المنتديات العلمية
منتدى علم الكيمياء => منتدى علم الكيمياء => الموضوع حرر بواسطة: عين المستقبل في يونيو 09, 2008, 11:37:39 صباحاً
-
بسم الله الرحمن الرحيم
يسرني أن أضع بين يدي زملائي خطوات تحضير المركب benzoylglycin أملا الإستفادة وشكرا
Preparation of Benzoylglycine ( hippuric acid )
*Requirements:
-glycine ,Sodium hydroxide, benzoyl Chloride, water, crushed ice ,concentrated hydrochloric acid ,carbon tetrachloride, charcoal ,Congo red.
-conical flask ,beaker, Stirring ,Buchner Funnel , Funnel. Watch glass, Oven.
*Procedures:
1- Dissolve 6.25g of glycine in 25ml of 10 per cent sodium hydroxide solution contained in conical flask (250 ml).
2- Add 11.25 ml of benzoyl chloride in five portions to the solution , stopper the vessel and shake vigorously after each addition until all the chloride has reacted.
3- Transfer the solution to a beaker and rinse the conical flask with a little water.
4-Place a few grams of crushed ice in the solution and add concentrated hydrochloric acid slowly and with stirring until the mixture is acid to cong red paper .
5- Collect the resulting crystalline precipitate of benzoylglycine , which is contaminated with a little benzoic acid, upon abuchner funnel , wash with cold water and drain well.
6- place the solid in a beaker with 25 ml of carbon tetra chloride, cover the beaker with a watch glass and boil gently for 10minutes (fume cupboard) ,this extracts any benzoic acid which may be present.
7-Allow the mixture to cool slightly , filter under gentle suction and wash the product on the filter with 10 ml of carbon tetrachloride.
8-Recrystallise the dried product from boiling water (about 125 ml ) with the addition of a little decolourising charcoal if necessary, filter through a hot water funnel and allow to crystallize.
9-Collect the benzoylglycine in a Buchner funnel and dry it in an oven .
The yield is 11.25 g (76%)
M.p =187Cْ
مع خالص التحية والتقدير
المرجع معمل كلية العلوم جامعة تعز اليمن
-
السلام عليكم ورحمة الله وبركااته..
الأخ الكريم " عبـده الصلاحي "..
أهلاً وسهلاً بك معنا في المنتديات العلمية وفي قسم الكيمياء..
شكراً على الموضوع الجميل ونحن بانتظار المزيد منك والمميز بإذن الله..
مع جزيل الشكر والتقدير
أختك/ شرشبيــل
-
الأخت شرشبيل
شكرا على المرور والتوقيع
وللجميع
أمنيات السعادة الدائمة
ش,
ك,
ر,اااا