Functionalization hydrocarbon group

Collectors ndFrothers. Collectors play a critical role ia flotation (41). These are heteropolar organic molecules characterized by a polar functional group that has a high affinity for the desired mineral, and a hydrocarbon group, usually a simple 2—18 carbon atom hydrocarbon chain, that imparts hydrophobicity to the minerals surface after the molecule has adsorbed. Most collectors are weak acids or bases or their salts, and are either ionic or neutral. The mode of iateraction between the functional group and the mineral surface may iavolve a chemical reaction, for example, chemisorption, or a physical iateraction such as electrostatic attraction. 

The functional group ia collectors for nonsulfide minerals is characterized by the presence of either a N (amines) or an O (carboxyUc acids, sulfonates, etc) as the donor atoms. In addition to these, straight hydrocarbons, such as fuel oil, diesel, kerosene, etc, are also used extensively either as auxiUary or secondary collectors, or as primary collectors for coal and molybdenite flotation. The chain length of the hydrocarbon group is generally short (2—8 C) for the sulfide collectors, and long (10—20 C) for nonsulfide collectors, because sulfides are generally more hydrophobic than most nonsulfide minerals (10). 

For functional compounds, eg alcohols. The assumption is made that the contributions of hydrocarbon groups are the same as in the previous compounds except for groups directly linked to hydroxyl. 

The concept of a group is especially important in organic chemistry. A functional group represents a set of atoms that is closely linked with chemical reactivity and defined classes of substances. For instance, the functional group hydroxyl, -OH, is characteristic of the classes alcohol, phenol and enol. Alcohols are often represented by the general formula R-OH, in which R- represents a hydrocarbon group typical of aliphatic and alicyclic substances. 

Let us start out by a few comments about the terms used to describe carbon skeletons encountered in organic molecules. When considering a hydrocarbon (i.e., a compound consisting of only C and H) or a hydrocarbon group (i.e., a hydrocarbon substituent) in a molecule, the only possible functionalities are carbon-carbon double and triple bonds. A carbon skeleton is said to be saturated if it has no double or triple bond, and unsaturated if there is at least one such bond present. Hence, in a hydrocarbon, the term saturated indicates that the carbon skeleton contains the maximum number of hydrogen atoms compatible with the requirement that carbon always forms four bonds and hydrogen one. A saturated carbon atom is one that is singly bound to four other separate atoms. 

Yet another way to minimize the number of parameters required is to adopt a so-called united-atom (UA) model. That is, instead of defining only atoms as the fundamental units of the force field, one also defines certain functional groups, usually hydrocarbon groups, e.g., methyl, methylene, aryl CH, etc. The group has its own single set of non-bonded and other parameters - effectively, this reduces the total number of atoms by one less than the total number incorporated into the united atom group. 

Myrdal, P., et al AQUAFAC 1 Aqueous Function of group Activity Coefficients Application to Hydrocarbons. Chemosphere, 1992 24, 1047-1061. 

Adsorption Using data from Table 5.1 Adsorption of organic compounds on the metal surface under static conditions and on the nascent steel surfaces , discuss the adsorption activity for each of the following (a) saturated hydrocarbons (n-hexane, cyclohexane), (b) the compounds which have rr-electrons (benzene, 1-hexene), (c) compounds with functional polar groups (propylamine, propionic acid). 

Most nonpolar (e g., hydrocarbon) groups are in the interior of the molecule, thus avoiding thermodynamically unfavorable contact with water. Exceptions to this may function as specific binding sites on the surface of the molecule for other proteins or ligands. 

The Ziegler-Natta polymerization of ethylene can be adapted to make molecules of only modest size (C6--C20) and containing certain functional groups. If, for example, the mctal-alkyls initially obtained are heated (in the presence of ethylene and a nickel catalyst), the hydrocarbon groups are displaced as straight-chain 1-alkenes of even carbon number. Large quantities of such alkenes in the C12-C20 range are... 

R can be a hydrogen atom or a hydrocarbon group. An aldehydes functional group is usually represented by -CHO in condensed formulas. The simplest aldehyde is Web... 

---