Biodegradable ester

Table 6.1 Gathergood et al. [16] linked biodegradable ester chains to an inert cationic core. 

Ester oils have a high thermal resistance and excellent low-temperature behaviour [69]. Rapidly biodegradable ester oils will gain importance in industrial applications because it is possible to achieve the same efficiency as for polyglycol oils by selecting an appropriate ester base oil. However, certain ester oils may exhibit low hydrolytic stability. 

Compounds 251a to 251f, 252 to 256, 257a-257b, 258, 259, 262 and 263 were tested for antibacterial activity, as the biodegradable esters (R = CH20C0tBu) [135] or the acids (R = H). They are inactive against... 

Lim et al. [114] synthesized a biodegradable ester analog of polylysine, poly[alpha-(4-aminobutyl)-L-glycolic acid] (PAGA). While the polymer displayed no cytotoxicity, only modest transfection activity was observed. This maybe due to a too fast hydrolysis and, similar to polylysine, the lack of efficient endosomal escape functionality. Another biodegradable cationic polyester, poly (4-hydroxy-L-proline ester) showed similar characteristics [115]. 

A number of plasticizers have been investigated for potential use in biodegradable polymers. Favorable compounds are citrate plasticizers. These are biodegradable esters. 

Starch/Biodegradable Esters Blends, Polym. Prepr, 41, 64-65... 

Esters generally tend to be readily biodegradable. This is advantageous for two-cycle engine oils which are discharged to the surroundings from power-driven recreational boats and various portable power units around the home. 

The threat of accidental misuse of quaternary ammonium compounds coupled with potential harmful effects to sensitive species of fish and invertebrates has prompted some concern. Industry has responded with an effort to replace the questionable compounds with those of a more environmentally friendly nature. Newer classes of quaternaries, eg, esters (206) and betaine esters (207), have been developed. These materials are more readily biodegraded. The mechanisms of antimicrobial activity and hydrolysis of these compounds have been studied (207). AppHcations as surface disinfectants, antimicrobials, and in vitro microbiocidals have also been reported. Examples of ester-type quaternaries are shown in Figure 1. 

In 1991, the European fabric softener market took a sharp turn. Producers in Germany, the Netherlands, and later in Austria and Switzerland voluntarily gave up the use of DHTDMAC (238) because of pressure from local environmental authorities, who gave an environmentally hazardous classification to DHTDMAC. A number of esterquats were developed as candidates to become successors to DHTDMAC (see Fig. 1). The ester group facihtates biodegradation. 

Pig. 14. Preparation of biodegradable PS by incorporating ester linkages into the backbone via ring-opening copolymerization of styrene with a cycHc ketene... 

Sucrose reacts with fatty acids to produce esters with degrees of esterification (DE) from 1 to 8 and hydrophi1 ic /Iipophi1 ic balances that provide them with numerous appHcations. Primary producers are Japan and the Netherlands, with total production at 6000 t/yr. Sucrose esters are nontoxic and biodegradable, and are approved for use in the EC, Japan, and the United States. 

Nontoxic ahphatic compounds containing carboxyl, ester, or hydroxyl groups are readily biodegradable. Those with dicarboxyhc groups require longer acclimation times than those with a single carboxyl group. 

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