To obtain oils from plant materials steam distillation is typically used. Solvent extraction is also used to create a resinoid (resembling characteristics of resin). Solvent extraction is commonly used with volatile substances that may be lost with distillation. Solvent used are pentane, hexane, and mixes of solvents such as ethyl acetate and hexane which is commonly used in place of benzene (see Figure 2).
Gas-Liquid Chromatography is the process of separating complex mixtures into the components and measuring the individual components. By using injectors, columns, and detectors researchers are able to enhance the separation and identification of the components.
The volatile compounds of a fragrance can be found in the headspace, the air above and around a fragrant substance. This technique is mainly used when trying to collect the fragrance from flowers. Absorbent traps are used to collect the volatiles. Traps are small glass tubes containing activated charcoal. The air is ran through the tubes where the volatiles are collected from the flower which is enclosed inside a bell jar in order to prevent the volatiles from being taken away by the air. Once the traps are removed the traps must be kept cool and dark because of the reactive glass and absorbent surfaces that can cause materials to be ruined (Sells, 2006, p. 225).
The need for several flavors and fragrances exceeds the amount that is made naturally. The annual amount of vanillin used is 12,000 tons however only 1,800 tons of natural vanillin is produced (Crasto, 2012). Therefore, the extra amount needed is produced through chemical synthesis. The most recent and popular form is a two-step process in which guaiacol reacts with glyoxylic acid by electrophilic aromatic substitution. Electrophilic aromatic substitution is an organic reaction where an atom that is attached to an aromatic is replaced by an electrophile. An electrophile is a reagent that is attracted to an electron that is in a chemical reaction by accepting an electron pair in order to bond to a nucleophile (donates electron pair to electrophile). From this reaction vanillylmandelic acid is formed and turned by 4-hydroxy-3-methoxyphenylglyoxylic acid to vanillin by oxidative decarboxylation. During oxidative decarboxylation a carboxyl group (COOH) is removed forming carbon dioxide.
Perfume Ingredients from Benzene
2-phenylethanol is one of the most important ingredients made from benzene. It is part of rose oil and is widely used for its blending qualities. A way to create 2-phenylethanol is to hydrogenate styrene oxide. The production of styrene from benzene produces a good product and the intermediate, styrene oxide, can be used in other materials. By rearranging the epoxide (three atom cyclic ether) phenylacetaldehyde is produced, with a green note. By adding alcohols to styrene oxide the acetals (functional groups) of...