Ammonium sulfate mechanical addition

A 500-ml, three-necked, round-bottom flask is fitted with a mechanical stirrer, a thermometer, and a wide-stern (powder) funnel. The flask is cooled in an ice-salt bath and charged with 125 ml (approx. 0.5 mole) of 15% sodium hydroxide solution. When the stirred solution reaches -10°, 30% hydrogen peroxide (57.5 g, 52.5 ml, approx. 0.5 mole) previously cooled to -10° is added in one portion. The pot temperature rises and is allowed to return to —10° whereupon 37.5 g (0.25 mole) of phthalic anhydride (pulverized) is added rapidly with vigorous stirring. Immediately upon dissolution of the anhydride, 125 ml (approx. 0.25 mole) of cooled (-10°) 20% sulfuric acid is added in one portion. (The time interval between dissolution of the anhydride and the addition of the cold sulfuric acid should be minimized.) The solution is filtered through Pyrex wool and extracted with ether (one 250-ml portion followed by three 125-ml portions). The combined ethereal extracts are washed three times with 75-ml portions of 40% aqueous ammonium sulfate and dried over 25 g of anhydrous sodium sulfate for 24 hours under refrigeration. 

Pejakovic V, Kronherger M, Mahrova M, Vilas M, Tojo E, Kalin M (2012) Pynolidinium sulfate and ammonium sulfate ionic liquids as lubricant additives for steel/steel contact lubrication. Proceedings of the Institution of Mechanical Engineers, Part J. J Eng Tribol 226 (J11) 923-932. doi 10.1177/1350650112448978... 

Muscle phosphorylase exists in (a) and (b) forms. The latter is half the molecular weight of the former and requires AMP as an activator, but since the AMP concentration (5 x 10 m per liter) required for the activation is not reached in muscle, the (b) form is practically inactive. In passing from one form to another, two enzymes are involved—a proteolytic enzyme catalyzes the breakdown of phosphorylase (a), and another catalyzes the formation of (a) from (b) in the presence of ATP, magnesium, and manganese. The stoichiometry of the second reaction has been studied four molecules of ATP for each molecule of phosphorylase (b) appear to be involved. It has been shown that both phosphorylase (a) and (b) contain pyridoxal phosphate the (b) form contains two such molecules, and the (a) form contains four. The role of the coenzyme in the mechanism of action of phosphorylase is unknown, but the enzyme loses its activity when the coenzyme is dissociated from the main protein molecule by ammonium sulfate activity is restored by the addition of pyridoxal phosphate. 

Since dimethyl sulfate decomposes rapidly in concentrated alkaline medium, addition of the powdered tartaric acid amide must begin immediately after the dimethyl sulfate is introduced. The amide should be added as fast as possible (ca. 20-30 min) within the limits of the capacity of the reflux condenser and the mechanical stirrer. The amount of dimethyl sulfate can be increased up to 2.5 equivalents and fresh benzyltriethyl-ammonium chloride can be added toward the end of the addition. With less rapid addition and stirring, the yield drops to 45-55%. 

A. 2,3-Bls(phenylsulflnyl)-1,3-butadiene. In a 2-L, three-necked, round-bottomed flask equipped with a mechanical stirrer, 25-mL dropping funnel, and a nitrogen inlet, are placed 7.75 g (0.09 mol) of 2-butyne-1,4-diol (Note 1), 37.6 ml. (0.27 mol) of triethylamine, and 700 mL of dichloromethane. After the diol is completely dissolved, the mixture is cooled to -78°C. To this solution is added 26.0 g (0.18 mol) of phenylsulfenyl chloride (Note 2) over a 30-min interval. The mixture is gradually warmed to room temperature and stirred for an additional 12 hr. The solution is then washed with 100 mL each of water, saturated ammonium chloride solution, saturated sodium bicarbonate solution, and brine, and dried over sodium sulfate. After filtration and concentration, the residue is recrystallized from methanol-ether (1 1) to give 20.1 g (74%) of 2,3-bis(phenylsulfinyl)-1,3-butadiene as a 1.1 1 mixture of diastereomers (Note 3). 

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