Abstract:
Disclosed are a process and an apparatus for synthesizing nitroalkanes by reaction of a hydrocarbon feedstock with aqueous nitric acid. Energy and capital costs may be reduced by recycling a majority of the aqueous phase back to the reactor.
Abstract:
The present invention relates to a continuously operated adiabatic process for the preparation of nitrobenzene by nitration of benzene with nitric acid and sulfuric acid, in which the dilute sulfuric acid obtained after the nitration has taken place and the crude nitrobenzene has been separated off from the aqueous phase is concentrated for the purpose of re-use in the nitration, and after its concentration, at least one minute before it comes into contact with fresh nitric acid again an oxidizing agent is added such that a concentration of the oxidizing agent of from 10 ppm to 5,000 ppm, based on the total weight of the concentrated sulfuric acid to be recycled into the nitration, is established.
Abstract:
The present invention relates to aggregate zeolitic adsorbents based on zeolite X and zeolite LSX.These adsorbents are particularly suitable for separating C8 aromatic isomers and in particular xylenes, separating sugars, separating polyhydric alcohols, separating isomers of substituted toluenes, separating cresols, separating dichlorobenzenes.
Abstract:
The invention relates to a process for purifying crude aromatic nitro compounds which originate from the nitration of aromatic compounds, comprising the single or multiple performance of the following wash stage (a):(a) contacting the crude aromatic nitro compound (N-in) with an aqueous phase (W-res) and then separating the phases to obtain an organic phase (N-res) and an aqueous phase (W-res),wherein at least one demulsifier (D) is present in one or more of the wash stages (a).
Abstract:
Methods for the separation of targeted components from gun propellant formulations. In particular, the methods separate targeted components in a usable/useful form. Preferred methods are directed to the separation of nitrocellulose, nitroguanidine and/or nitroglycerine from a formulation containing one or more of these components.
Abstract:
Disclosed is a novel process and novel intermediates to prepare [R-(R*,R*)]-N-[3-[1-[5,6-dihydro-4-hydroxy-2-oxo-6-(2-phenylethyl)-6-propyl-2H-pyran-3-yl]propyl]phenyl]-5-(trifluoromethyl)-2-pyridinesulfonamide (XIX) ##STR1## which is a protease inhibitor useful in treating humans infected with the HIV virus.
Abstract:
Mono- and di-derivatives of cyclodextrins are completely defined, also a method for their synthesis and purification, functionalised cyclodextrins obtained from these derivatives, and the synthesis of supports comprising these cyclodextrin derivatives. Use of the supports for the preparation of separation of enantiomers, for asymmetric synthesis, for catalysis, for the preparation or separation of geometrical isomers or positional isomers, or for the preparation or separation of organic molecules with a hydrophobic nature is also described.
Abstract:
Mononitrohalogenobenzenes can be prepared by mixing halogenobenzene, nitric acid, sulphuric acid and water intensively with one another, simultaneously or in succession in their total quantity, and by redispersing them at least twice in the case of continuous preparation, applying a mixing energy of 1-40 watts per liter of the overall reaction mixture, preferably 3-30 W/l, largely suppressing back-mixing in the continuous procedure, and observing adiabatic reaction conditions.
Abstract:
Dinitrotoluene is produced in a two-stage process from toluene and nitric acid in the presence of sulfuric acid under adiabatic conditions in the presence of nitrating acids made up of specified components. The reaction product of the first phase is separated into an acid phase and an organic phase containing the mononitrotoluene. Some water is removed from the acid phase, nitric acid is added and the resultant mixture is recycled. The organic phase containing mononitrotoluene is further nitrated to produce the dinitrotoluene. This nitration mixture is also separated into an acid phase and an organic phase. The acid phase is treated to remove some water, nitric acid is added and the resultant acid mixture is recycled. Dinitrotoluene is recovered from the organic phase. This process is advantageous in that dilute nitric acid may be used and the heat of the nitration reaction is utilized.
Abstract:
Mononitrotoluenes can be prepared by intensively mixing together toluene, nitric acid, sulphuric acid and water, simultaneously or successively in their total amount, and, in the case of continuous preparation, redispersing the mixture at least twice, for which purpose a mixing energy of 1 to 40 watts per liter of the total reaction mixture, preferably 3 to 30 W/l, is employed per volume of the reactor, and, for the continuous procedure, the back mixing is substantially repressed. Adiabatic reaction conditions are maintained.