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The main polycarbonate material is produced by the reaction of bisphenol A (BPA) and phosgene COCl 2. The overall reaction can be written as follows: The first step of the synthesis involves treatment of bisphenol A with sodium hydroxide, which deprotonates the hydroxyl groups of the bisphenol A. [6] (HOC 6 H 4) 2 CMe 2 + 2 NaOH → Na 2 (OC 6 ...
The reaction results in a polymer which is also soluble in the chosen solvent. Heat released by the reaction is absorbed by the solvent, reducing the reaction rate. Moreover, the viscosity of the reaction mixture is reduced, preventing autoacceleration at high monomer concentrations. A decrease in viscosity of the reaction mixture by dilution ...
The type I reaction dominates, which cause chain scission at the carbonyl unit to give a range of products. [1] [38] Type II Norrish reactions are less common but give rise to acetaldehyde by way of vinyl alcohol esters. [36] This has an exceedingly low odour and taste threshold and can cause an off-taste in bottled water. [39]
When exiting a reactor after a polymerization reaction, many polymers still contain undesired low-molecular weight components. These component may make the product unusable for further processing (for example, a polymer solution cannot directly be used for plastics processing), may be toxic, may cause bad sensory properties such as an unpleasant smell or worsen the properties of the polymer.
Carbonate esters can be converted to other carbonates by transesterification. A more nucleophilic alcohol will displace a less nucleophilic alcohol. In other words, aliphatic alcohols will displace phenols from aryl carbonates. If the departing alcohol is more volatile, the equilibrium may be driven by distilling that off. [2] [3]
Example Bjerrum plot: Change in carbonate system of seawater from ocean acidification.. A Bjerrum plot (named after Niels Bjerrum), sometimes also known as a Sillén diagram (after Lars Gunnar Sillén), or a Hägg diagram (after Gunnar Hägg) [1] is a graph of the concentrations of the different species of a polyprotic acid in a solution, as a function of pH, [2] when the solution is at ...
A polycarbonate is an oxocarbon dianion consisting of a chain of carbonate units, where successive carbonyl groups are directly linked to each other by shared additional oxygen atoms. That is, they are the conjugate bases of polycarbonic acids , the conceptual anhydrides of carbonic acid , or polymers of carbon dioxide .
One important class of condensation polymers are polyamides. [4] They arise from the reaction of carboxylic acid and an amine. Examples include nylons and proteins.When prepared from amino-carboxylic acids, e.g. amino acids, the stoichiometry of the polymerization includes co-formation of water: