Alkalizers

Fischer-Tropsch Process. The Hterature on the hydrogenation of carbon monoxide dates back to 1902 when the synthesis of methane from synthesis gas over a nickel catalyst was reported (17). In 1923, F. Fischer and H. Tropsch reported the formation of a mixture of organic compounds they called synthol by reaction of synthesis gas over alkalized iron turnings at 10—15 MPa (99—150 atm) and 400—450°C (18). This mixture contained mostly oxygenated compounds, but also contained a small amount of alkanes and alkenes. Further study of the reaction at 0.7 MPa (6.9 atm) revealed that low pressure favored olefinic and paraffinic hydrocarbons and minimized oxygenates, but at this pressure the reaction rate was very low. Because of their pioneering work on catalytic hydrocarbon synthesis, this class of reactions became known as the Fischer-Tropsch (FT) synthesis. 

The alkalized zinc oxide—chromia process developed by SEHT was tested on a commercial scale between 1982 and 1987 in a renovated high pressure methanol synthesis plant in Italy. This plant produced 15,000 t/yr of methanol containing approximately 30% higher alcohols. A demonstration plant for the lEP copper—cobalt oxide process was built in China with a capacity of 670 t/yr, but other higher alcohol synthesis processes have been tested only at bench or pilot-plant scale (23). 

Fluorides. Tantalum pentafluoride [7783-71-3] TaF, (mp = 96.8° C, bp = 229.5° C) is used in petrochemistry as an isomerization and alkalation catalyst. In addition, the fluoride can be utilized as a fluorination catalyst for the production of fluorinated hydrocarbons. The pentafluoride is produced by the direct fluorination of tantalum metal or by reacting anhydrous hydrogen fluoride with the corresponding pentoxide or oxychloride in the presence of a suitable dehydrating agent (71). The ability of TaF to act as a fluoride ion acceptor in anhydrous HF has been used in the preparation of salts of the AsH, H S, and PH ions (72). The oxyfluorides TaOF [20263-47-2] and Ta02F [13597-27-8] do not find any industrial appHcation. 

Commercial cocoa powders are produced for various specific uses and many cocoas are alkaH treated, or Dutched, to produce distinctive colors and flavors. The alkaH process can involve the treatment of nibs, chocolate Hquor, or cocoa with a wide variety of alkalizing agents (9). 

The system aluminum/water belongs to group II where represents the pitting potential and lies between -0.8 and -1.0 V according to the material and the medium [22,23,36,39,42]. Since alkali ions are necessary as opposite ions to the OH ions in alkalization, the resistance increases with a decrease in alkali ion concentration (see Fig. 2-11). In principle, however, active aluminum cannot be protected cathodically [see the explanation of Eq. (2-56)]. 

Alkalizing and film-forming inhibitors are used to prevent corrosion in water containing Oj or salt. These include NajCOj, NaOH, Na3P04, Na2Si03, NaNOj and Na2Cr04. The number of organic compounds that effectively inhibit metal... 

Fiber Organic Solvents Animal, Vegetable, and Peiro Oils Microorg anisms Alkal Orga-ies nic Acids Oxidi- zing Agents Miner- al Acids Temperature Limits ( F)... 

The respective amide was prepared from 7-substituted 5-oxo-2,3-dihydro-5//-pyrido[l,2,3-de]-l,4-benzoxazine-6-carboxylic acids via acid chlorides with different benzylamines (00M1P3). 6-Carboxamides were N-benzylated, and a side-chain phenolic hydroxy group was O-alkylated. 7-Aryl-5-oxo-2,3-dihydro-5//-pyrido[l, 2,3-r/e]-1,4-benzoxazine-6-carboxylic acid was obtained from the ethyl ester by alkalic hydrolysis. 

Ox 0-2,3-dihydro-7//-pyrido[l, 2, i-de]-1,4-benzoxazine-6-carboxylic acids were prepared from 6-esters under acidic (96JAP(K)96/291144, 98MIP19, 98MI37, 99H(51)1563, 99MI36, 00MI76) and under alkalic conditions (OOMIPIO). 

Hydrolysis of ethyl 9-fluoro-10-(4-methylpiperazino)-7-oxo-2,3-dihydro-7//-pyrido[l,2,3- fe]-l,4-benzothiazine-6-carboxylate in a boiling mixture of AcOH and 35% HCl afforded 7 HCl (97USP5703233). That of (3S)-3-methyl-10-(2,6-dimethyl-4-pyridyl)-7-oxo-2,3-dihydro-7//-pyrido[l,2,3- e]-l,4-benzothiazine-6-carboxylate gave the 6-carboxylic acid (OOMIPIO). 7-Oxo-2,3-dihydro-7//-pyrido[l,2,3- fe]-l,4-benzothiazine-6-carboxylic acid was obtained from its ethyl ester by alkalic hydrolysis in 20% yield (99AP19). 

A side chain carboxyl group in perhydropyrido[l,2-a]pyrazines was obtained from an ester group by acidic or alkalic hydrolysis. A side chain carboxyl group was converted into a carboxamide group by the treatment with an amine in the presence of 1-hydroxybenzotriazole (OOJAP(K)OO/ 86659). 

Aik., abbrev. (Alkohol) alcohol, alkal., abbrev. (alkalisch) alkaline. 

A solution of 27.2 parts of 4-diisopropvlamino-2-phenvl-2-(2-pvridvl)butyronitrile in 200 parts of concentrated sulfuric acid is heated on a steam bath for 4 hours and then poured onto ice. The resultant mixture is alkalized with ION sodium hydroxide, and the pH is adjusted to 6 by the addition of acetic acid. The solution is washed once with benzene before it is alkalized again with ION sodium hydroxide solution. The resultant mixture is extracted with benzene, and the solvent is evaporated from the benzene extract. The resultant residue is dissolved in ethanol and the alcohol solution is treated with charcoal and filtered. Evaporation of the solvent leaves a residue which is recrystallized from hexane to give 4-diisopropvlamino-2-phenvl-2-(2-Pvridvl)butyramide melting at about 94.5°-95°C. 

Cooling is effected in the ice-bath while slowly adding concentrated HCI up to a pH of 2, while maintaining the temperature around 5°C. It is filtered and an equal volume of HjO is added. If the solution is cloudy it is washed in ether. It is alkalized by aqueous NaOH (40%), and the oil formed is extracted with ether. The ether phase is washed with water saturated with NaCI, then it is dried over anhydrous NajS04. 

One mol of 2,6-xylidine is dissolved in 800 ml glacial acetic acid. The mixture is cooled to 10°C, after which 1.1 mol chloracetyl chloride is added at one time. The mixture is stirred vigorously during a few moments after which 1,000 ml half-saturated sodium acetate solution, or other buffering or alkalizing substance, is added at one time. The reaction mixture is shaken during half an hour. The precipitate formed which consists of cj-chloro-2,6-di-methyl-acetanilide is filtered off, washed with water and dried. The product is sufficiently pure for further treatment. The yield amounts to 70 to 80% of the theoretical amount. 

A mixture of 14.1 parts of 1 -benzyl-4-cyano-4-piperidinopiperidine and 40 parts of 90% sulfuric acid is heated on a steam bath for 10 minutes. Without further heating, the mixture is stirred until a temperature of about 20°C is obtained. The mixture is then poured into 150 parts of ice-water and the resultant solution is alkalized with excess ammonium hydroxide solution. The aqueous solution is decanted from the precipitated oil. On treating this oil with 80 parts of acetone, crystallization sets in. After one hour the solid is filtered off and dried to yield 1 -benzyI-4-piperidinopiperidine-4-carboxamide melting at about 137.5°C to MO C. 

Ethyl-2-methyl-3-(10,11) -dihydro-5H-dibenzo [a,d] cycloheptene-5-ylidene)-1 -pyrrolinium iodide (4.7 g) was dissolved in 7 cc of methanol. To this solution there were added 1.4 g of sodium boron hydride within about 80 minutes with stirring and stirring of the solution was continued for two hours to complete the reaction. The reaction mixture was acidified with 10% aqueous hydrochloric acid solution and then the methanol was distilled off. The residual solution was alkalized with 20% aqueous sodium hydroxide solution and extracted with ether. The ether layer was dried over magnesium sulfate and the ether was distilled off. The resulting residue was further distilled under reduced pressure to yield 2.0 g of 1-ethyl-2-methyl-3-(10,11 ) dihydro-5H-dibenzo[a,d]cycloheptene-5-ylidene)pyrrolidine (boiling point 167°C/4 mm Hg.). 

The formyl derivative is then hydrolyzed by refluxing with 50% sulfuric acid for about 4 hours, after which the hydrolysate is extracted with ether to remove the acid-insoluble material and the aqueous solution made strongly alkaline with any suitable alkalizing agent, for example, sodium hydroxide, to liberate the amine. 

N sulfuric acid (100, 80,80 ml). The acid solution Is then alkalized and extracted with ether (2 x 150 ml and 1 x 100 ml), dried over MgS04 and the solution evaporated to dryness yielding substantially pure 5-(3-methylaminopropyl)-5H-dibenzo[a,d] cycloheptene according to U.S. Patent 3,244,748. 

An older method of cellulose fiber modification is mercerization [22,33-36], which has been widely used on cotton textiles. Mercerization is an alkali treatment of cellulose fibers. It depends on the type and concentration of the alkalic solution, its temperature, time of treatment, tension of the material, and the additives used [33,36]. At present there is a tendency to use mercerization for natural fibers as well. Optimal conditions of mercerization ensure the improvement of the tensile properties [33-35,37] and absorption characteristics [33-35], which are important in the composing process. 

Where the feed contains a large proportion of treated water, softening is a minimum requirement and the raw water quality dictates whether a more sophisticated form of external treatment would be preferable. If the water has a high alkalinity it calls for de-alkalization and base exchange. De-ionization is the ideal water treatment, but is usually avoided if possible because of its cost and use of corrosive chemicals. Membrane processes giving partial de-ionization are not normally installed at present, but are certain to become important in the future. 

The effect is best illustrated by a numerical example (Table 31.4). Let us take the case of hard and alkaline deep well water such as that found to the north of London, whose main characteristics are shown in the first column of Table 31.4. The second column shows its quality after de-alkalization has removed nine-tenths of the temporary hardness and converted it into CO2 gas. This is removed from the water by stripping it with air in a packed degassing column, and the product then softened in the third stage to yield the product shown in the third column. 

De-alkalization resins are regenerated with sulfuric or hydrochloric acid. Sulfuric acid is cheaper and easier to... 

De-alkalization resins must not be over-regenerated or the product water becomes strongly acidic. The system therefore needs some measure of skilled supervision, and may depend on a pH meter - an instrument that, in turn, needs regular and skilled maintenance. 

The de-alkalized and degassed water has a pH of 4-5 and (having just passed through an air-blown tower) is laden with oxygen and extremely corrosive. Normal practice is to dose NaOH into the degasser tower sump, at a level sufficient to approach to desired boiler water pH. If this dosing fails, severe corrosion in the degassed water pump, the softener and the feed system will result. 

The water supply for boilers is usually treated. Treatment depends on the quality of the water supply, the pressure of the boiler, the heat flux through the tube walls and the steam quality required. Most waters require de-alkalization. The water produced in this process is nonscaling and potentially corrosive (see above). 

---