The Advantages And Disadvantages Of An Esters

Ethyl ethanoate: Ethyl ethanoate is an ester. Esters are group of organic compounds which have a functional group of –COO-. Esters are liquids that become vapours quickly so they are present in perfumes.

In this experiment, the Fischer Esterification of an unknown acid and an unknown alcohol was used to prepare an unknown ester. Sulfuric acid was used as a catalyst in the reaction which then was put under reflux. After cooling, the pH of the solution was raised to approximately 8 using sodium carbonate. Diethyl ether was added, then the aqueous layer was removed and the organic layer was washed with sodium chloride. The aqueous layer was removed again and sodium sulfate was added. The unknown product was then identified using gas chromatography (GC) to obtain the retention time.

Esters have small molecular weight and most known for their pleasant aroma. Similar to the unique emission spectrum for different chemical element, different esters release a distinct

In the Casey Anthony case Jeff Ashton who is a former state attorney in Orange county Florida, and also the first prosecutor in the United States to get a conviction based on DNA decided to use a new Forensic method in the Anthony case. The smell of death would be the allowed as evidence for the first time ever. In the trunk of Anthony’s car was a stained area on the carpet and an odor. Ashton stated that the smell was that of human decomposition. That piece of carpet was removed, sealed and sent to Dr. Vass, a forensic anthropologist at Oak Ridge National Laboratory. Dr. Voss has been studying human decomposition at the University of Tennessee’s “body farm”.

Aroma compounds are simply the components responsible for odors in food. The aroma of a food does not come from one particular component, but comes from the combination

At room temperature (25°C), esterification reactions are relatively slow, therefore requiring the rate of the chemical reaction to be increased for the products to be formed efficiently. This is implemented, by using a catalyst, such as concentrated sulphuric acid (H2SO4 (aq)), as well as by heating the mixture: using a heating mantle. As a result, the energy of the reactants can be greater than the activation energy, increasing the rate of reaction. Hence, as the reactants are relatively volatile, so reflux apparatus such as a pear-shaped flask and a Liebig condenser were used, to minimise the amount of reactants lost, as well as allow the reaction to take place at the highest temperature possible. In addition, boiling chips were added prior to reflux, to prevent bumping and a decrease a loss of volatile reactants, during the reflux

An ester was synthesized during an organic reaction and identified by IR spectroscopy and boiling point. Acetic acid was added to 4-methyl-2-pentanol, which was catalyzed by sulfuric acid. This produced the desired ester and water. After the ester was isolated a percent yield of 55.1% was calculated from the 0.872 g of ester recovered. This quantitative error was most likely due to product getting stuck in the apparatus. The boiling point of the ester was 143° C, only one degree off from the theoretical boiling point of the ester 1,3-dimethylbutyl, 144 ° C. The values of the

We all fancy individual aromas and do not fancy others, and some aromas can even change the way we feel or occasionally bring up old memories. That's the reason perfumes and colognes are so trendy.

One of the major elements of human attraction is pheromones. Pheromones are biochemical molecules that can take many different forms, such as skunk spray, or pheromones in bees that direct them to flowers, or even sex pheromones. According to Psychology Today, The evaluative sniffing that mammals engage in during courtship were clues that scent is the chemical equivalent

There are various factors that can affect the sensitivity of our nose towards the odorants. Human, in fact, has an extraordinary superb sense of smell. We can sense the smell of sweat when we are in fear. We can detect and identify an odorant even at an extremely low concentration. We can also improve our sense of smell by practicing. (Sela & Sobel, 2010)

From Figure 1.2.1., there are 6 odourant samples (vinegar, black pepper, ginger, chocolate flavour, olive oil and bay leaf) have higher frequency of usage than accuracy of identification, while 4 samples (vanilla extract, cherry flavour, turmeric, mint) are the opposite.

Next, we looked at the olfactory responses of the remaining six odorants from the panel of seven that were mentioned above. As mentioned in the previous paragraph, starved and non-starved larvae were subjected to the two-choice assay after 2 hours of the starvation protocol. Data collected for all seven different odorants are shown in Figure 2. Of all the seven odorants tested, only three odorants showed significant changes in response indices upon starvation. Acetal (shown in Figure 1), 4, 5-dimethylthiazole, and pentyl acetate were the three odorants that showed higher RI values for starved state larvae when compared to non-starved larvae. In other words, for these three odorants starved larvae had higher attractiveness towards odorants compared to non-starved larvae. This supported our hypothesis that individual ORNs might be differentially modulated by the animal’s starved state.

In the earlier study, scientists assumed that people could only discern about ten different intensities in each of four odor “qualities,” which were either fragrant, acidic, capric (like sweat), or burnt. All of the options amounted to the 10,000 number (10x10x10x10). In the new study, the researchers combined 128 odor molecules from a wide range of smells into various, unique mixtures. The mixtures contained 10, 20 or 30 different components. And rather than employ professional sniffers for the testing, they found volunteers from the community to participate in the study.

Semiochemicals are organic molecules that transmit chemical messages within the same or different species of animals and plants. There are multiple distinctions within semiochemicals like pheromones, kairomones and allomones (Zumdahl, 1989). Pheromones are chemicals that have an effect on the receptors within similar species of the producer, and they tend to be highly volatile compounds (ibid). There are different types of pheromones according to the response they stimulate on the receiving party, as shown in figure 1. Volatile pheromones are represented as either sex or defensive pheromones and they usually produce a specific odor.

* Fruits: Fresh fruits such as apples, strawberries, cherries unfortunately do not yield the expected odors when extracted; if such fragrance notes are found in a perfume, they are synthetic. Notable exceptions include litsea cubeba, vanilla, and juniper berry. The most commonly used fruits yield their aromatics from the rind; they include citrus such as oranges, lemons, and limes. Although grapefruit rind is still used for aromatics, more and more commercially used grapefruit aromatics are artificially synthesized since the natural aromatic contains sulfur and its degradation product is quite unpleasant in smell.