When you are polymerizing a urethane prepolymer, and there is solvent used in the cook plus a significant amount of water in the solvent, do you treat the calc. of water as 18g/mol or 9g/eq. Water has two active hydrogens, so isn't its functionality 2?
Pat Hennessey
The reaction is R-NCO + HOH --> R -NHCOOH --> RNH2 + CO2. The only "2" in the equation is as a subscript, not a coefficient.
John Aspen Research, -
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In a typical polyurethane formulation, 1 mole of water reacts with 2 moles of isocyanate => its equivalent weight is indeed 9 g/eq. This is because R-NCO + HOH --> R -NHCOOH --> RNH2 + CO2 followed by RNH2 + RNCO -->R-NH-CO-NH-R (urea). unless stoechiometry is way out of balance, of course... "Patrick Hennessey" a écrit dans le message de news:e2qndh$ snipped-for-privacy@dispatch.concentric.net...
hydrogens, so
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