Nitroparaffins Chemische Eigenschaften,Einsatz,Produktion Methoden
Industrielle Verwendung
Nitroparaffins are commonly referred to as nitroalkanes and are versatile solvents which have an electronegative nitro (-NO2) group attached to a methane, ethane, or propane molecule. Attachment of the nitro group is through a bond between the nitrogen atom and the alkane carbon atom. Nitromethane, nitroethane, 1-nitropropane, and 2-nitropropane are commercial solvents used in coatings, as solvents for chemical synthesis work, and as chemical intermediates for a wide variety of products. The nitroalkanes have unusually high Hansen polarity character and low hydrogen bonding which can be useful in the solubilization of a large number of resins. Solvent blends based on the nitroparaffins are useful for dissolving polyurethane elastomers. Nitromethane is the solvent of choice for acyanoacrylates. The nitroalkanes, which are miscible with aromatic hydrocarbons, alcohols, esters, and ketones, afford many solvent blends useful in the coating industry. The nitroalkanes are useful in extractive distillation processes based on the azeotropes the nitroalkanes form with many industrial solvents. Use of the nitropropanes in solvent blends result in shorter drying times for flexographic and gravure inks. Nitroparaffins afford an unique reaction medium for Friedel-Crafts reactions since these solvents will dissolve Lewis acid catalysts such as anhydrous aluminum chloride, boron trifluoride, titanium tetrachloride, and stannic tetrachloride. The role of nitromethane as a metal stabilizer for various chlorinated and fluorinated solvents involves its ability to complex with metal salts like aluminum chloride from the solvent-metal reaction.
Other miscellaneous uses for the nitroalkanes include their use as fuels in racing
cars and model engines, their ability to displace water from metal surfaces during
metallic pigment grinding operations, and as chemical intermediates. The
nitroparaffins produced by the vapor phase nitration of propane or ethane are
available from two United States production facilities: Angus Chemical Company
(Sterling, LA) and W. R. Grace and Company (Deer Park, TX). The nitroalkanes
are named as derivatives of the hydrocarbon with the prefix "nitro." The primary
or secondary position of the nitro group on propane is indicated by the number 1 or
2. The structure of nitromethane is CH3NO2, CH3CH2NO2 is nitroethane,
CH3CH2CH2NO, is 1-nitropropane, and CH3CH(NO2)CH3 is 2-nitropropane.
The nitroparaffins are excellent solvents for various resins and polymer compositions
in the coating industry. Few solvents have the high polarity character and
low hydrogen bonding values shown by the nitroalkanes. Nitromethane is the solvent of choice for a-cyanoacrylates. Polyurethane elastomers may be dissolved
easily in solvent blends' containing a nitroparaffm. Improved solvency for resins
and polymer compositions is afforded by the fact that nitroalkanes are miscible with
aromatic hydrocarbons, alcohols, esters, and ketones often used as components in
solvent blends. Nitroparaffins are excellent solvents for use in electrostatic spray
coatings because of their high dielectric constants. Nitropropane is useful for
adjusting the resistivity of coating formulations in order to achieve maximum
electrostatic efficiency. The mid-range evaporation rates (0.88-1.39; n-butyl acetate
= 1.0) of the four nitroalkanes help avoid the coating problems of solvent popping
and blushing which are often caused by faster evaporating solvents. The azeotropes
of nitroalkanes with a wide variety of industrial solvents allow decreased drying
times in flexographic and gravure printing inks. Nitropropane improves the wetting
of pigments during the grinding operation.
Nitroparaffins Upstream-Materialien And Downstream Produkte
Upstream-Materialien
Downstream Produkte
