摘要:
Butadiene polymers are brominated using tetraethylammonium tribromide as the brominating agent. The bromination is performed in a solvent for the starting polymer and for the tetraethylammonium bromide that is formed as a reaction byproduct. The process proceeds easily under mild conditions. In some cases, a solution of the brominated polymer and the tetraethylammonium monobromide is produced; this solution separates into a layer that contains the brominated polymer and another layer that contains most or all of the tetraethylammonium monobromide salt. In other cases, the brominated polymer precipitates from the reaction mixture and is separated from the tetraethylammonium monobromide salt in that manner. This process therefore permits the tetraethylammonium monobromide reaction by-product to be separated easily from the brominated product, and allows aqueous washing steps to be reduced or eliminated.
摘要:
Butadiene copolymers are brominated in solution using bromine as the brominating agent. The bromination is conducted in the presence of an excess of an aliphatic alcohol, relative to the amount of bromine that is used. The bromination proceeds rapidly at mild conditions, and is selective in that only aliphatic carbon-carbon double bonds are brominated, and unwanted bromination at tertiary carbon atoms is largely or completely avoided. The resulting brominated polymers are characterized in having very good thermal stability.
摘要:
Butadiene copolymers are brominated using certain quaternary ammonium tribromides as the brominating agent. The bromination process proceeds easily under mild conditions, and produces a brominated product that has excellent thermal stability.
摘要:
Butadiene copolymers are brominated using certain quaternary ammonium tribromides as the brominating agent. The bromination process proceeds easily under mild conditions, and produces a brominated product that has excellent thermal stability.
摘要:
Butadiene copolymers are brominated in solution using bromine as the brominating agent. The bromination is conducted in the presence of an excess of an aliphatic alcohol, relative to the amount of bromine that is used. The bromination proceeds rapidly at mild conditions, and is selective in that only aliphatic carbon-carbon double bonds are brominated, and unwanted bromination at tertiary carbon atoms is largely or completely avoided. The resulting brominated polymers are characterized in having very good thermal stability.
摘要:
Unsaturated organic compounds are brominated with a quaternary ammonium tribromide or a quaternary phosphonium tribromide, especially when the bromination is conducted in a chlorinated solvent. A quaternary ammonium or quaternary phosphonium monobromide salt is produced in the reaction, together with some amount of quaternary ammonium or quaternary phosphonium monochloride salt. The monochloride salt is converted to the corresponding quaternary ammonium monobromide salt by reacting it with a source of bromide ions. The monobromide salt is then reacted with bromine to regenerate the quaternary ammonium or phosphonium tribromide, which is recycled into the bromination reaction. This process reduces the amount of chlorine that is incorporated into the brominated product.
摘要:
Detecting attempted intrusions in a telecommunications signaling network and assessing the vulnerability of the network to attempted intrusions. Intrusion rules are applied to received messages in the network in real-time, using a known protocol for the network, in order to detect anomalies tending to indicate an attempted intrusion. In order to assess the vulnerability of the network, vulnerability rules are applied to rankings of particular parameters relating to elements in the network. The rankings provide an indication of susceptibility of a network element to an attempted intrusion relative to other network elements.
摘要:
Butadiene copolymers are brominated using certain quaternary ammonium or phosphonium tribromides as the brominating agent. The bromination is performed in solution in a mixture of n-butyl acetate and ethyl acetate. The bromination process proceeds easily under mild conditions, and produces a brominated product that has excellent thermal stability.
摘要:
Butadiene copolymers are brominated using certain quaternary ammonium tribromides as the brominating agent. The bromination process proceeds easily under mild conditions, and produces a brominated product that has excellent thermal stability. A quaternary ammonium monobromide salt is produced as a reaction by-product. A solvent for the monobromide salt is added to the reaction after 25-90% bromination of the aliphatic carbon-carbon double bonds. This provides for significantly shorter reaction times while providing a product with few impurities.
摘要:
Butadiene copolymers are brominated using certain quaternary ammonium or phosphonium tribromides as the brominating agent. The bromination is performed in solution in a mixture of n-butyl acetate and ethyl acetate. The bromination process proceeds easily under mild conditions, and produces a brominated product that has excellent thermal stability.