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Chemicals from Olefin Hydrocarbons
Published in James G. Speight, Handbook of Petrochemical Processes, 2019
Carbonylation refers to reactions in which the carbon monoxide moiety is introduced into organic and inorganic substrates. Carbon monoxide is abundantly available and conveniently reactive, so it is widely used as a reactant in industrial chemistry. Several industrially useful organic chemicals are prepared by carbonylation reactions, which can be highly selective reactions. Carbonylation reactions produce organic carbonyl derivatives, i.e., compounds that contain the carbonyl (C=O) functional group such as aldehyde derivatives (–CHO), ketone derivatives (>C=O), carboxylic acid derivatives (–CO2H), and ester derivatives (–CO2R, where R is an alkyl group). Carbonylation reactions are the basis of two main types of reactions (i) hydroformylation and (ii) the Reppe reaction.
Impact of Silane Treatment on the Properties of Kenaf Fiber Unsaturated Polyester Composites
Published in S.M. Sapuan, J. Sahari, M.R. Ishak, M.L. Sanyang, Kenaf Fibers and Composites, 2018
Md. Rezaur Rahman, Sinin Hamdan, Rubiyah bt Hj Baini
According to Coates (2000), the range for methyl C-H is 2970–2950 cm‑1 for asymmetry stretch or 2880–2860 cm‑1 for symmetry stretch. A weaker methyl or methylene band shows chain branching, and strong methyl bands indicates significant splitting (Coates 2000). As mentioned, there is carbonyl group in the composites. The carbonyl groups can be ketones, aldehydes, or esters. The carbonyl groups contain the C=O functional group. If ketones exist, the bond of C-H stretching is broader than the stretching of C-H bonds in aldehydes. From the results, the region shows the peaks at 1718.58 cm‑1 and 1720.50 cm‑1, which demonstrates that the ketones are present. However, according to Coates (2000), conjugations play as an important role when observing frequency of carbonyl. Which means the conjugations will determine that they either connect to aromatic rings or conjugate to C=C or C=O. Besides that, the level of carbonyl frequency also will help to differentiate the types of carbonyl compounds, in which it will determine if the carbonyl group will directly or indirectly attach to aromatic rings (Coates 2000).
Optical Methods of Single Molecule Detection and Applications in Biosensors
Published in George K. Knopf, Amarjeet S. Bassi, Smart Biosensor Technology, 2018
Anna Shahmuradyan, Ulrich J. Krull
Electron-donating substituents on the parent ring system lead to an increase in molar absorptivity and a shift in both the fluorescence excitation and emission spectral profiles. Electron-withdrawing substituent effects are difficult to predict and depend on, for example, whether a participating carbonyl group is an aldehyde, ketone, or carboxylic acid; whether there is aromatic character associated with the carbonyl compound; and the interaction with solvent. Nitroaromatics are usually phosphorescent, with relaxation by fluorescence often not observed due to internal conversion caused by the charge-transfer efficiency of the excited state.
Thermal Behavior and Microscopic Characteristics of Water-soaked Coal Spontaneous Combustion
Published in Combustion Science and Technology, 2022
Zhian Huang, Jinyang Li, Yukun Gao, Zhenlu Shao, Yinghua Zhang
Aliphatic hydrocarbons on the coal surface react with oxygen at low temperatures to form peroxide radicals or hydroperoxide intermediates. Hydroperoxides are decomposed into alcohols and water. The hydroxyl groups in the alcohols are oxidized and decomposed into carbonyl groups. The carbonyl is then oxidized to the carboxyl group. Aliphatic hydrocarbons reached a state of dynamic equilibrium after being soaked in water. Functional groups, such as carbonyl (C = O), generated during the oxidation of fatty groups were significantly reduced, and the content of the stable ether bonds C–O–R and C = C increased. It can be concluded that when the moisture content is low, the stability of the coal molecules is reduced and the activity is high. However, when the water content is high, coal molecules are inert, and water suppresses coal spontaneous combustion. During the dynamic reaction of functional groups on the water-soaked coal surface, 10% water content makes the coal sample reach a high molecular activity.
Synthesis and characterization of the Co(II) and Ni(II) complexes of 1,3,4-thiadiazole-derived ketones and secondary alcohols: thermal and magnetic properties
Published in Journal of Coordination Chemistry, 2021
Melih Erdogan, Kubra Kiymaz, Hakan Tahtaci, Saban Uysal
In the second step of the study, N-(5-((2-(3,4-dichlorophenyl)-2-oxoethyl)thio)-1,3,4-tiadiazole-2-yl)benzamide derivatives (5a-j) were synthesized by reaction of 3 with various benzoyl chloride derivatives (4a-j) in the presence of pyridine with yields varying between 65% and 84%. These reactions are typical nucleophilic acyl substitution reactions that occur through nucleophilic addition and elimination to the carbonyl carbon. Acyl groups produce substitution reactions, as expected. Chlorine that has bonded to the carbonyl carbon can be removed by protonation if necessary. Acyl chlorides usually react by losing the chloride ion, a very good leaving group. The lone electron pair on the amino group in 3 attacks the carbonyl carbon of the acyl derivatives (4a-j) as a nucleophile. A proton from the amino group transfers to chloride and the electron pair on oxygen attacks the carbon to form a double bond, with hydrogen chloride turning into pyridinium chloride salt. After the reaction is completed, when the raw materials formed are washed with a large amount of water, pyridinium chloride is removed from the medium. The proposed reaction mechanism for formation of 5a-j is given in Figure 2.
Purification of the Sodium Hydroxide Leaching Solution of Black Dross by Removal of Silicate(IV) with Polyacrylamide (PAM)
Published in Mineral Processing and Extractive Metallurgy Review, 2021
Thi Thuy Nhi Nguyen, Man Seung Lee
Among diverse coagulants, polyaluminum chlorides (PACl) have been extensively used in the last decades for wastewater treatment. However, chlorides can cause corrosion problems which limit the applications of PACl. In contrast, the performance of polyacrylamide (PAM) is effective in terms of cost and environmental burden (Latour, Miranda, and Blanco 2013). The amide group in the structure of PAM consists of a carbonyl group bonded to one nitrogen and two hydrogen atoms (CONH2). The carbonyl functional group is composed of a carbon atom which is double-bonded to an oxygen atom (C = O) (Uranta et al. 2018). PAM easily hydrolyzes when mixed with an alkaline solution, and its amide groups are converted into carboxylate groups (Crees, Whayman and Willersdorf 1973). Some literatures indicate that the removal of silicate by coagulation is enhanced in alkaline solution (Miranda and Latour 2015). In alkaline solution, both H3SiO4− and H2SiO42− are the predominant species of silicate. The negative charge of the silicate facilitates coagulation (Chuang et al. 2007; Sun, Laila, and Baojun 2012).