Potassium-hydride

CONTACT WITH WATER LIBERATES HIGHLY FLAMMABLE 

Wear nitrile rubber gloves, fireproof clothing, goggles, and face shield. Work from behind body shield where possible. Cover spill with a 1 1 1 mixture by weight of sodium carbonate or calcium carbonate, clay cat litter (bentonite), and sand. Carefully transfer to a pail in the fume hood. Slowly and cautiously add butanol (about 10 mol solvent/mol hydride or about 22 mL per gram) to the hydride until the reaction ceases. Then add water very carefully until last of hydride is destroyed. Let stand until solids settle. Decant liquid into the drain. The solid residue may be disposed of with normal refuse.4 

Reactions for Spillage and Waste Disposal 2KH + 2CH CTlXHiCH2OH KOCHjCHjCHXHj + H2 

White or slightly yellow lumps, rods, or pellets mp, 360 C (anhydrous 380°C).  

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Potassium hydride (1 eq.) was washed with hexanes and suspended in anhydrous ether at 0°C. 7-Bromoindole was added as a solution in ether. After 15 min, the solution was cooled to — 78°C and t-butyllithium (2 eq.) which had been precooled to — 78°C was added by cannula. A white precipitate formed. After 10 min DMF (2 eq.) was added as a solution in ether. The reaction mixture was allowed to warm slowly to room temperature and when reaction was complete (TLC) the suspension was poured into cold 1 M H3PO4. The product was extracted with EtOAc and the extract washed with sat. NaHCOj and dried (MgS04). The product was obtained by evaporation of the solvent and purified by chromatography on silica gel (61% yield). 

Potassium hydride (KH) is a source of the strongly basic hydride ion ( H ) Using curved arrows to track electron movement write an equation for the reaction of hydride ion with water What is the conjugate acid of hydride lon ... 

Potassium hydride Air, chlorine, acetic acid, acrolein, acrylonitrile, maleic anhydride, nitroparaf-flns, A-nitrosomethylurea, tetrahydrofuran, water... 

Potassium, Pubidium, and Cesium idjdrides. Although all the other alkah metal hydrides have been synthesized and some of the properties measured, only potassium hydride [7693-26-7] is commercially available. KH is manufactured in small amounts and sold as a mineral oil dispersion. It is a stronger base than NaH and is used to make the strong reducing agent KBH(C2H )2 and the super bases RNHK and ROK (6). 

Potassium 3-aniinopropylaniide [56038-00-7] (KAPA), KNHCH2CH2CH2-NH2, pX = 35, can be prepared by the reaction of 1,3-diaminopropane and potassium metal or potassium hydride [7693-26-7] (57—59). KAPA powder has been known to explode during storage under nitrogen in a drybox, and is therefore made in situ. KAPA is extremely effective in converting an internal acetylene or aHene group to a terminal acetylene (60) (see Acetylene-DERIVED chemicals). 

Potassium Hydride. Potassium hydride [7693-26-7] KH, made from reaction of molten potassium metal with hydrogen at ca 200°C, is suppHed in an oil dispersion. Pressure Chemical Company (U.S.) is a principal suppHer. KH is much more effective than NaH or LiH for enolization reactions (63,64). Use of KH as a base and nucleophile has been reviewed (65). 

This derivative has been prepared from an indole, the chloromethyl ether, and potassium hydride in 50% yield it is cleaved in 84% yield by potassium cyanide/ 18-crown-6 in refluxing acetonitrile/ ... 

The submitters used a 35% dispersion of potassium hydride in mineral oil supplied by Alfa Products, Morton/Thiokol, Inc. the mineral oil was separated by washing the dispersion with five portions of dry hexane. The checkers used a 25% dispersion of potassium hydride in mineral oil obtained from the same source but without removing the mineral oil. The oil remained in the distillation pot when the product was distilled. 

Examine electrostatic potential maps for potassium hydride and hydrogen chloride. How are they similar and how are they different (Focus on whether the molecules are polar or nonpolar (compare dipole moments), and on the electronic character of hydrogen.) Draw the ionic Lewis structure that is most consistent with each electrostatic potential map. Does each atom have a filled valence shell ... 

Both NaH and KH are used to deprotonate alcohols. KH is more reactive than NaH. Compare atomic charges and electrostatic potential maps of potassium hydride and sodium hydride. For which is the hydrogen more negatively charged Which should be the better source of hydride ... 

Another factor to consider is the energy required to break solid MH into individual molecules. Calculate the dissociation energies for sodium hydride dimer and potassium hydride dimer, i.e. 

Electrostatic potential map for potassium hydride shows negatively-charged regions (in red) and positively-charged regions (in blue). 

The next step of the Peterson olefination allows for the control of the E Z-ratio of the alkene to be formed by proper choice of the reaction conditions. Treatment of /3-hydroxysilanes 5 with a base such as sodium hydride or potassium hydride leads to preferential -elimination to give alkene 3a as major... 

Kalium-hydrat, n. potassium hydroxide, -hy-drid, n. potassium hydride (KH). -hydroxyd, n. potassium hydroxide, -hydriir, n. potassium subhydride (IC2H or K4H2). -iridi-chlorid, n. potassium eh loroiridate. -jodat, n. potassium iodate. 

The synthesis of 1-benzothiepin (7) has also been achieved, in 80% yield, by the reaction of 4,5-dihydro-l-benzothiepin-5-ol (6) with potassium hydride and -toluenesulfonyl chloride and subsequent elimination of p-toluenesulfonic acid with lerf-pentylpotassium 22... 

The cyclopropane cyclizations by elimination of triflinic acid (CF3S02H) are readily effected by basic treatment of triflones (trifluoromethyl alkyl sulfones) with activated /-protons (equations 46 and 47)39. The cyclopropane diesters 45 are formed on treatment of 44 with potassium hydride in DMSO or sodium methoxide in methanol (equation 48). In contrast, the monoester 46 failed to give the desired cyclopropane40. Addition of carbanions derived from /f, y-unsaturated phenyl sulfones to a, /i-unsaturated carboxylic esters and subsequent elimination of benzenesulfinate ion give cyclopropanes possessing the unsaturated side chain and the ester function in trans positions (equation 49)41. 

Normant and coworkers50a have recently studied the intramolecular addition of nucleophiles to vinyl sulfones. The presence of the sulfonyl group in equations 58 and 59 is essential for the disfavored 5-endo-trigonal closure5013. In contrast, the corresponding sulfoxide gives no cyclic product when treated with potassium hydride and only decomposition occurs. 

Self-Test L.2A Calculate the mass of potassium metal needed to react with 0.450 g of hydrogen gas to produce solid potassium hydride, KH. 

ET-IR spectroscopy was employed to investigate the structures of the 1 1 complexes between Li" and the guanidine-substituted azo compounds pyiidine-2-azo-p-phenyltetramethylguanidine and 4,4 -bis(tetramethylguanidine)azoben-zene. Both Li" complexes exist as dimers in acetonitrile solution.The structural chemistry of potassium N,N -di(tolyl)formamidinate complexes has been investigated in detail. These compounds were prepared by deprotonation of the parent Af,N -di(tolyl)formamidines with potassium hydride (Scheme 13). The resulting adducts with either THE or DME display one-dimensional polymeric solid-state structures that exhibit /r-fj fj -coordinated formamidinates. 

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