Acetate Facilitated Nickel Catalyzed Coupling of Aryl Chlorides and Alkyl Thiols

We report a mild, fast and convenient catalytic system for the coupling of aryl chlorides with primary, secondary, as well as previously challenging tertiary alkyl thiols using an air-stable nickel(II) precatayst in combination with the low-cost base potassium acetate at room temperature. This new catalytic system tolerates a variety of functional groups and enables the generation of thioethers for a wide range of substrates, including pharmaceutical compounds in excellent yields. Chemoselec-tive functionalization of disubstituted substrates was demonstrated. Kinetic and NMR-studies, as well as DFT computations support a Ni(0)/Ni(II) catalytic cycle and identify the oxidative addition product as the resting state. Acetate coordination and subsequent acetate facilitated formation of a thiolate complex via internal deprotonation play a key role in the catalytic cycle.

Potassium-Containing Fluids for Diabetic Ketoacidosis

OBJECTIVE The purpose of this process improvement project was to determine the appropriate potassium concentration of stocked IV fluids used in the treatment of diabetic ketoacidosis (DKA) at the Children's Hospital of The King's Daughters (CHKD) Emergency Department. METHODS This is a retrospective chart review from July 1, 2018, through June 30, 2019. Patients ≤21 years of age with laboratory-confirmed DKA were included. The primary outcome was to determine the most used potassium concentration (20 mEq/L or 40 mEq/L) for stocked IV fluids. Secondary efficacy and safety outcomes included the percent of appropriately ordered fluids per the DKA treatment protocol, percent of patients who maintained goal serum potassium concentration, comparison of time from physician ordering to administration of prescribed IV fluids (t-elapsed), and comparison of serum potassium concentrations between the point of care (POC) test and basic metabolic panel (BMP). RESULTS Of the 113 patients included, 73 (64.6%) received 40 mEq/L, 7 of whom received half potassium acetate plus half potassium phosphate, and 40 (35.4%) received 20 mEq/L potassium IV fluids. In 101 patients (89.4%), fluids were ordered appropriately per protocol. Of these patients, 53 (52.5%) maintained goal serum potassium concentration. The t-elapsed from physician ordering to administration of the prescribed fluid concentrations was not statistically significant. The mean POC versus BMP potassium concentration was statistically significant (4.56 mmol/L versus 4.96 mmol/L, respectively; 95% CI: −0.49 to −0.30; p < 0.001). CONCLUSIONS The CHKD pharmacy should stock the most used 40 mEq/L potassium IV fluids for DKA treatment.

Optimizing a Test Method to Evaluate Resistance of Pervious Concrete to Cycles of Freezing and Thawing in the Presence of Different Deicing Salts

The lack of a standard test method for evaluating the resistance of pervious concrete to cycles of freezing and thawing in the presence of deicing salts is the motive behind this study. Different sample size and geometry, cycle duration, and level of submersion in brine solutions were investigated to achieve an optimized test method. The optimized test method was able to produce different levels of damage when different types of deicing salts were used. The optimized duration of one cycle was found to be 24 h with twelve hours of freezing at −18 °C and twelve hours of thawing at +21 °C, with the bottom 10 mm of the sample submerged in the brine solution. Cylinder samples with a diameter of 100 mm and height of 150 mm were used and found to produce similar results to 150 mm-cubes. Based on the obtained results a mass loss of 3%–5% is proposed as a failure criterion of cylindrical samples. For the materials and within the cycles of freezing/thawing investigated here, the deicers that caused the most damage were NaCl, CaCl2 and urea, followed by MgCl2, potassium acetate, sodium acetate and calcium-magnesium acetate. More testing is needed to validate the effects of different deicers under long term exposures and different temperature ranges.

The effect of different deicing solutions on the moisture susceptibility of asphalt mixture

The present research studies the effectiveness and efficiency of solutions such as sodium chloride, magnesium chloride and potassium acetate on asphalt pavement to reduce the damage caused by moisture on asphalt pavement in winter. To prevent the stripping problem in asphalt, Nano-Zycotherm with three quantities corresponding to 0.1%, 0.2% and 0.3% weight of bitumen is used in this study. Under the saturated condition with the above solutions, the indirect tensile test performs by applying a freeze–thaw cycle as a means to measure the amount of moisture susceptibility. The results indicate that the asphalt mix containing 0.3% Nano-Zycotherm has a higher indirect tensile strength and tensile strength ratio than asphalt mix containing 0.1% and 0.2% Nano-Zycotherm. Accordingly, Magnesium chloride solution is the most effective deicing material to improve the indirect tensile strength and durability of asphalt pavements when faced with moisture and ice. Article highlights The presence of Nano-Zycotherm in asphalt leads to its increased resistance against stripping. The use of Sodium chloride and potassium acetate deicing solutions causes some damages in asphalt. Considering different solutions, magnesium chloride has the best performance against asphalt stripping.

OPTIMIZATION OF VINYL ACETATE PRODUCTION PROCESS

In the article, the kinetic laws and kinetics and mechanism of the oxidation acetylationreaction of ethylene in the vapour phase were studied in detail in a catalyst containing0,4%Рd+4%Cu+7%CH3COOK/HSZ. It was found that the total rate of the reaction was proportionalto the amount of unmodified and modified active sites of palladium (not clusters). Excess amountsof the modifier (both potassium acetate and copper) have been shown to block active sites byreducing catalyst efficiency.