic acid ester in the presence of a RAFT (reversible addition- fragmentation chain transfer) agent which is a kind of a chain transfer agent and optionally decoloring the product with an oxidizing agent or a nucleophilic reagent. The invention further provides a method for the production of the resin.
4 citations
Patent•
07 Dec 2001TL;DR: An acidizing composition and a method of acidizing a hydrocarbon bearing subterranean formation in the presence of ferric ions are provided in this paper, where an electron donor agent and primary and secondary electron transfer agents function together to reduce ferric ion present in the mineral acid solution to ferrous ion which in turn prevents ferric hydroxide and free sulfur from precipitating out of the solution and reduces the formation of sludge in crude oil in the formation.
Abstract: An acidizing composition and a method of acidizing a hydrocarbon bearing subterranean formation in the presence of ferric ions are provided The acidizing composition includes a mineral acid solution, an electron donor agent, a primary electron transfer agent and a secondary electron transfer agent The primary electron transfer agent is a source of vanadium ions The secondary electron transfer agent is a source of iodide ion or iodine The electron donor agent and primary and secondary electron transfer agents function together to reduce ferric ion present in the mineral acid solution to ferrous ion which in turn prevents ferric hydroxide and/or free sulfur from precipitating out of the solution and reduces the formation of sludge in crude oil in the formation
TL;DR: In this article, the anomalous popcorn formation in the presence of a large amount of lauryl mercaptan as a chain transfer agent was explored in the free-radical cross-linking copolymerization of benzyl methacrylate with neopentyl glycol dimethACrylate.
Patent•
04 May 2001TL;DR: In this article, higher-alkane sulfonyl halides are prepared by contacting a sulfur-containing compound, a halogen containing compound, and a phase transfer agent within a reaction zone under reaction conditions.
Abstract: Higher-alkane sulfonyl halides are prepared by contacting a sulfur-containing compound, a halogen-containing compound, and a phase transfer agent within a reaction zone under reaction conditions.
Patent•
21 Mar 2001
TL;DR: In this paper, a method for manufacturing a fluorine-containing copolymer, whose melt viscosity is suitable for a molding material and whose molecular weight distribution is well controlled to assure the dimensional consistency of molded products, is presented.
Abstract: PROBLEM TO BE SOLVED: To provide a method for manufacturing a fluorine-containing copolymer, whose melt viscosity is suitable for a molding material and whose molecular weight distribution is well controlled to assure the dimensional consistency of molded products, by enabling the solution copolymerization of tetrafluoroethylene and a fluorine-containing vinyl ether in the presence of a hydrofluorocarbon-based inactive solvent and a chain transfer agent. SOLUTION: A fluorine-containing copolymer is manufactured by a method wherein tetrafluoroethylene and a fluorine-containing vinyl ether, described by the formula: CF2=CFOCH2(CF2)nX, wherein X is a hydrogen atom or a halogen atom and n is an integer of 1 or larger, are allowed to react upon each other in a copolymerization reaction for the manufacture of a fluorine- containing copolymer, with CF3CHFCHFCF2CF3 acting as reaction solvent in the presence of a chain transfer agent occupying 0.5-4 mol percent of the whole amount of monomers injected. It is preferred that copolymerization will proceed at a reaction temperature of 15-35 deg.C.