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Sodium borohydride, also known as sodium tetrahydridoborate and sodium tetrahydroborate, [5] is an inorganic compound with the formula Na B H 4 (sometimes written as Na[BH 4]). It is a white crystalline solid, usually encountered as an aqueous basic solution .
For example, concentration gradients in ethanol solutions in water move 1 μm diameter colloidal particles with diffusiophoretic velocities of order 0.1 to 1 μm/s, the movement is towards regions of the solution with lower ethanol concentration (and so higher water concentration). [6]
At low pH values, it efficiently reduces aldehydes and ketones. [7] As the pH increases, the reduction rate slows and instead, the imine intermediate becomes preferential for reduction. [ 7 ] For this reason, NaBH 3 CN is an ideal reducing agent for one-pot direct reductive amination reactions that don't isolate the intermediate imine.
Mass transfer – Net movement of mass from one location, phase, etc. to another; Mass flux – Vector quantity describing mass flow rate through a given area; Osmosis – Migration of molecules to a region of lower solute concentration; Permeation – Penetration of a liquid, gas, or vapor through a solid
The viscosity of an aqueous solution can either increase or decrease with concentration depending on the solute and the range of concentration. For instance, the table below shows that viscosity increases monotonically with concentration for sodium chloride and calcium chloride , but decreases for potassium iodide and cesium chloride (the ...
In chemistry, the mass concentration ρ i (or γ i) is defined as the mass of a constituent m i divided by the volume of the mixture V. [1]= For a pure chemical the mass concentration equals its density (mass divided by volume); thus the mass concentration of a component in a mixture can be called the density of a component in a mixture.
Lithium borohydride (LiBH 4) is a borohydride and known in organic synthesis as a reducing agent for esters.Although less common than the related sodium borohydride, the lithium salt offers some advantages, being a stronger reducing agent and highly soluble in ethers, whilst remaining safer to handle than lithium aluminium hydride.
Sodium borohydride can, under some circumstances, be used for ester reduction, especially with additives. [ 1 ] Forming aldehydes from carboxylic acid derivatives is challenging because weaker reducing agents (NaBH 4 ) are often very slow at reducing esters and carboxylic acids, whereas stronger reducing agents (LiAlH 4 ) immediately reduce the ...