Sodium hydrogencarbonate production

A marked difference in the product pattern has been reported for the treatment of cellobiose with either NaOH or NaHCOs. The formation of 3-deoxy-2-0-(hydroxymethyl)pentonic acids (52) from cellobiose is less important in sodium hydrogencarbonate solution than in sodium hydroxide, while the relative amounts of 2-deoxytetronic, 3-deoxypentonic, and 3,4-dideoxypentonic acids are much larger. 

With solid sodium hydrogencarbonate instead of the azide, compound jy gave as the main product (85%), together with a trace of 42 (14) This recalls a related precedent, namely, jT-elimination of... 

Treatment of 107 with 75 in the presence of 0.15-0.45 mol. equivalent of p-toluenesulfonic acid for 40 - 50 h at room temperature gave60 the (5RS)-5-[(RS)-dimethoxyphosphinyl]-5-(p-tolylsulfonylhydrazino)hexo-furanoses 108 (70% yield). Likewise, compound 107 and methyl phenyl-phosphinate gave an 100% yield of the 5-[(methoxy)phenylphos-phinyl] compound 109, whereas hydrazone 106 afforded four products, namely, two isomers of the xylofuranoses 110 (15%) and two isomers of the 5-C-[(RS)-(0,P-anhydro)phenylphosphinyl] derivatives 111 (51 and 26%). Compound 111 was considered to be produced from 110 during isolation employing sodium hydrogencarbonate, because 110 readily afforded 111 by treatment with sodium methoxide. 

An alternative procedure for the protection of L-sorbose (25), followed by oxidation at C-l and cyclization of the product to L-ascorbic acid, was developed by Hinkley and Hoinowski.257 L-Sorbose (25) was converted into methyl a-L-sorbopyranoside (37) by treatment with methanol and hydrogen chloride.258 Glycoside 37 was then oxidized with air in the presence of a suspension of platinum oxide in aqueous sodium hydrogencarbonate solution at 60°, to afford methyl ot-L-xylo-2-hexulopyranosidonic acid (38), which, when heated in hydrochloric acid, was converted into L-ascorbic acid (1), presumably by way of L-xy/o-2-hexulosonic acid (see Scheme 5). Acid 38 has also been prepared by oxidation of 37 with nitrogen tetraoxide.259,280 Yields were not reported for this reaction sequence, and it appears to offer no potential... 

Sodium hydrogencarbonate, NaHCOs, is used in the manufacture of some toothpastes and as a raising agent in food production. The purity of this substance can be obtained by measuring how much carbon dioxide is given off. 

Oxidation of 3,4-dihydropyrimidin-2(l //)-oncs (DHPMs) with ceric ammonium nitrate (CAN) in acetic acid resulted in ethyl 2,4-dioxo-6-phenyltetrahydropyrimidin-5-carboxylates as the major product. However, DHPMs undergo a regioselective oxidation with CAN in the presence of sodium hydrogencarbonate in neutral aqueous acetone solution to yield ethyl 6-meihyl-4-aryl(alkyl)pyrimidin-2(l //)-one-5-carboxylates. A mechanism involving a nitrolic acid intermediate has been suggested.72... 

It has been demonstrated that optically active oxetanes can be formed from oxazolidinone 92, a crotonic acid moiety functionalized with Evans chiral auxiliary (Scheme 18) <1997JOC5048>. In this two-step aldol-cyclization sequence, the use of 92 in a deconjugative aldol reaction, with boron enolates and ethanal, led to formation of the syn-aldol 93. This product was then converted to the corresponding oxetanes, 94a and 94b, via a cyclization with iodine and sodium hydrogencarbonate. This reaction sequence was explored with other aldehydes to yield optically active oxetanes in similar yields. Unlike previous experiments using the methyl ester of crotonic acid, in an analogous reaction sequence rather than the oxazolidinone, there was no competing THF formation. 

Tilak et described the use of excess mixed carbonic anhydrides to force condensation reactions to completion followed by the destruction of the excess mixed anhydride via the addition of aqueous potassium hydrogencarbonate. Hydrolysis of the nnixed anhydride was rapid and the resulting protected dipeptide could be extracted into ethyl acetate in a high state of purity, leaving the excess amino acid derivative and the salts in the aqueous phase. Without further purification the protected dipeptide was N -deprotected and reacted with the next mixed anhydride, and the process repeated until the desired peptide was obtained. Beyerman et al. substantially expanded the scope of this procedure and named it the REMA method for peptide synthesis (Repetitive Excess Mixed Anhydride).P°1 These reaction conditions provide an excellent method to ensure complete reaction of the amine component as well as rapid reaction rates and minimal side products. However, care must be taken to ensure that the excess carboxylic acid component is soluble in sodium hydrogencarbonate solution, e.g. when Z-Asp(OBzl)-OH is the acid component, it is extracted into the ethyl acetate as the sodium salt along with the product. With the due precautions the yields of small peptides are so high that the method could be applied without purification of the intermediate products, that is, in a repetitive way. 

Intramolecular participation of a neighboring hydroxy group is observed in the rearrangement of erythromycin A oxime (24) with p-toluenesulfonyl chloride and sodium hydrogencarbonate in acetone-water (equation 12). Interestingly, with the same reagent in pyridine-ether only the normal rearrangement product (25) is formed. 

Cycloaddition [72] Methacrolein 106 (0.83 mL, 10 mmol) and cyclopenta-diene 107 (1.20 mL, 12 mmol) were added to the above-mentioned suspension of the catalyst at -78 °C. The mixture was stirred for 2 h at this temperature and then quenched with aqueous sodium hydrogencarbonate solution. Filtration, washing of the resin, and evaporation of the volatiles gave the product 108 (1.16 g, 85%). 

Sometimes, dry caramels are required. These can be prepared either by treating hot (120 °) viscous caramel with ammonium carinate, followed by adding sucrose and orthophosphoric acid, cooling to 100 °, and adding citric acid and sodium hydrogencarbonate. Others proposed addition of such cereal products as rye flour, and conditioning of the mass at 80- 85 ° at pH... 

The crude product was isolated by concentration of the reaction mixture and addition of diethyl ether (40 mL). The organic phase was successively washed with aqueous hydrochloric acid (5%, 20 mL), saturated aqueous sodium hydrogencarbonate (25 mL) and saturated aqueous sodium chloride (25 mL), dried with anhydrous sodium sulfate, filtered and concentrated in a rotary evaporator at reduced pressure. 

Under a nitrogen atmosphere, 2-(2 -octynyloxy)-l-phenylethanone (1) (136 mg, 0.5 mmol) was added to a mixture of Pd(OAc)2 (5.6 mg, 0.025 mmol), 2,2 -bipyridine (4.5 mg, 0.030 mmol), HO Ac (1 mL), and 1,4-dioxane (4 mL). The solution was stirred at 80 °C for 14 hours until the reaction was complete as monitored by TLC. On cooling, the reaction mixture was neutralised with saturated sodium hydrogencarbonate, and then extracted with diethyl ether (3 x 20 mL). The combined ether solution was washed with saturated sodium chloride, dried with sodium sulfate and concentrated. The residue was purified by flash chromatography on silica gel (EtOAc/petroleum ether 1/4) to give the product 3-phenyl-3-hydroxy-4-(l -acetoxyhexylidene)tetrahydrofuran (2) in 80% yield as a white solid m.p. 79.5-80.5 °C. 

A( -Disulfonamides are decomposed with sodium hydrogencarbonate in DMSO to give ketones. Imines formed from the reaction of primary amines with carbonyl compounds can be oxidized to ox-aziridines with MCPBA which hydrolyze to aldehydes or ketones with acid. When acetone is used, the final by-products are ammonia and acetone (equation 37). The use of 2-pyridinecarbaldehyde is preferred since it gives an acid-soluble by-product which aids work-up (equatirai 38)." ... 

The production cycle starts with the extraction of sodium chloride. About 20% of the world s salt consumption goes into soda ash production [24]. The next step after rock salt mining is the production and purification of brine yielding a concentrated aqueous sodium chloride solution [8,25-27]. A parallel step is the production of carbon dioxide gas by calcination of limestone. The brine is treated with ammonia and carbon dioxide under precipitation of the less-soluble sodium hydrogen-carbonate. Ammonia is recovered by mixing the mother liquor with calcium hydroxide and stripping off the ammonia with steam. Thermal decomposition of sodium hydrogencarbonate yields synthetic soda ash [8,20,22,23,28-38]. The output of soda ash produced by the ammonia-soda process amounts to about two-thirds of the world production [22,23]. 

The success of the Solvay process lay in the efficient use of the ammonia obtained as a by-product in the coke industry. The key step involves the reaction of ammonia gas and carbon dioxide gas in a saturated sodium chloride solution. That results in the formation of sodium hydrogencarbonate (bicarbonate) NaHCOj and ammonium chloride. The sodium bicarbonate precipitate is filtered from the solution, dried and heated to form sodium carbonate. Carbon dioxide is obtained by heating limestone CaCOj in a lime kiln. One noteworthy feature of the Solvay process is the effective use and recycling of materials. The only ultimate by-product is calcium chloride Ca-CI2, for which the demand is limited. To some extent it is used for deicing roads in winter and for dust control on dirt roads in the summer. 

The reduction of several organic compounds with hydroorganosilane/organic acid systems has been studied in some detail. [544] Trifluoroacetic acid is the best proton donor, but sometimes acetic acid is used. The reduction occurs at 20-60°C, usually without a solvent. After the reaction, the product may be neutralised with base, usually an aqueous solution of sodium hydrogencarbonate, separated and distilled. The formation of a carbonium ion is decisive for the reduction of alkenes and cyclo alkanes, and this is more difficult when the alkene chains are straight. Alkenes and cycloalkenes which do not have a C substituent on the double bond do not react. The final products do not include esters of trifluoroacetic acid [545] (Scheme 4.1) ... 

Potassium chloride is reacted with carbon dioxide in precarbonated isopropylamine solution under pressure in an autoclave. Potassium hydrogencarbonate precipitates and the amine is converted into isopropylamine chlorohydrate. The potassium salt is isolated by filtration, washed free of amine and heated to convert it to the carbonate. Unreacted amine present in the filtrate is recovered by distillation. Hydrated lime is then added to convert the isopropylamine chlorohydrate back to the amine, which is also recovered by distillation. The main uses of potassium carbonate are the production of glass and sodium silicate. 

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