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Contribución de las microondas en el desarrollo de la química verde ...

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A B S T R A C<br />

The microwaves like way of <strong>en</strong>ergizing chemical reactions it has had a great acceptance on the part of<br />

very much sci<strong>en</strong>tific groups in the whole world. In our school the group led by the Dr. Eloy Vazquez<br />

Labastida has come being employed in the <strong><strong>la</strong>s</strong>t 6 years at this area with exc<strong>el</strong>l<strong>en</strong>t results. For those who<br />

in this work are summarized and they analyze many of the sci<strong>en</strong>tific information that have led to this<br />

technology to the lev<strong>el</strong>s that the <strong>en</strong>vironm<strong>en</strong>t has, the most important advances are outlined, focusing the<br />

work in the s<strong>en</strong>se of knowing and analyzing the converg<strong>en</strong>ce betwe<strong>en</strong> this tannic and the new<br />

technology.<br />

The ov<strong>en</strong> of domestic microwave is an inv<strong>en</strong>tion coinci<strong>de</strong>ncial, as many of that they have appeared along<br />

the history of the man. The one who was going to think that the fact happ<strong>en</strong>ed to Percy Sp<strong>en</strong>cer who was<br />

working for a manufacturing p<strong>la</strong>nt of radars during 2 ª world war, would provi<strong>de</strong> to him the information that<br />

would take him to the <strong>de</strong>v<strong>el</strong>opm<strong>en</strong>t of this type of instrum<strong>en</strong>tation wh<strong>en</strong> he noticed of the heat build-up in<br />

an ant<strong>en</strong>na of radar. In 1947 the first commercial unit appeared on the market for the food transformation.<br />

The first ov<strong>en</strong> of domestic microwave of which knowledge is had was pres<strong>en</strong>ted by the old north American<br />

company of domestic appliances Tappan-IEM in the year of 1955. Nowadays the sale of domestic<br />

economic ov<strong>en</strong>s and his use they repres<strong>en</strong>t an annual multimillionaire market, neverth<strong>el</strong>ess we must not<br />

confuse these articles with the new g<strong>en</strong>eration of companies <strong>de</strong>dicated to the manufacture of specific<br />

equipm<strong>en</strong>ts for investigation where the temperature and the pressure can be perfectly controlled.<br />

Numerous applications using the microwaves as way <strong>en</strong>ergizante they have appeared in <strong><strong>la</strong>s</strong>t two<br />

<strong>de</strong>ca<strong>de</strong>s principally for the dried one of differ<strong>en</strong>t types of materials (rubbers, tobacco, leather, sugar,<br />

coffee, grains, etc ...), in processes and treatm<strong>en</strong>t of e<strong><strong>la</strong>s</strong>tomers, vulcanization, extraction, polymerization,<br />

synthesis of medicam<strong>en</strong>ts and raw materials, besi<strong>de</strong>s his wi<strong>de</strong> acceptance in the food processing industry<br />

and of process. The fi<strong>el</strong>d of the organic chemistry repres<strong>en</strong>ted with microwave, it is therefore a technology<br />

practically young woman. The first two publications, consi<strong>de</strong>red pioneers of the fi<strong>el</strong>d appeared in 1986 and<br />

they are attributed to the investigators R. Gedye and R. J. Giguere. These authors <strong>de</strong>scribed that several<br />

reactions in the organic chemistry that they were needing of a lot of time un<strong>de</strong>r traditional warming<br />

(burners, baths of oil, b<strong>la</strong>nkets of warming, etc. …) they were conclu<strong>de</strong>d in very short times using<br />

microwave (MW), as way of warming in only a few minutes and ev<strong>en</strong> seconds, wh<strong>en</strong> they were p<strong>la</strong>ced in<br />

closed containers (g<strong><strong>la</strong>s</strong>s, quartz or teflón) in domestic ov<strong>en</strong>s.<br />

If the viability of the procedure was evi<strong>de</strong>nt, some explosions caused by the rapid <strong>de</strong>v<strong>el</strong>opm<strong>en</strong>t of<br />

discharges pressures g<strong>en</strong>erated insi<strong>de</strong> the systems of reaction <strong>de</strong>monstrated, for what they were the<br />

principal aim of the first experi<strong>en</strong>ces brought in the sci<strong>en</strong>tific literature for multiple authors.<br />

The first brought experi<strong>en</strong>ces were directed the prev<strong>en</strong>tion of the above m<strong>en</strong>tioned disadvantages and<br />

surer technologies were looked using equipm<strong>en</strong>ts like that of reaction more sure with op<strong>en</strong>ed <strong>de</strong>vices,<br />

using solv<strong>en</strong>ts, up to coming to the new options of reactions without solv<strong>en</strong>t or in inert supports taking the<br />

technology towards the area of the called " Gre<strong>en</strong> Chemistry ". This procedure has showed interest in free<br />

reactions of solv<strong>en</strong>t, is a more economic technology of rapid acc<strong>el</strong>eration in the speed of the reaction and<br />

without the g<strong>en</strong>eration of secondary reactions or pollutant garbage.<br />

The aim of this work is to c<strong>en</strong>tre on the diverse fi<strong>el</strong>ds of the use of this new technology and on the<br />

principal fi<strong>el</strong>ds of the organic synthesis, trying to interpret by means of the analysis of the works that have<br />

appeared, to c<strong>la</strong>rify not only the thermal ph<strong>en</strong>om<strong>en</strong>on of the process, but also, since there are affected the<br />

speed and the <strong>en</strong>ergy of the reaction.<br />

II

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