Ethoxylation and propoxylation reactions are performed in the industry to produce mainly non-ionic surfactants and ethylene oxide(EO)–propylene oxide(PO) copolymers.Both the reactions occur in gas–liquid reactors by...Ethoxylation and propoxylation reactions are performed in the industry to produce mainly non-ionic surfactants and ethylene oxide(EO)–propylene oxide(PO) copolymers.Both the reactions occur in gas–liquid reactors by feeding gaseous EO,PO or both into the reactor containing a solution of an alkaline catalyst(KOH or Na OH).Non-ionic surfactants are produced by using liquid starters like fatty alcohols,fatty acids or alkyl-phenols,while when the scope is to prepare EO–PO copolymers the starter can be a mono-or multi-functional alcohol of low molecular weight.Both reactions are strongly exothermic,and EO and PO,in some conditions,can give place to runaway and also to explosive side reactions.Therefore,the choice of a suitable reactor is a key factor for operating in safe conditions.A correct reactor design requires:(i) the knowledge of the kinetic laws governing the rates of the occurring reactions;(ii) the role of mass and heat transfer in affecting the reaction rate;(iii) the solubility of EO and PO in the reacting mixture with the non-ideality of the reacting solutions considered;(iv) the density of the reacting mixture.All these aspects have been studied by our research group for different starters of industrial interest,and the data collected by using semibatch well stirred laboratory reactors have been employed for the simulation of industrial reactors,in particular Gas–Liquid Spray Tower Loop Reactors.展开更多
The system of electrons on liquid helium is an interesting candidate to implement quantum computation, due to the long coherence times of the qubits encoded by the electronic spins. In order to implement the quantum l...The system of electrons on liquid helium is an interesting candidate to implement quantum computation, due to the long coherence times of the qubits encoded by the electronic spins. In order to implement the quantum logic operations between the spins, we propose here a configuration, similarly to the cooled ions in a trap, to couple the distant electrons via manipulating their center of mass （CM） vibrations. First, we show that the electrons could be confined in a common harmonic oscillator potential by using an electrostatic field. Then, with a single current pulse （applied on the micro-electrode below the liquid helium） the distant electronic spins can be coupled simultaneously to the CM mode. Finally, by adiabatically eliminating the CM mode, effective interaction between the distant spins is induced for implementing the desired quantum computing.展开更多
文摘Ethoxylation and propoxylation reactions are performed in the industry to produce mainly non-ionic surfactants and ethylene oxide(EO)–propylene oxide(PO) copolymers.Both the reactions occur in gas–liquid reactors by feeding gaseous EO,PO or both into the reactor containing a solution of an alkaline catalyst(KOH or Na OH).Non-ionic surfactants are produced by using liquid starters like fatty alcohols,fatty acids or alkyl-phenols,while when the scope is to prepare EO–PO copolymers the starter can be a mono-or multi-functional alcohol of low molecular weight.Both reactions are strongly exothermic,and EO and PO,in some conditions,can give place to runaway and also to explosive side reactions.Therefore,the choice of a suitable reactor is a key factor for operating in safe conditions.A correct reactor design requires:(i) the knowledge of the kinetic laws governing the rates of the occurring reactions;(ii) the role of mass and heat transfer in affecting the reaction rate;(iii) the solubility of EO and PO in the reacting mixture with the non-ideality of the reacting solutions considered;(iv) the density of the reacting mixture.All these aspects have been studied by our research group for different starters of industrial interest,and the data collected by using semibatch well stirred laboratory reactors have been employed for the simulation of industrial reactors,in particular Gas–Liquid Spray Tower Loop Reactors.
基金Supported by the National Natural Science Foundation of China under Grant Nos.11204249,11174373the National Fundamental Research Program of China under Grant No.2010CB923104
文摘The system of electrons on liquid helium is an interesting candidate to implement quantum computation, due to the long coherence times of the qubits encoded by the electronic spins. In order to implement the quantum logic operations between the spins, we propose here a configuration, similarly to the cooled ions in a trap, to couple the distant electrons via manipulating their center of mass （CM） vibrations. First, we show that the electrons could be confined in a common harmonic oscillator potential by using an electrostatic field. Then, with a single current pulse （applied on the micro-electrode below the liquid helium） the distant electronic spins can be coupled simultaneously to the CM mode. Finally, by adiabatically eliminating the CM mode, effective interaction between the distant spins is induced for implementing the desired quantum computing.
