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Chemical product profile

HONGKUN / PRODUCT DIRECTORY

4-Nitro-o-xylene | CAS 99-51-4

A defined nitroxylene precursor to 3,4-dimethylaniline, where the adjacent methyl pattern and nitro-group position determine the aromatic amine obtained and make positional-isomer control a central purchasing requirement.

CAS99-51-4
Molecular formulaC8H9NO2
Molecular weight151.16 g/mol

Product overview

4-Nitro-o-xylene places a nitro group on a benzene ring bearing adjacent methyl substituents. The alternative name 1,2-dimethyl-4-nitrobenzene describes the same connectivity. Reducing the nitro group gives the 3,4-dimethylaniline framework, so a different nitroxylene isomer is a different feedstock even when formula and total aromatic content appear similar. Procurement should focus on the positional composition rather than an unspecified nitroxylene assay. Ask for chromatographic resolution of relevant isomers and identify how residual xylene is measured. Water and acidity can be specified where they affect the receiving reduction process, with acceptance values agreed against the actual route rather than assumed from the catalogue identity.

Chemical identity

Chemical name
4-Nitro-o-xylene
CAS number
99-51-4
Molecular formula
C8H9NO2
Molecular weight
151.16 g/mol

Application context

Published reduction chemistry converts 4-nitro-o-xylene into 3,4-xylidine, retaining the two carbon-bound methyl groups while changing the nitro substituent into an amino group. This gives the material a defined role at the nitroaromatic-to-aromatic-amine stage of a synthesis. Isomer composition matters because the substituent arrangement passes into the resulting xylidine.

In raw-material qualification, compare the chromatographic identity of the proposed lot with the isomer requested by the route. Specify the residual hydrocarbon fraction and quantitative content basis used to calculate the charge. Where acidity or water could influence the chosen catalyst or work-up, include those tests in the enquiry and agree methods with the proposed source. A representative sample can then be evaluated for conversion and downstream impurity behaviour within the buyer’s established process.

Chemistry and synthetic role

The nitro group is the functionality changed in the documented reduction. The methyl positions remain fixed, giving the 3,4-xylidine substitution pattern after renumbering from the amino group.

Quality review

Resolve nitroxylene isomers

Require a chromatogram and identification capable of distinguishing the selected 4-nitro-o-xylene structure.

Account for residual hydrocarbon

Specify residual xylene and the assay basis used for reaction-charge calculations.

Match acidity and water tests

Include these controls when justified by the receiving reduction, with agreed methods and limits.

Preparing a specification

Specify CAS 99-51-4 and 1,2-dimethyl-4-nitrobenzene, isomer-resolving purity, residual xylene and assay basis. Add acidity or water criteria according to the selected reduction route.

Packaging and storage

Confirm container, closure and net weight for the proposed material. Storage and transport instructions should follow the actual supplier SDS and label.

Documentation

Request identity data, COA, SDS and an isomer-resolving chromatogram; confirm hydrocarbon, water and acidity results required by the process.

Procurement questions

Does 1,2-dimethyl-4-nitrobenzene denote the same product?

Yes. It is the systematic description of 4-nitro-o-xylene.

Which xylidine follows nitro reduction?

The documented transformation gives 3,4-dimethylaniline, also called 3,4-xylidine.

Can total nitroaromatic content qualify the isomer?

It must be complemented by structural identification and an isomer-selective analysis.

Technical sources
  1. PubChem CAS-resolved identity, CID 7440NCBI / National Library of Medicine
  2. 1,2-Dimethyl-4-nitrobenzene N28604Sigma-Aldrich
  3. Selective reduction of nitroaromatics, US3906045AGoogle Patents / patent publication
  4. Preparation of 4-nitro-o-xylene, US20040192977A1Google Patents / patent publication