by The Unique Properties of Mesitylene: An Organic Chemical Compound
What is Mesitylene?
Mesitylene, also known as 1,3,5-trimethylbenzene, is an organic compound consisting of a benzene ring with three methyl substituents arranged symmetrically around the ring. It is a clear, colorless liquid that is insoluble in water but soluble in organic solvents. Mesitylene is classified as an aromatic hydrocarbon and is rarely found in its unsubstituted form in nature.
Chemical and Physical Properties
Mesitylene has the chemical formula C9H12 and a molar mass of 120.194 g/mol. It is a component of various essential oils obtained from plants and it has a sweet, pleasant odor often described as reminiscent of hay or grass. Mesitylene is denser than water with a density of around 0.86 g/cm3. Its melting point is -35°C and boiling point is 165°C. Being an asymmetric molecule, mesitylene exists as three structural isomers – 1,3,5-trimethylbenzene, 1,2,4-trimethylbenzene, and 1,2,3-trimethylbenzene. However, 1,3,5-trimethylbenzene is the most stable and predominant isomer found in nature.
Production and Industrial Uses
Commercially, mesitylene is produced through catalytic methylation of toluene or disproportionation of xylenes. It finds a variety of industrial applications where its properties as a non-polar organic solvent are exploited. Mesitylene is used as an intermediate in the synthesis of dyes, pharmaceuticals, and fragrance chemicals. Due to its inert and non-reactive nature, it is also used as a solvent in the industries that manufacture rubbers, polymers, resins, coatings, and agrochemicals. Mesitylene is combined with other solvents to make paint thinners and industrial degreasing formulations. It also serves as an important raw material in the production of synthetic musks and is commonly added to perfumes and incense formulations for its pleasant odor.
Safety Profile and Regulations
Being a hydrocarbon, mesitylene is considered combustible and somewhat toxic if inhaled or ingested in large amounts. The recommended exposure limits for mesitylene in the workplace are set at 25 ppm over an 8-hour time-weighted average by the American Conference of Governmental Industrial Hygienists (ACGIH). Short-term exposure at concentrations above 250 ppm may cause irritation to eyes and respiratory tract in humans. Mesitylene is classified by the EPA (Environmental Protection Agency) as a VOC (volatile organic compound) due to its participation in atmospheric photochemical reactions and contribution to ozone depletion and smog formation. Most regulatory agencies require the amount of mesitylene in final products to be limited or substituted wherever possible by less hazardous alternatives. Proper precautions must be taken during the industrial handling and storage of mesitylene to prevent risks to human health and environment.
Uses in Flavor and Fragrance Industry
Mesitylene is a widely employed chemical in the flavor and fragrance industry. Its sweet, grassy aroma makes it a popular ingredient in the formulation of several perfume types including fougères, chypres and green floral fragrances. Mesitylene is commonly formulated at levels less than 1% to reinforce the top, heart and drydown notes of fragrances. In perfumery, it is frequently combined with galaxolide, hedione and other musks to lend a natural, green touch. The olfactory properties of mesitylene are also exploited in food and beverage flavors. It finds use as a flavoring agent in candy, baked goods, chewing gum, soft drinks and many other products to contribute notes of fresh hay or green grass. Mesitylene also enhances tobacco flavors and formulations. Its solvent properties further aid in the incorporation and stabilization of other aromachemicals in liquid fragrance and flavor concentrates.
Conclusion
In summary, mesitylene is an important and versatile aromatic hydrocarbon primarily used as a chemical intermediate and industrial solvent across multiple sectors. Its unique chemical properties combined with a pleasant, natural odor profile have resulted in widespread applications of mesitylene in perfumery, flavors and other commercial formulations. While precautions must be taken regarding its combustion risks and environmental impact, mesitylene continues to be a valuable building block in organic synthesis and flavor/fragrance development due to availability, stability and cost factors. Future uses of this organic compound are expected to further expand its commercial utility. ___________________________________________________________________________
