{"id":3327,"date":"2022-06-07T06:56:36","date_gmt":"2022-06-07T04:56:36","guid":{"rendered":"https:\/\/toulouse-sgencfdt.fr\/WORDPRESS_ITRF\/?p=3327"},"modified":"2022-06-07T06:56:36","modified_gmt":"2022-06-07T04:56:36","slug":"synthese-acide-benzoique","status":"publish","type":"post","link":"https:\/\/toulouse-sgencfdt.fr\/WORDPRESS_ITRF\/2022\/06\/07\/synthese-acide-benzoique\/","title":{"rendered":"synth\u00e8se acide benzoique"},"content":{"rendered":"ac benzoique<\/a> \"\"<\/a><\/p>\n

 <\/p>\n

Il faut faire un tableau d\u2019avancement apr\u00e8s avoir calcul\u00e9 les quantit\u00e9s de mati\u00e8re de chaque r\u00e9actif\u00a0:<\/span><\/span><\/p>\n

On a V<\/span>a<\/span><\/sub> = 10,0 mL d\u2019alcool benzylique de densit\u00e9 d = 1,04, de masse molaire 108 g.mol<\/span>-1<\/span><\/sup>, et m<\/span>p<\/span><\/sub> = 22,5 g de permanganate de potassium de masse molaire M(KMnO<\/span>4<\/span><\/sub>) = 158 g.mol<\/span>-1<\/span><\/sup>.<\/span><\/span><\/p>\n

Alcool benzylique\u00a0:<\/u><\/span> , <\/span> et <\/span> => <\/span>\uf072<\/span>a<\/span><\/sub> = d.<\/span>\uf072<\/span>eau<\/span><\/sub> et m<\/span>a<\/span><\/sub> = <\/span>\uf072<\/span>a<\/span><\/sub>.V<\/span>a<\/span><\/sub> => m<\/span>a<\/span><\/sub> = d.<\/span>\uf072<\/span>eau<\/span><\/sub>.V<\/span>a<\/span><\/sub><\/span><\/p>\n

Donc\u00a0: <\/span> => <\/span><\/span> => n<\/span><\/span>a<\/span><\/span><\/sub> = 9,63.10<\/span><\/span>-2<\/span><\/span><\/sup> mol<\/span><\/span><\/span><\/p>\n

Permanganate de potassium\u00a0:<\/u><\/span> , donc\u00a0: <\/span> => n<\/span>p<\/span><\/sub> = 1,42.10<\/span>-1<\/span><\/sup> mol<\/span><\/span><\/p>\n

R\u00e9actif limitant\u00a0:<\/span><\/span><\/p>\n

Alcool benzylique\u00a0: 9,63.10<\/span>-2<\/span><\/sup> \u2013 3x<\/span>max<\/span><\/sub> = 0 => x<\/span>max<\/span><\/sub> = 3,21.10<\/span>-2<\/span><\/sup> mol<\/span><\/span><\/p>\n

Permanganate de potassium\u00a0: 1,42.10<\/span>-1<\/span><\/sup> \u2013 4x<\/span>max<\/span><\/sub> = 0 => x<\/span>max<\/span><\/sub> = 3,56.10<\/span>-2<\/span><\/sup> mol<\/span><\/span><\/p>\n

Le r\u00e9actif limitant est l\u2019alcool benzylique, donc le permanganate de potassium est en exc\u00e8s.<\/span><\/span><\/p>\n

La solubilit\u00e9 de l\u2019acide benzo\u00efque d\u00e9pend de la temp\u00e9rature\u00a0: \u00e0 95 \u00b0C, la solubilit\u00e9 est de 68g.L<\/span>-1<\/span><\/sup>, alors qu\u2019\u00e0 20 \u00b0C, elle est de 3,4 g.L<\/span>-1<\/span><\/sup>. La <\/span><\/span>glace permet d\u2019abaisser la temp\u00e9rature de la solution afin que l\u2019acide benzo\u00efque soit tr\u00e8s peu soluble dans l\u2019eau et pr\u00e9cipite.<\/span><\/p>\n

Pour s\u00e9cher l\u2019acide benzo\u00efque, il faut \u00e9liminer l\u2019eau pr\u00e9sente, mais ne pas faire fondre l\u2019acide benzo\u00efque, ni trop le solubiliser. Celui-ci a une temp\u00e9rature de fusion de 122 \u00b0C. Il faut chauffer autour de 70 \u00b0C.<\/span><\/span><\/p>\n

On a Rf=1,7\/3,5=0,49<\/span><\/p>\n

le rendement:\u00a0<\/span><\/p>\n

TP1 : m<\/span>exp\u00e9rimental<\/span><\/span>\u00a0= 1,80 g et m<\/span>th\u00e9orique<\/span><\/span>\u00a0= 5,85 g =>\u00a0<\/span>=>\u00a0<\/span>\uf068<\/span>\u00a0= 30,8 %<\/span><\/span><\/p>\n

TP 2 : m<\/span>exp\u00e9rimental<\/span><\/span>\u00a0= 4,07 g et m<\/span>th\u00e9orique<\/span><\/span>\u00a0= 11,7 g =>\u00a0<\/span>=>\u00a0<\/span>\uf068<\/span>\u00a0= 34,8 %<\/span><\/span><\/p>\n","protected":false},"excerpt":{"rendered":"

  Il faut faire un tableau d\u2019avancement apr\u00e8s avoir calcul\u00e9 les quantit\u00e9s de mati\u00e8re de chaque r\u00e9actif\u00a0: On a Va = 10,0 mL d\u2019alcool benzylique de densit\u00e9 d = 1,04, de masse molaire 108 g.mol-1, et mp = 22,5 g de permanganate de potassium de masse molaire M(KMnO4) = 158 g.mol-1. Alcool benzylique\u00a0: , et … Continuer la lecture de synth\u00e8se acide benzoique<\/span> →<\/span><\/a><\/p>\n","protected":false},"author":11,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-3327","post","type-post","status-publish","format-standard","hentry","category-non-classe"],"_links":{"self":[{"href":"https:\/\/toulouse-sgencfdt.fr\/WORDPRESS_ITRF\/wp-json\/wp\/v2\/posts\/3327","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/toulouse-sgencfdt.fr\/WORDPRESS_ITRF\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/toulouse-sgencfdt.fr\/WORDPRESS_ITRF\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/toulouse-sgencfdt.fr\/WORDPRESS_ITRF\/wp-json\/wp\/v2\/users\/11"}],"replies":[{"embeddable":true,"href":"https:\/\/toulouse-sgencfdt.fr\/WORDPRESS_ITRF\/wp-json\/wp\/v2\/comments?post=3327"}],"version-history":[{"count":2,"href":"https:\/\/toulouse-sgencfdt.fr\/WORDPRESS_ITRF\/wp-json\/wp\/v2\/posts\/3327\/revisions"}],"predecessor-version":[{"id":3330,"href":"https:\/\/toulouse-sgencfdt.fr\/WORDPRESS_ITRF\/wp-json\/wp\/v2\/posts\/3327\/revisions\/3330"}],"wp:attachment":[{"href":"https:\/\/toulouse-sgencfdt.fr\/WORDPRESS_ITRF\/wp-json\/wp\/v2\/media?parent=3327"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/toulouse-sgencfdt.fr\/WORDPRESS_ITRF\/wp-json\/wp\/v2\/categories?post=3327"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/toulouse-sgencfdt.fr\/WORDPRESS_ITRF\/wp-json\/wp\/v2\/tags?post=3327"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}