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09:02 Dec 23, 2016
English to English translations [PRO] Law/Patents - Chemistry; Chem Sci/Eng / chemical patents
English term or phrase:eq.
To a solution of N-(tert-Butoxycarbonyl)-L-valine (8.06 g, 37.1 mmol, 1.5 eq.) in anhydrous ACN (60 mL) was added carbonyldiimidazole (6.01 g, 37.1 mmol, 1.5 eq.).
To a solution of 293-5 (500 mg, 775.37 µmol) in pyridine (5 mL) was added hydroxylamine hydrochloride (215.5 mg, 3.10 mmol, 4.00 eq.) in one portion at 0 °C under N2.
What does eq. stand for? I appreciate your help. Thanks.
As Karen Tkaczyk has said, eq stands for 'molar equivalent'. This is very clear in the 2nd example where the quantity of hydroxylamine hydrochloride (3.10 mmol) is exactly four times the quantity of 293-5 (775.37 µmol), i.e. for each molecule of 293-5 (whatever that is) there are four molecules of hydroxylamine hydrochloride, hence 4.00 eq. The situation is a bit more complicated in the first example. For each molecule of N-(tert-Butoxycarbonyl)-L-valine in the mixture, there is exactly one molecule of carbonyldiimidazole because the total quantity of each compound is 37.1 mmol. So why 1.5 eq and not 1.0 eq? My guess is that the quantity of reactants is being compared with the quatiry of the reaction product, i.e. the reaction produces 37.1/1.5=24.73 mmol of the reaction product.
Many important substances in the body are measured in equivalents. The technical definition of an equivalent is the amount of substance it takes to combine with 1 mole of hydrogen ions. As an example, we can look at hydrochloric acid (HCl). It takes approximately 35 grams of chloride (1 mole), to combine with 1 gram of hydrogen (1 mole) to make 1 mole of HCl (which weighs approximately 36 grams). Since both of these elements are monovalent (carrying a valence charge with a magnitude of 1), they combine in a one-to-one ratio. Therefore the amount of chloride that is needed to combine with one mole of hydrogen is 1 mole or 1 equilvalent (eq).