How is ethanol denatured

The idea was to scare people into giving up illicit drinking. Instead, by the time Prohibition ended in , the federal poisoning program, by some estimates, had killed at least 10, people 2. There was benzene, there was mercury, there was this list of formulas that's heart-stopping horrible.

Ethanol is the commonly used dehydrant in histology. However, because it is drinkable, pure ethanol is taxed and regulated in many countries. Ethanol is also available with chemicals added to make it undrinkable. These government approved denatured formulations are less regulated and require minimal documentation to purchase.

Looking at those MSDS available on-line can give us some indications. Methyl isobutyl ketone - The typical toxicity effects of Methyl isobutyl ketone in humans exposed at 50 to ppm are mucous membrane irritation and weak effects on the central nervous system CNS such as headache. Denatonium Benzoate - Denatonium benzoate gets its name from "denatured alcohol", and that is where it is often used. The first substance fusel oil is a waste product of the bioethanol distillation, thus it would be economically attractive to turn it into a valuable side-product by using it as denaturing agent.

However, fusel oil adsorbs strongly and in alkaline medium even irreversibly onto the platinum surface, thereby lowering the current densities for the ethanol oxidation tremendously.

As fusel oil is furthermore only poorly soluble in aqueous media, it turned out to be incompatible with the use as denaturing agent in DEFC.

Furthermore, its chemical structure has some similarities with the one of ethanol. While in acidic environment the current densities obtained with ethanol denatured by ETBE are slightly smaller compared to pure ethanol, especially in alkaline medium, the differences between denatured and pure ethanol are insignificant.

The shape of the cyclic voltammograms thereby resembles the one for ethanol. Denatonium benzoate Bitrex is a widespread adjuvant to a denaturing agent. It could be shown, that in the intended concentrations Bitrex behaves almost inert in acidic and alkaline environment. As the taste of Bitrex is extremely bitter, only very small amounts of Bitrex are needed for the purpose of denaturing.

Adding Bitrex as adjuvant to another denaturing agent offers the possibility to lower the content of that denaturing agent. So with the perspective of lowering the ETBE concentration and thereby omitting its adverse effects on the ethanol oxidation especially in acidic environment, a mixture of ETBE and Bitrex was tested.

Investigations at commercial fuel cell catalysts and in single cell fuel cells reveal that the effects on the performance depend strongly on the catalyst used.

Taking into account the presented results it can principally be stated that the mixture of ETBE and Bitrex is a promising candidate as denaturing agent for ethanol as fuel for DEFC. This applies to the acidic medium as well as to the alkaline environment. However, the exact composition of such a mixture of denaturing agents needs to be investigated in cooperation with the customs authorities.

Therefore, more work especially in fuel cell testing under standardised conditions needs to be done. This is an open access article distributed under the Creative Commons Attribution License , which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Article of the Year Award: Outstanding research contributions of , as selected by our Chief Editors. Read the winning articles. Journal overview. Special Issues. Academic Editor: Dingsheng Yuan. Received 12 Mar Accepted 04 May Published 13 Jul Abstract Acidic or alkaline direct ethanol fuel cells DEFCs can be a sustainable alternative for power generation if they are fuelled with bio-ethanol.

Introduction As fossil fuels run short and the problem of environmental pollution is getting serious, fuel cells offer an alternative of clean and sustainable power generation. Experimental The electrochemical experiments were performed in three-electrode configuration in a glass cell which can be refilled from the top and drained through a bottom valve.

Results As a starting point, three interesting substances were chosen from the variety of chemicals which are used as denaturing agents for different purposes. Figure 1. Chemical structures of tert-butyl ethyl ether ETBE a and denatonium benzoate phenylmethyl-[2-[ 2,6-dimethylphenyl amino]oxoethyl]-diethylammonium benzoate, Bitrex b. Figure 2. Electrochemical behaviour of potential denaturing agents in 0.

Figure 3. Cyclic voltammetry of ethanol and denatured ethanol solutions in 0. Table 1. Figure 4. Mass fragments and assignment of substances as indicated in the graphs. Figure 5. Figure 6. Figure 7. Fuel cell tests of pure ethanol grey , ethanol solutions containing a mixture of ETBE and Bitrex black in acidic a and alkaline environment, b.

References T. View at: Google Scholar H. Tang, S. Wang, M. Pan, S. Jiang, and Y. Antolini and E. Cheng, Z. Shi, N. Glass et al. Biegler, D. Rand, and R. View at: Google Scholar C. Cremers, D. Bayer, B. Kintzel et al. View at: Google Scholar D. Kintzel, M. Joos, C. Cremers, and J. Wang, G. Sun, L. This entry was posted in Demonstrations on April 10, by Michael Parker. EkoFuel Bioethanol Compare Items.

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