Potassium hydroxide production

Starting Molecule Ergonovinine Reagent Potassium hydroxide Products Ergonovinine ergonovine Ref. (Pioch 1956)... 

The cost of this preparation (particularly for large classes) can be appreciably reduced by using a solution of 20 g. of sodium hydroxide in 25 ml. of water, in place of the potassium hydroxide solution. In this case, however, the product on standing overnight forms a very hard mass, which should be dissolved in tcarm water. The yields of alcohol and acid are unchanged. 

Undecylenic acid (or 10-undecenoic acid) (I), a comparatively inexpensive commercial product obtained from castor oil, reacts with bromine in dry carbon tetrachloride to give 10 11-dibromoundecoic acid (II), which upon heating with a concentrated solution of potassium hydroxide yields 10-niidecynoic acid (III) ... 

The independent preparation of potassium phthabmide (from a solution of phthalimide in absolute ethanol and potassium hydroxide in 75 per cent, ethanol) may be avoided in many cases by boiling phthalimide with the halide in the presence of anhydrous potassium carbonate. The N-substituted phthalimide (I) is frequently cleav with difficulty this is often facilitated by reaction with hydrazine hydrate to give an intermediate product, which is easily decomposed by hydrochloric acid to 3deld the insoluble hydrazide of phthaUc acid (II) and the primary amine (III) ... 

Alternatively, treat a solution of 3 9 g. of the 6is-diazo ketone in 50 ml. of warm dioxan with 15 ml. of 20 per cent, aqueous ammonia and 3 ml. of 10 per cent, aqueous silver nitrate under reflux in a 250 or 500 ml. flask on a water bath. Nitrogen is gently evolved for a few minutes, followed by a violent reaction and the production of a dark brown and opaque mixture. Continue the heating for 30 minutes on the water bath and filter hot the diamide of decane-1 lO dicarboxyhc acid is deposited on cooling. Filter this off and dry the yield is 3 -1 g., m.p. 182-184°, raised to 184-185° after recrystallisation from 25 per cent, aqueous acetic add. Hydrolyse the diamide (1 mol) by refluxing for 2-5 hours with 3N potassium hydroxide (4 mols) acidify and recrystaUise the acid from 20 per cent, acetic acid. The yield of decane-1 10-dicarboxyhc acid, m.p. 127-128°, is almost quantitative. 

Synthesis of (A) started with the combination of 2,4,6-trimethylphenol and allyl bromide to give the or/Ao-allyl dienone. Acid-catalyzed rearrangement and oxidative bydroboration yielded the dienone with a propanol group in porlactone ring were irons in the product as expected (see p. 275). Treatment with aqueous potassium hydroxide gave the epoxy acid, which formed a crystalline salt with (R)-l-(or-naphthyl)ethylamine. This was recrystallized to constant rotation. 

Ethynylation of ketones is not cataly2ed by copper acetyUde, but potassium hydroxide has been found to be effective (180). In general, alcohols are obtained at lower temperatures and glycols at higher temperatures. Most processes use stoichiometric amounts of alkaU, but tme catalytic processes for manufacture of the alcohols have been described the glycols appear to be products of stoichiometric ethynylation only. 

Ma.nufa.cture. In general, manufacture is carried out in batch reactors at close to atmospheric pressure. A moderate excess of finely divided potassium hydroxide is suspended in a solvent such as 1,2-dimethoxyethane. The carbonyl compound is added, followed by acetylene. The reaction is rapid and exothermic. At temperatures below 5°C the product is almost exclusively the alcohol. At 25—30°C the glycol predominates. Such synthesis also... 

Continuous processes have been developed for the alcohols, operating under pressure with Hquid ammonia as solvent. Potassium hydroxide (206) or anion exchange resins (207) are suitable catalysts. However, the relatively small manufacturing volumes militate against continuous production. For a while a continuous catalytic plant operated in Raveima, Italy, designed to produce about 40,000 t/yr of methylbutynol for conversion to isoprene (208,209). 

Chlorine from Potassium Hydroxide Manufacture. One of the coproducts during the electrolytic production of potassium hydroxide employing mercury and membrane ceHs is chlorine. The combined name plate capacity for caustic potash during 1988 totaled 325,000 t/yr and growth of U.S. demand was expected to be steady at 2% through 1990 (68). 

Manufacture. Potassium biduoride is produced from potassium hydroxide or potassium carbonate and hydroduoric acid. The concentrated solution is cooled and allowed to crystallize. The crystals are separated centtifugaHy and dried. The commercial product consists typically of 99.7% KHF2 and 0.2% KF. Potassium biduoride is available in the United States in 180-kg dmms at 4.04/kg (1992). 

Alkali AletalIodides. Potassium iodide [7681-11-0] KI, mol wt 166.02, mp 686°C, 76.45% I, forms colorless cubic crystals, which are soluble in water, ethanol, methanol, and acetone. KI is used in animal feeds, catalysts, photographic chemicals, for sanitation, and for radiation treatment of radiation poisoning resulting from nuclear accidents. Potassium iodide is prepared by reaction of potassium hydroxide and iodine, from HI and KHCO, or by electrolytic processes (107,108). The product is purified by crystallization from water (see also Feeds and feed additives Photography). 

A Hquid-phase isophorone process is depicted ia Figure 4 (83). A mixture of acetone, water, and potassium hydroxide (0.1%) are fed to a pressure column which operates at head conditions of 205°C and 3.5 MPa (- 500 psi). Acetone condensation reactions occur on the upper trays, high boiling products move down the column, and unreacted acetone is distilled overhead ia a water—acetone a2eotrope which is recycled to the column as reflux. In the lower section of the column, water and alkaH promote hydrolysis of reaction by-products to produce both isophorone and recyclable acetone. Acetone conversion is typically ia the range 6—10% and about 70% yield of isophorone is obtained. Condensation—hydrolysis technology (195—198), and other Hquid-phase production processes have been reported (199—205). 

In the electrolysis of K2Mn04, one mole of KOH is coproduced for every mole of KMnO generated. This by-product potassium hydroxide must be recovered and utilized. For recycling, it also needs to be purified (130). Alternatively, the KOH can be converted into potassium carbonate by treatment with CO2 in the red-lye process (131). 

Sodium hydroxide, potassium hydroxide, or other caustic compounds are blended to make these types of removers. Polymer-type thickeners are added to increase the viscosity that allows the remover to be appHed with a bmsh, trowel, or spray. Some of these products use a paper or fabric covering to allow the remover finish mixture to be peeled away. The most common appHcation for this group of removers is the removal of architectural finishes from the interior and exterior of buildings. The long dwell time allows for many layers of finish to be removed with one thick appHcation of remover. 

Mitsubishi Chemical Industries, Ltd. practiced a Henkel II technology starting with toluene to produce benzoic acid. Reaction of benzoic acid with potassium hydroxide resulted in potassium benzoate, which was subjected to a disproportionation reaction to produce dipotassium terephthalate and benzene. Dipotassium terephthalate reacted with sulfuric acid, and the resulting terephthahc acid was recovered by filtration and drying (65,66). Here, dipotassium sulfate was the by-product. 

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