Abstract:
A method of providing a reagent into a chemical process said provision being in the vapor phase and at a controlled mass flow rate wherein the method comprises:(a) providing a gas stream which contains a gaseous phase complexing agent for the reagent said complexing agent being provided at a controlled partial vapor pressure in said gas stream;(b) providing a primary source of the reagent in a reservoir which is connected to the gas stream via a diffusion path;(c) causing the gaseous phase complexing agent to diffuse into the reservoir at a mass flow rate controlled by its partial pressure in the gas stream;(d) causing the gaseous phase complexing agent in the reservoir to react with the primary source to generate a gaseous phase complex of the reagent and the gaseous phase complexing agent, said generation being, in the steady state, at a rate equivalent to the rate of inflow of said complexing agent;(e) causing the gaseous phase complex to diffuse out of the reservoir into the gas stream at a rate, in the steady state, which is equivalent to its rate of generation in stage (d);whereby the mass flow of reagent occurs at a rate defined and controlled by the vapor pressure of the vapor phase complexing agent in the gas stream.
Abstract:
Biodegradable hollow fibres with an asymmetric wall, the cavity of which containing an active substance like a drug, hormone etc. or a dilute form of the latter and both ends of the hollow fibre being closed for the controlled release of the active substance as well as a process for the manufacturing of such hollow fibres.
Abstract:
A device is provided for conveying separately at least two gases as far as a mixing zone, said device including several tubes, and means for supplying these tubes with one of the gases, the invention also relating to a reactor having at least one cell equipped with said conveying device, said device further including means for holding the tubes in position with respect to each other, the tubes being held together jointingly by said means and defining empty spaces or intertube gaps, some at least of said tubes having narrowed zones placed substantially at the same level so as to form a network for distributing the other gas to some at least of the intertube gaps.
Abstract:
Trickle bed reactors are prone to channelling, flooding, and similar flow problems. It has been found that these problems can be avoided by the use of a microporous membrane to separate a reactant fluid phase from a catalysis fluid phase surrounding a catalyst bed. An advantage of such a reactor is that the fluid flows can be separately controlled. An apparatus useful as a trickle bed reactor can include a plurality of microporous hollow fibers arranged in a shell-and-tube configuration within a housing. Such an apparatus is operated with a reactant fluid phase flowing through the fibers and with a catalyst bed on the shell-side of the arrangement.
Abstract:
A method of heterogeneous reaction is described, comprising reacting a water-soluble component and an oil-soluble component dispersed in the water-soluble component or an aqueous medium containing the same. This dispersion is attained by passing the oil-soluble component through the micropores of a hydrophilic material as it is introduced into the aqueous medium. This hydrophilic material can be shaped into a desired form such as a membrane and a fabric. The flow rate, reaction rate and conversion are easy to control in the present method since the particle size of the oil-soluble component can be appropriately controlled. Furthermore, the present method does not need any stirring power nor an emulsification operation, and thus is advantageous from an economic standpoint.
Abstract:
This invention relates to a process for the encapsulation in human or animal erythrocytes of at least one substance having a biological activity, characterized in that the primary compartment of at least one dialysis element is continuously supplied with an aqueous suspension of erythrocytes, the secondary compartment of the dialysis element contains an aqueous solution which is hypotonic with respect to the erythrocyte suspension in order to lyse the erythrocytes, the erythrocyte lysate is in contact with said substance having a biological activity and, in order to reseal the membrane of the erythrocytes, the osmotic and/or oncotic pressure of the erythrocyte lysate is increased after it has been brought into contact with said substance having a biological activity.
Abstract:
A delivery device for zero-order release of an active principle into a dissolution fluid includes a reservoir consisting of a solid matrix of a homogeneous mixture of a polymer material, at least a portion of the active principle and an additive soluble in the dissolution fluid with negative heat of solution, a coating on the solid matrix-type reservoir of a first, release rate-controlling insoluble membrane which modulates the active principle release according to the desired kinetics; and a second, protective membrane on the release rate-controlling membrane of a soluble polymer material.
Abstract:
A method for the bubble-free feed of gaseous reactants of a chemical and/or biological reaction into a liquid reaction medium, characterized by filling the pores of a porous polymer membrane with the reaction medium, providing one side of the porous polymer membrane with the gaseous reactants, and immersing the other side of the porous polymer membrane into the liquid reaction medium. The pressure of the gaseous reactants should lie below the bubble pressure determined for the reaction medium, but be at least so great that the liquid reaction medium does not pass through the porous polymer membrane to the gas side. Preferred parameters include relative pore volume between 50 and 90%; maximal pore diameter between 0.2 and 3 .mu.m; and disposing the porous polymer membrane in the form of a flat membrane, tube or hollow filaments.
Abstract:
Disclosed is a method of carrying out a mobile atom insertion reaction, such as a hydrogen insertion reaction, for the synthesis of reduced, hydrogenated compounds. Such reactions include the production of ammonia and hydrazine from nitrogen, formic acid and methanol from carbon dioxide, and hydrogen peroxide from oxygen. The insertion reactions are carried out at a bipolar mobile atom transmissive membrane comprising a membrane formed of a mobile atom pump material, as a hydrogen pump material, conductive atom transmissive means on one surface of the membrane and conductive atom transmissive means on the opposite surface of the membrane. The mobile atom, such as hydrogen, diffuses across the membrane, to provide a source of hydrogen on the insertion reaction side of the membrane. The insertion reaction side of the membrane is positively biased with respect to a counterelectrode so that a reactant molecule, such as carbon dioxide, is electrosorbed on that surface of the membrane. The electrosorbed reactant molecule chemically reacts with the surface hydrogen by the insertion reaction to form a reduced, hydrogenated product such as formic acid. Also disclosed is a chemical reactor, containing the membrane, and several electric field assisted chemical reactions utilizing the membrane and reactor.
Abstract:
An osmotic device is disclosed comprising a semipermeable wall surrounding a compartment housing an agent that is insoluble to very soluble in aqueous and biological fluids, and a layer of a fluid swellable, hydrogel. A passageway in the wall connects the agent with the exterior of the device.