{"id":100,"date":"2018-05-04T14:37:03","date_gmt":"2018-05-04T13:37:03","guid":{"rendered":"http:\/\/cursolusegil.webs.upv.es\/?p=100"},"modified":"2019-04-15T14:49:33","modified_gmt":"2019-04-15T13:49:33","slug":"formas-de-cristalizar","status":"publish","type":"post","link":"https:\/\/cursolusegil.blogs.upv.es\/?p=100","title":{"rendered":"FORMAS DE CRISTALIZAR"},"content":{"rendered":"<p>Para cristalizar se necesita <strong>sobresaturar<\/strong> la disoluci\u00f3n, lo cual implica obtener una disoluci\u00f3n con una concentraci\u00f3n de solutos mayor a la que viene dada por su equilibrio termodin\u00e1mico, es decir, por su curva de saturaci\u00f3n.<\/p>\n<p>Existen diferentes formas de alcanzar la sobresaturaci\u00f3n:<\/p>\n<ul>\n<li><strong>Por concentraci\u00f3n.<\/strong><\/li>\n<li><strong>Por enfriamiento.<\/strong><\/li>\n<li><strong>Por reacci\u00f3n o desplazamiento del equilibrio.<\/strong><\/li>\n<\/ul>\n<p>Si la solubilidad del soluto <strong>aumenta fuertemente con la temperatura<\/strong>, como ocurre frecuentemente con muchas sales inorg\u00e1nicas y sustancias org\u00e1nicas, una soluci\u00f3n saturada se transforma en sobresaturada disminuyendo la temperatura por <strong>enfriamiento<\/strong>. Si la solubilidad es relativamente <strong>independiente de la temperatura<\/strong> como en el caso de sal com\u00fan, la sobresaturaci\u00f3n se puede conseguir\u00a0<strong>evaporando<\/strong>\u00a0parte del disolvente. Por \u00faltimo, si la solubilidad es muy elevada estos m\u00e9todos pueden no resultar adecuados, por lo que se recurre a a\u00f1adir un tercer componente,\u00a0lo que se conoce como cristalizaci\u00f3n por reacci\u00f3n o desplazamiento del equilibrio. El tercer componente puede actuar f\u00edsicamente dando lugar a una mezcla con el disolvente original en la que la solubilidad del soluto disminuye bruscamente, o bien se puede crear qu\u00edmicamente un nuevo soluto a\u00f1adiendo un tercer componente que reaccione con el soluto original para formar una sustancia insoluble. En determinados casos, se combinan ambos procesos (evaporaci\u00f3n y enfriamiento) para conseguir la sobresaturaci\u00f3n necesaria.<\/p>\n<p>A continuaci\u00f3n se muestra c\u00f3mo alcanzar la sobresaturaci\u00f3n sobre curvas de solubilidad de (A. izquierda) compuestos cuya solubilidad var\u00eda significativamente con la temperatura y (B. derecha) compuestos cuya solubilidad no var\u00eda significativamente con la temperatura. Para los primeros, el enfriamiento es una buena forma de conseguir la sobresaturaci\u00f3n, mientras que para cristalizar los segundos es necesario concentrar la disoluci\u00f3n.<\/p>\n<div id='gallery-1' class='gallery galleryid-100 gallery-columns-2 gallery-size-medium'><figure class='gallery-item'>\n\t\t\t<div class='gallery-icon landscape'>\n\t\t\t\t<a href='https:\/\/cursolusegil.blogs.upv.es\/?attachment_id=124'><img loading=\"lazy\" decoding=\"async\" width=\"300\" height=\"191\" src=\"https:\/\/cursolusegil.blogs.upv.es\/wp-content\/uploads\/2018\/05\/Cristalizaci\u00f3n-enfriamiento-300x191.jpg\" class=\"attachment-medium size-medium\" alt=\"\" srcset=\"https:\/\/cursolusegil.blogs.upv.es\/wp-content\/uploads\/2018\/05\/Cristalizaci\u00f3n-enfriamiento-300x191.jpg 300w, https:\/\/cursolusegil.blogs.upv.es\/wp-content\/uploads\/2018\/05\/Cristalizaci\u00f3n-enfriamiento.jpg 416w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a>\n\t\t\t<\/div><\/figure><figure class='gallery-item'>\n\t\t\t<div class='gallery-icon landscape'>\n\t\t\t\t<a href='https:\/\/cursolusegil.blogs.upv.es\/?attachment_id=127'><img loading=\"lazy\" decoding=\"async\" width=\"300\" height=\"191\" src=\"https:\/\/cursolusegil.blogs.upv.es\/wp-content\/uploads\/2018\/05\/Cristalizaci\u00f3n-evaporaci\u00f3n-300x191.jpg\" class=\"attachment-medium size-medium\" alt=\"\" srcset=\"https:\/\/cursolusegil.blogs.upv.es\/wp-content\/uploads\/2018\/05\/Cristalizaci\u00f3n-evaporaci\u00f3n-300x191.jpg 300w, https:\/\/cursolusegil.blogs.upv.es\/wp-content\/uploads\/2018\/05\/Cristalizaci\u00f3n-evaporaci\u00f3n.jpg 416w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a>\n\t\t\t<\/div><\/figure>\n\t\t<\/div>\n\n<p>En cualquier caso,\u00a0<strong>la fuerza impulsora del proceso de cristalizaci\u00f3n es la sobresaturaci\u00f3n,<\/strong> de forma que tanto la <strong>nucleaci\u00f3n<\/strong> como el <strong>crecimiento del cristal<\/strong> se dar\u00e1n \u00fanicamente si la disoluci\u00f3n est\u00e1 sobresaturada.<\/p>\n<h1>CRISTALLIZATION PROCESSES<\/h1>\n<p>Crystallization can only take place when a solution is <strong>supersaturated<\/strong>, which implies obtaining a solution with a concentration higher than the given by its thermodynamic equilibrium, that is, the given by its saturation or solubility curve.<\/p>\n<p>There are different ways of <strong>supersaturating a<\/strong> solution:<\/p>\n<ul>\n<li><strong>Concentration<\/strong><\/li>\n<li><strong>Cooling<\/strong><\/li>\n<li><strong>Reaction or equilibrium displacement<\/strong><\/li>\n<\/ul>\n<p>If solubility <strong>significantly depends on temperature<\/strong>, as occurs with some inorganic salts and organic substances, a saturated solution transforms into a supersaturated one by <strong>cooling<\/strong>. In contrast, if solubility is rather <strong>temperature independent<\/strong>, as in the case of NaCl, supersaturation is better achieved by <strong>evaporating<\/strong> part of the solvent. In most cases, both cooling and concnetration are combined to obtain the desired supersaturation. Finally, if solubility is significantly high these methods may not be adequate, for which it is common to modify the component solubility by adding a third compound, this procedure is known as crystallization by reaction or equlibrium displacement. The third component may act physically by creating a mixture with the original solvent, i which the solute solubility decreases dramatically, or either chemically creating a new solute which solubility in the original solvent is very low.<\/p>\n<p>Next, the ways in which supersaturation may be reached on different solubility curves\/lines are shown: (A. left) Solutes which solubility significantly varies with temperature and (B. right) compounds which solubility does not significantly vary with temperature. For the former, cooling is a good way of reaching supersaturation, whereas the latter require concentration by solvent removal.<\/p>\n<div id='gallery-2' class='gallery galleryid-100 gallery-columns-2 gallery-size-medium'><figure class='gallery-item'>\n\t\t\t<div class='gallery-icon landscape'>\n\t\t\t\t<a href='https:\/\/cursolusegil.blogs.upv.es\/?attachment_id=124'><img loading=\"lazy\" decoding=\"async\" width=\"300\" height=\"191\" src=\"https:\/\/cursolusegil.blogs.upv.es\/wp-content\/uploads\/2018\/05\/Cristalizaci\u00f3n-enfriamiento-300x191.jpg\" class=\"attachment-medium size-medium\" alt=\"\" srcset=\"https:\/\/cursolusegil.blogs.upv.es\/wp-content\/uploads\/2018\/05\/Cristalizaci\u00f3n-enfriamiento-300x191.jpg 300w, https:\/\/cursolusegil.blogs.upv.es\/wp-content\/uploads\/2018\/05\/Cristalizaci\u00f3n-enfriamiento.jpg 416w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a>\n\t\t\t<\/div><\/figure><figure class='gallery-item'>\n\t\t\t<div class='gallery-icon landscape'>\n\t\t\t\t<a href='https:\/\/cursolusegil.blogs.upv.es\/?attachment_id=127'><img loading=\"lazy\" decoding=\"async\" width=\"300\" height=\"191\" src=\"https:\/\/cursolusegil.blogs.upv.es\/wp-content\/uploads\/2018\/05\/Cristalizaci\u00f3n-evaporaci\u00f3n-300x191.jpg\" class=\"attachment-medium size-medium\" alt=\"\" srcset=\"https:\/\/cursolusegil.blogs.upv.es\/wp-content\/uploads\/2018\/05\/Cristalizaci\u00f3n-evaporaci\u00f3n-300x191.jpg 300w, https:\/\/cursolusegil.blogs.upv.es\/wp-content\/uploads\/2018\/05\/Cristalizaci\u00f3n-evaporaci\u00f3n.jpg 416w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a>\n\t\t\t<\/div><\/figure>\n\t\t<\/div>\n\n<p>In any case, <strong>supersaturation is the driving force for crystallization<\/strong>, so that both <strong>nucleation<\/strong> and <strong>crystal growth<\/strong> can only take place when the solution is supersaturated.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Para cristalizar se necesita sobresaturar la disoluci\u00f3n, lo cual implica obtener una disoluci\u00f3n con una concentraci\u00f3n de solutos mayor a la que viene dada por su equilibrio termodin\u00e1mico, es decir, por su curva de saturaci\u00f3n. Existen diferentes formas de alcanzar la sobresaturaci\u00f3n: Por concentraci\u00f3n. Por enfriamiento. Por reacci\u00f3n o desplazamiento del equilibrio. Si la solubilidad &hellip; <a href=\"https:\/\/cursolusegil.blogs.upv.es\/?p=100\" class=\"more-link\">Seguir leyendo <span class=\"screen-reader-text\">FORMAS DE CRISTALIZAR<\/span> <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":831,"featured_media":342,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1020522,1024152],"tags":[1021781,1022246,1022029,1021493,1021168],"class_list":["post-100","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-conceptos-teoricos","category-cristalizacion","tag-curvas-de-solubilidad","tag-formas-de-cristalizar","tag-formas-de-sobresaturar","tag-nucleacion-y-crecimiento","tag-teoria-de-cristalizacion"],"_links":{"self":[{"href":"https:\/\/cursolusegil.blogs.upv.es\/index.php?rest_route=\/wp\/v2\/posts\/100","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/cursolusegil.blogs.upv.es\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/cursolusegil.blogs.upv.es\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/cursolusegil.blogs.upv.es\/index.php?rest_route=\/wp\/v2\/users\/831"}],"replies":[{"embeddable":true,"href":"https:\/\/cursolusegil.blogs.upv.es\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=100"}],"version-history":[{"count":0,"href":"https:\/\/cursolusegil.blogs.upv.es\/index.php?rest_route=\/wp\/v2\/posts\/100\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/cursolusegil.blogs.upv.es\/index.php?rest_route=\/wp\/v2\/media\/342"}],"wp:attachment":[{"href":"https:\/\/cursolusegil.blogs.upv.es\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=100"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/cursolusegil.blogs.upv.es\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=100"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/cursolusegil.blogs.upv.es\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=100"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}