Hydroxyl group function

A functional polymer is a polymer that contains a functional group, such as a carboxyl or hydroxyl group. Functional polymers are of interest because the functional group has a desired property or can be used to attach some moiety with the desired property [Patil et al., 1998], For example, a medication such as chloroamphenicol, a broad-spectrum antibiotic,... 

The first report on the construction of a SA multilayer appeared in 1983 [193]. A terminally bifunctional surfactant, 15-hexadecenyltrichlorosilane, was the initial building block for the formation of a SA monolayer. The trichloro-silane functionality reacted, as did OTS, with both of the hydroxyl groups on the substrate surface and with adsorbed water to form a network of Si -O-Si bonds in the SA monolayer. Conversion of the terminal double bonds to hydroxyl group functionality allowed the chemisorption of a new layer of surfactants to produce a SA bilayer (Fig. 20) [193]. The process could be repeated to form subsequent multilayers. 

Substituents other than hydroxyl groups (functional atoms or groups and hydrocarbon radicals) attached to silicon are expressed by appropriate prefixes or suffixes. Examples ... 

It is easy to project that differentiation of a higher number of hydroxyl groups (functional groups) in a polyol such as one faces in carbohydrate chemistry may... 

As recalled from our earlier discussion, we stated that if one of the reactants in step-growth polymerization has a functionality greater than 2, then the formation of a branched or a three-dimensional or cross-linked polymer is potentially possible. An example is the reaction between a dibasic acid and glycerol, which has two primary and one secondary hydroxyl groups (functionality of 3). A monomer that possesses such a functionality is referred to as a branch unit. Every reaction of such a molecule introduces a branch point for the development of the three-dimensional network. The portion of a polymer molecule lying between two branch points or a branch point and a chain end is called a chain section or segment. 

Tentagel, described above, is in wide use today in solid phase syntheses. Polyethylene glycol has also been attached to various other polymers to form support resins. For instance, Frechet and coworkers [37] used cross-linked methacrylate esters of ethylene glycol oligomers in a suspension polymerization to synthesize hydroxyl group functionalized beads. These beads swell well in a variety of polar solvents. Another example is that of Grubbs attaching a ruthenium metathesis catalyst to polyethylene [38] ... 

The functionalized macrocyclic polystyrenes (110) prepared in cyclohexane exhibited ratios of intrinsic viscosities of the cyclic to the linear polymers of 0.74 and 0.76 for polymers with M =6200 and 4000, respectively, after fractionation [255]. The hydroxyl group functionalities were determined to be 2.0, 1.9, and 2.0 for macrocyclic polystyrenes with M =4000, 6200, and 12,200, respectively [205]. The macrocycle yields were approximately 40%. 

Branched or star-block copolymers were made (187) by first polymerizing ethylene oxide onto a starter using cationic initiation. These compounds were then coupled with the diglycidyl ether of bisphenol A to increase molecular weight and to provide pendant hydroxyl group functionality in the central portions of the alkylene oxide/glycidyl epoxide copolymer. 

Recently, the application of phenoxy-imine-type vanadiirm (III) complexes 53-55 (Figure 23) for the copolymerization of ethene with polar hydroxyl group-functionalized a-olefins, such as Un-OH, 5-hexen-l-ol, and 3-butylene-l-ol, has been reported. The resulting polymers are random copolymers with a Un-OH incorporation of 13.9 mol%, molecular weights of up to 177000gmor and remarkable activities of up to... 

Some commercial polyurethane elastomers are in fact segmented copolymers prepared by reaction of a diisocyanate with a prepolymer polyol (hydroxyl group functionality 2) and a short-chain diol (e.g. butan-l,4-diol)... 

The commercial prodnction of PPC is still quite modest at several kilotous annually and its use is limited primarily to binder applications in ceramic sintering processes where it benefits from a lower decomposition temperature compared to other binders [25]. More recently developed cobalt salem catalysts [26] and proprietary catalysts with improved activity and selectivity are able to prodnce tailored PPC polyols with specific molecular weights and hydroxyl group functionalities [27,28]. The polyurethanes synthesized from these polyols are reported to exhibit increased strength and durability caused by the polycarbonate backbone [29]. Besides C02-based PPC, other poly(alkylene carbonate)s are produced in pilot-scale processes [27]. 

The most difflcult pharmaceutically relevant oxidation of steroids is the introduction of a 14 -hydroxyl group. This functional group is found in heart-active steroids (cardenolides) such as digitoxigenin, which also contain a 17/J-butenolide substituent. The 14/ -hydroxyl group is easily cleaved off by dehydration and must therefore not be treated with Lewis or... 

Functional class names of alcohols are derived by naming the alkyl group that bears the hydroxyl substituent (—OH) and then adding alcohol as a separate word The chain IS always numbered beginning at the carbon to which the hydroxyl group is attached... 

Hydroxyl groups however outrank the double bond Compounds that contain both a double bond and a hydroxyl group use the combined suffix en + ol to signify that both functional groups are present... 

Notice that the carboxyl group that stays behind during the decarboxylation of mal onic acid has a hydroxyl function that is not directly involved m the process Compounds that have substituents other than hydroxyl groups at this position undergo an analogous decarboxylation... 

In keeping with its biogenetic origin m three molecules of acetic acid mevalonic acid has six carbon atoms The conversion of mevalonate to isopentenyl pyrophosphate involves loss of the extra carbon as carbon dioxide First the alcohol hydroxyl groups of mevalonate are converted to phosphate ester functions—they are enzymatically phosphorylated with introduction of a simple phosphate at the tertiary site and a pyrophosphate at the primary site Decarboxylation m concert with loss of the terti ary phosphate introduces a carbon-carbon double bond and gives isopentenyl pyrophos phate the fundamental building block for formation of isoprenoid natural products... 

Fig. 5.16 Surface concentration of hydroxyl groups of silica, as a function of the temperature of dehydration. Data are +, from Fripiat and Uytterhoeven A, from Kiselev and Zhuralev O, from Taylor (cf.

Oxidation. Oxidation of hydroxybenzaldehydes can result in the formation of a variety of compounds, depending on the reagents and conditions used. Replacement of the aldehyde function by a hydroxyl group results when 2- or 4-hydroxybenzaldehydes are treated with hydrogen peroxide in acidic (42) or basic (43) media pyrocatechol or hydroquinone are obtained, respectively. 

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