The present invention relates to a carbon nanotube preparation method and system, which may improve the overall efficiency and economic feasibility of a reaction by collecting fine particles including carbon nanotube particles that have not grown enough and an unreacted catalyst produced during and after the reaction by using a separator at the exterior of a fluidized bed reactor, and then, injecting the fine particles as a bed prior to a subsequent cycle.

Disclosed herein are methods and systems to produce ammonia from nitrogen and water. In an embodiment, a method of producing ammonia involves contacting nitrogen, water, and at least one superparamagnetic catalyst to form a mixture, and exposing the mixture to a fluctuating magnetic field. In some embodiments, the superparamagnetic catalyst is BVO.sub.2FeO.sub.2.

Techniques regarding post polymerization modifications to polycarbonate polymers via a flow reactor are provided. For example, one or more embodiments described herein can comprise a cyclic carbonate monomer that can be employed to facilitate polymerization of one or more polycarbonate platforms susceptible to post polymerization modification. For instance, one or more embodiments can regard a cyclic carbonate molecular backbone covalently bonded to an aryl halide functional group via in accordance with a chemical structure selected from the group consisting of: ##STR00001##
In the chemical structures, R.sub.1 can be selected from the group consisting of a hydrogen atom and a functional group comprising a first alkyl group; L can represent a linkage group, comprising: a second alkyl group and an end group having at least one member selected from the group consisting of an oxygen atom and a nitrogen atom; and A can represent the aryl halide functional group.

The present invention relates to an improved process for the preparation of trazodone. In particular, the present invention relates to a continuous process for the preparation of trazodone. More in particular, the present invention relates to a new method for the preparation of trazodone, said method comprising at least one step consisting of a continuous process performed in a flow reactor.

Reaction schemes involving acids and bases; reactors comprising spatially varying chemical composition gradients (e.g., spatially varying pH gradients), and associated systems and methods, are generally described.

A method for preparing an aliphatic isocyanate according to an exemplary embodiment of the present disclosure includes a first step of introducing an aliphatic amine and an organic solvent into a reactor, a second step of supplying gaseous hydrogen chloride into the reactor through a sparger, and a third step of stirring the aliphatic amine and the organic solvent, and the hydrogen chloride with a stirrer installed in the reactor, wherein in the third step, a stirring force of the stirrer is controlled to 500 to 4,000 W/m.sup.3.

The present invention refers to the use of hydrofoil impellers for the preparation of polymer polyols and to a method for preparing a polymer polyol, which comprises reacting a base polyol, at least one ethylenically unsaturated monomer and a macromer or a preformed stabilizer in the presence of a free-radical initiator and optionally a chain transfer agent in a reactor, wherein said reactor is stirred by means of a stirring system comprising a shaft rotatable about its longitudinal axis, and a plurality of radially extending hydrofoil impellers mounted on the shaft and respectively axially spaced apart and wherein the reactor does not contain baffles.

Reaction schemes involving acids and bases; reactors comprising spatially varying chemical composition gradients (e.g., spatially varying pH gradients), and associated systems and methods, are generally described. For example, methods comprising producing an acid and a base via electrolysis; dissolving a material comprising calcium using the acid to produce ions comprising calcium in a region of a reactor with a pH of 6 or less; precipitating solid calcium hydroxide from the ions comprising calcium using the base in a region of a reactor with a pH of 10 or higher; and utilizing the calcium hydroxide in a downstream process to form a cement are described.

Methods and systems for producing isosorbide from biomass are disclosed. In one embodiment, a method of producing isosorbide from biomass may include contacting biomass, a catalyst mixture of a noble metal and a first solid acid, and hydrogen to form a first reaction mixture, and heating the first reaction mixture to form at least one intermediate compound. Further, the intermediate compound is contacted with a second solid acid to form a second reaction mixture, and heating the second reaction mixture to form isosorbide.

Reaction schemes involving acids and bases; reactors comprising spatially varying chemical composition gradients (e.g., spatially varying pH gradients), and associated systems and methods, are generally described. For example, methods comprising producing an acid; dissolving a material comprising calcium in the acid to produce calcium ions; treating the calcium ions to produce solid calcium hydroxide and/or calcium oxide; and utilizing the solid calcium hydroxide and/or calcium oxide in a downstream process to produce a cement, wherein the downstream process comprises heating the solid calcium hydroxide and/or calcium oxide in a kiln are described.