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Contaminants Dissolved in the Water Film Surrounding Soil Particles in the Unsaturated Zone
Published in Warren J. Lyman, Patrick J. Reidy, Benjamin Levy, Chi-Yuan Fan, Mobility and Degradation of Organic Contaminants in Subsurface Environments, 2020
Warren J. Lyman, Patrick J. Reidy, Benjamin Levy, Chi-Yuan Fan
The following conclusions are among those drawn by Rice et al. (1981) with respect to ozonation: Saturated aliphatic hydrocarbons are unreactive with ozone.Alcohols are slowly oxidized to aldehydes and ketones, which then slowly oxidize to acids.Benzene is slowly oxidized, and other aromatics are easily oxidized except when electron-withdrawing constituents are present.Reaction products are more polar and more readily biodegradable.Complete reaction to CO2 and water rarely occurs.
Applied Chemistry and Physics
Published in Robert A. Burke, Applied Chemistry and Physics, 2020
Each of the hydrocarbon derivative families has certain hazards and characteristics associated with the family. So, if one compound in the family has certain characteristics, then so will most of the others. Alkyl halides as a family may be toxic and flammable although all are not. Nitro compounds are explosive! They could also be considered flammable and perhaps in some cases toxic, however who cares! They are going to go BOOM, and that is what will more likely injure or kill response personnel. Amine compounds may be toxic and flammable. Cyanides are toxic. Ethers are flammable and have wide flammable ranges; additionally, they are anesthetics and, in large enough concentrations, toxic, but so is water! So toxicity has to be looked at in relative terms. Ethers are a compound prone to form explosive peroxides as they age. Isocyanates are extremely toxic. Peroxides may form as the ether is exposed to air, particularly the oxygen in the air. Peroxide family compounds including the peroxides that are formed in ether are considered explosive. Sulfur oxides release hydrogen sulfide gas when burning. Alcohols have varying levels of toxicity and are flammable. Ketones are narcotic and flammable. Esters are flammable an will polymerize. Aldehydes are toxic by inhalation, irritants, flammable and carcinogens. Organic acids are corrosive, some are flammable and oxidizers.
INDUSTRIAL ORGANIC SOLVENTS
Published in Nicholas P. Cheremisinoff, Industrial Solvents Handbook, Revised And Expanded, 2003
The boiling points of alcohols are in general much higher than comparably sized ethers. That can be explained by the extra intermolecular forces between the alcohol molecules due to the hydrogen bonding. There is no such hydrogen bonding between the ether molecules because all the hydrogen atoms are not bonded to an oxygen or a nitrogen atom. Since there is not any possibility of hydrogen bonding the forces between the ether molecules are much weaker and can be much more easily vaporized. As an example, the boiling point of ethanol, CH3-CH2-O-H, is 78’C. The boiling point of the constitutional isomer dimethyl ether, CH3-O-CH3, is only -24°C, more than 100 degrees lower. Since the size of the molecules of the two compounds are approximately the same, this dramatic difference can only be explained by the presence of hydrogen bonding with the alcohol. Branching will tend to decrease the boiling point since a more symmetrical molecule will have less London dispersion forces and with more hydrocarbon branching around the carbinol carbon (carbon bonded to the hydroxyl group) the hydrogen bonding of fewer molecules results, and therefore the compound can be vaporized at a lower temperature. A dramatic example of this is found in the four carbon alcohols, l- butanol, 3-methyi-l-propanol, 2-butanol, and 2-methyl-2-propanol. They have boiling points of 118, 108, 100, and 83’C, respectively.
Bioethanol production from sugarcane molasses with supplemented nutrients by industrial yeast
Published in Biofuels, 2023
Hasan Shahriar Raby, Md Anowar Saadat, Ahmed Nazmus Sakib, Fatema Moni Chowdhury, Abu Yousuf
Alcohol is extensively used in the food industry as a beverage as well as in chemical feedstock, solvent, transportation fuel, metabolic or genetic processes in the living system [1], and for pharmaceutical purposes [2]. Hence, the enhancement of baker’s yeast production is one of the extensively researched biotechnological processes. High fermentation efficiency, rapid growth, and effective sugar utilization of Saccharomyces cerevisiae are indispensable for its industrial versatility. This type of yeast finds widespread use in alcohol production, and there is a vast body of scientific literature dedicated to studying the kinetics of alcoholic fermentation by yeasts. The yields of both growth and digestion end products have been examined in relation to the physicochemical changes of the culture medium caused by the buildup of either the end product- bioethanol, or co-metabolites, such as short-chain fatty acids, organic acids, and heavy esters [3–6]. Peña et al. [7] have attempted to analyze the influence of pH, and Alfenore et al. [8] studied vitamins and other researchers examined nutrient supplements for optimal results [9].
Exergy analysis of fusel oil as an alternative fuel additive for spark ignition engines
Published in Biofuels, 2023
Süleyman Üstün, Battal Doğan, Derviş Erol
Today, the world’s average surface temperature is increasing due to the increasing number of vehicles and the increasing amount of fossil fuels used. The most common effects of global warming and climate change, which manifest themselves with this increase in temperature in the atmosphere, are ocean warming, glacier melting, sea-level rise, an increase in extraordinary natural events, and similar developments. In this context, it has become a necessary to develop fuels that emit fewer harmful exhaust emissions into the atmosphere. Since the oxygen in the content of alcohols, among these alternative fuels, improves combustion efficiency, they release fewer harmful exhaust emissions into our environment than fossil fuels do. A lot of research and development studies have been carried out on the use of alcohols as alternative fuels instead of fossil fuels, from the invention of internal combustion engines to the present day [10,11]. Furthermore, alcohols also reduce the foreign dependency of the country’s economy because they are a clean energy source and can be produced from agricultural resources that can be grown locally in the country. Since the lower heating value of alcohols is lower than that of gasoline, when gasoline–alcohol blends are used in internal combustion engines, engine power decreases, and fuel consumption increases. However, studies in the literature demonstrate that gasoline–alcohol blends created in certain proportions do not have considerable adverse effects on engine performance characteristics [10–16].
Transesterification of vegetable oils into biodiesel by an immobilized lipase: a review
Published in Biofuels, 2023
Akossi Moya Joëlle Carole, Kouassi Konan Edmond, Abolle Abollé, Kouassi Esaie Kouadio Appiah, Yao Kouassi Benjamin
Alcohol is one of the most important raw materials to produce biodiesel. Alcohols are primary and secondary monohydric aliphatic alcohols comprising 1–8 carbon atoms. The transesterification reaction is also known as alcoholysis (methanolysis if methanol is used and ethanolysis if ethanol is used). Methanol is the most widely used alcohol in many alkyl ester synthesis processes because of its physical and chemical advantages [202]. The transesterification reaction can also be conducted with ethanol, specifically bioethanol. Although methanol and ethanol are the most frequently used, ethanol is the preferred alcohol because it can be derived from agricultural products, is renewable, and is biologically less objectionable in the environment. Methanol, in contrast, is primarily employed due to its low cost and physical and chemical advantages [203].