on a C-C backbone tends to resist degradation‚ whereas heteroatom-containing polymer backbones confer biodegradability. Biodegradability can‚ therefore‚ be engineered into polymers by the judicious addition of chemical linkages such as anhydride‚ ester‚ or amide bonds‚ among others. The usual mechanism for degradation is by hydrolysis or enzymatic cleavage of the labile heteroatom bonds‚ resulting in a scission of the polymer backbone. Macroorganisms can eat and‚ sometimes‚ digest polymers‚ and also
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What does August Wilson use the symbols a chain link‚ bucket of nails and two pennies to represent throughout his play Gem of the Ocean? In August Wilson’s play Gem of the Ocean he uses a lot of items and as well as characters to symbolize many things. In the play Gem of the ocean August Wilson uses the chain link to symbolize good luck‚ a bucket of nails to symbolize freedom and two pennies to symbolize hope and/or passage. Throughout the course of August Wilson’s life‚ he wrote a total sixteen
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Acid and Potentiometric Determination of its Purity and Dissociation Constant ------------------------------------------------- Abstract The purpose of the study is to synthesize salicylic acid from the ester‚ methyl salicylate‚ and determine the acid’s dissociation constant and purity. The ester was converted to salicylic acid by base hydrolysis. The products were refluxed and recrystallized‚ to ensure maximum purity‚ and filtered‚ dried‚ and weighed. The melting point of the product was determined
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Pinnata seed oil is obtained after the mechanical extraction of rubber seed is using Soxhlet Extractor. The alcohol used in this research is methanol which is used to react with Pongomia Pinnata seed oil with a base or acid catalyst to produce methyl ester. Acid catalyst used in this research is potassium hydroxide (KOH) and base catalyst used is sodium hydroxide (NAOH). Parameter that concerned in this research is temperature and the ratio of alcohol and Pongomia Pinnata seed oil introduced in the microwave
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Aaron Papp Dr. Bell ENGL 1102 8 February 2013 Symbolism at Its Finest Many authors through time and through this day and age have used symbolism in their works. Critics may say there is too much symbolism in some works. There is never too much symbolism in a work. Symbolism enhances the characters‚ words‚ places‚ and objects to levels that a average work could not reach without the use of symbolism. The more symbolism an author uses‚ the more attached a reader becomes to the story. Look at August
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simplest dicarboxylic example is oxalic acid (COOH)2‚ which is just two connected carboxyls. Mellitic acid is an example of a hexacarboxylic acid. Other important natural examples are citric acid (in lemons) and tartaric acid (in tamarinds). Salts and esters of carboxylic acids are called carboxylates. When a carboxyl group is deprotonated‚ its conjugate base forms a carboxylate anion. Carboxylate ions are resonance stabilized and this increased stability makes carboxylic acids more acidic than alcohols
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Temperature INTRODUCTION The main purpose of the experiment is to investigate the effects of column temperature and flow rate on the separation of methyl esters compounds. On top of that‚ the experiment is conducted to explore the gas chromatography‚ which is include the concepts of retention time and resolution using a mixture of methyl esters: methyl linolate‚ methyl laurate‚ methyl myristate‚ and methylpalmitate and methyl stearate. In this experiment‚ the isothermal and temperature programming
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A- HPTLC Flavonoid profile of methanol extract M. concanensis leaves B- HPTLC Flavonoid profile of methanol extract M. concanensis flowers C- HPTLC Flavonoid profile of methanol extract M. concanensis seeds 4.2.3.1 C) HPTLC Phenol profile of M. concanensis Nimmo. HPTLC finger printing of M. concanensis was done by using selected solvent system Chloroform: Ethyl acetate: Formic acid (50%:40%:10%v/v) for leaf‚ flower and seed extracts‚ visualized under UV 254 and 366 nm showed more
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Preparation and purification of acetylsalicylic acid Results and Data treatment (A) Preparation of aspirin i) Details about the reactants Reaction of the acetylation of salicylic acid is following From the balanced reaction above‚ it can be seen that the stoichiometry between salicylic acid and acetic anhydride is 1: 1. In this experiment‚ 21.7mmol of salicylic acid was used to react 6.0mL of acetic anhydride and salicylic acid was limiting reagent. The expected amount of salicylic
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on the Heinemann website. 2. Read Section 13.5 in your Chemical Ideas book which deals with naming and making esters. Chemical Ideas 1. While doing Chemical Ideas 13.5 there is no need to cover polyesters (page 318) or ester hydrolysis (page 319). These will be covered in Designer Polymers (DP). As a result there is no need to do Problems 4‚ 6 (parts d & e) or 8 (parts d & e). 2. Add Esters from salicylic acid (page 315). 3. Note that the anhydride reactions on pages 318–319 do not need to be learned
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