Aromaticity method

NIOSH. Hydrocarbons, aromatic method 1501. NIOSH Manual of Analytical Methods (NMAM). 2003. 

EPA. 1991c. Method 602 - Purgeable aromatics Method 610 - Polynuclear aromatic hydrocarbons Method 625 - Base/neutrals and acids. U.S. Environmental Protection Agency. Code of Federal Regulations. 40 CFR 136, Appendix A. 

Three purge and trap methods are used to determine 29 halocarbons (Method 601), seven aromatics (Method 602, including four of the halo-carbons), and acrolein and acrylonitrile (Method 603). The three methods are distinctly different in the sorbent trap materials, GC columns, and... 

The aromatic method uses as its primary analytical column a packed column of 5% SP-1200 + 1.75% Bentone 34 on Supelcoport (100-120 mesh). The carrier gas is helium at a flow rate of 30 mL/min. The temperature is programmed as follows (for lower boiling compounds) 50 °C isothermal for 2 min, then 6 °C/min, then 6 °C/min to 90 °C, and then held until all compounds have eluted (for a higher boiling range of compounds) 50 °C isothermal for 2 min, then 3 °C/min to 110 °C, and then held until all compounds have eluted. A photoionization detector with a 10.2-eV lamp is used for measurement. 

Colour Tests. Aromaticity (Method 2)—yellow/red Liebermann s Test (100°)—blue. 

Colour Tests. Aromaticity (Method 2)—yellow/orange Lieber-mann s Test (100°)—blue (3 min) Sulphuric Acid—violet (blue fluorescence at 350 nm). 

Colour Test. Aromaticity (Method 2)—colourless (heat for 3 min)/red. 

Several aromatization methods have been published for the conversion of pyrazolines 226 into pyrazoles 227 and conditions are presented in Table 6. 

The focus of this study is to find out to what extent different exocyclic (C=X) substituents induce aromaticity and antiaromaticity in cyclopropene derivatives (HC)2C=X [32]. Although the consensus opinion suggests that parent methylenecy-clopropene, (HC)2C=CH2, the simplest cross-conjugated cyclic hydrocarbon, is nonaromatic, it is admitted that cyclopropenone is at least modesdy aromatic [33-35]. However, quantitative assessments of the aromaticity of other (HC)2C=X derivatives have not led to satisfactory agreement. Thus, this family of compounds represents a paramount opportunity to use the EDA-aromaticity method to give a definitive answer to a question that has been controversially discussed in the literature for several decades [33-35]. 

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