Coumarin, consumption

Additives can be consumed at the cathode by incorporation into the deposit and/or by electrochemical reaction at the cathode or anode. Consumption of coumarin in the deposition of nickel from a Watts-type solution has been studied extensively. Thus, in this section we discuss the consumption of coumarin, which is used as a leveler and partial brightener. In a series of papers (33, 36), Rogers and Taylor, described the effects of coumarin on the electrodeposition of nickel. They found that the coumarin concentration decreases linearly with time at —960 mV (versus SCE and 485 to 223 rpm at a rotating-disk electrode, for plating times of 8 to 75 min. A rotating-disk electrode was used to achieve a uniform and known rate of transport of additive to the cathode. Rogers and Taylor found that the rate of coumarin consumption is a function of coumarin bulk concentration. Figure 10.16 shows that the rate of consumption... 

Figure 10.16. Rate of coumarin consumption as a function of coumarin concentration constant-potential experiments -960 and -1125 mV versus SCE, 985 rpm, pH 4 r, theoretical rate transport. (From Ref. 33, with permission from Elsevier.)...

Incorporation of Carbon from Coumarin in Deposits. Incorporation of carbon from coumarin was studied by Rogers and Taylor (36) and Edwards and LeWett (34) using a radiotracer technique with C-labeled coumarin. They found that the consumption of coumarin by incorporation into nickel deposits is small compared with consumption by reduction reaction, by a factor of about 10. 

The preceding discussion concerning the consumption of coumarin in a Watts-type solution can serve as a model in a general discussion on the consumption of additives in electrodeposition. 

Coumarin is used as an additive in the electrodeposition of nickel from a Watts-type solution. It is reduced at the cathode, and it may be incorporated in the deposit (Section 10.8). The rate of consumption of coumarin as a function of coumarin concentration is shown in Figure 10.16. 

The coumarins were first discovered in Wisconsin, when bleeding in cattle was found to be due to the consumption of bruised sweet clover in the 1920s (1). The causative agent, dicoumarol, was isolated in 1940, and a range of related compounds was then synthesized, the most popnlar of which proved to be warfarin (named after the Wisconsin Alumni Research Foundation). Other conmarins that have been used are acenocoumarol (nicoumalone), bishydroxycoumarin, dicoumarol, ethyl biscoumacetate, and phenproconmon. 

In contrast to coumadin, coumarin is not teratogenic. In rats exposed to doses that are sufficiently high to significantly effect food consumption, coumarin can decrease reproductive success. At lower dose levels, no adverse effects on reproduction or development have been reported. 

Additives can be consumed at the cathode by incorporation into the deposit and/or by the electrochemical reaction at the cathode or anode. Consumption of coumarin... 

Murphy, S.E., L.M. Johnson, L.M. Losey S.G. Carmella, and S.S. Hecht (2001). Consumption of watercress fails to alter coumarin metabolism in humans. Drug Metab. Dispos. 29, 786-788. 

To the consumer, the most evident properties of phenolic compounds are the colors and the astringent taste they impart to foods. With few exceptions such as safrole and coumarin, most low molecular weight plant phenols have been shown to be non-toxic/non-carcinogenic in experimental animals. Further, plant phenols form a very small portion of total food intakes under normal food consumption patterns and would not be likely to have any serious toxic or antiphysiological effects. It is therefore reasonable to ask, why consider food safety of plant polyphenols Some of the reasons include ... 

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