Aqueous alkaline

Fieser s solution An aqueous alkaline solution of sodium anthraquinone -sulphonale (silver salt) reduced with sodium dithionite, Na2S204, and used as a scrubbing solution for partially removing O2 from, e.g., N2. 

To obtain the benzoic acid, add an excess of concentrated hydrochloric acid carefully with stirring to the aqueous alkaline solution remaining from the original extraction. When no further precipitation of benzoic acid occurs, cool the solution (if perceptibly warm) in ice-water, and then filter at the pump. Wash the benzoic acid thoroughly with cold water, drain, and then recrystallise from a large volume of boiling water. Benzoic acid is obtained as colourless crystals, m.p, 121° yield, 19-20 g. 

The reaction is applicable to the preparation of amines from amides of aliphatic aromatic, aryl-aliphatic and heterocyclic acids. A further example is given in Section IV,170 in connexion with the preparation of anthranilic acid from phthal-imide. It may be mentioned that for aliphatic monoamides containing more than eight carbon atoms aqueous alkaline hypohalite gives poor yields of the amines. Good results are obtained by treatment of the amide (C > 8) in methanol with sodium methoxide and bromine, followed by hydrolysis of the resulting N-alkyl methyl carbamate ... 

Aqueous alkaline solution. This will contain any acids or phenols present. Cool, acidify (litmus) with dilute HjSO, and add excess of solid NaHCO,. Extract with ether. 

Aqueous alkaline solution (Sj). Neutralise with dilute HjSOi (Congo red). Evaporate to dryness and extract with absolute ethyl alcohol. The alcoholic extract contains the water-soluble, non-volatile components. 

Because of their use in the rubber industry various sulfenamido thiazoles (131) have been prepared. They are obtained in good yields through the oxidation of A-4-thiazoline-2-thiones (130) in aqueous alkaline solution in the presence of an amine or ammonia (Scheme 66) <123, 166, 255, 286, 308, 309). Other oxidizing agents have been proposed (54, 148. 310-313) such as iodine (152), chlorine, or hydrogen peroxide. Disulfides can also be used as starting materials (3141. 

Positive-Tone Photoresists based on Dissolution Inhibition by Diazonaphthoquinones. The intrinsic limitations of bis-azide—cycHzed mbber resist systems led the semiconductor industry to shift to a class of imaging materials based on diazonaphthoquinone (DNQ) photosensitizers. Both the chemistry and the imaging mechanism of these resists (Fig. 10) differ in fundamental ways from those described thus far (23). The DNQ acts as a dissolution inhibitor for the matrix resin, a low molecular weight condensation product of formaldehyde and cresol isomers known as novolac (24). The phenoHc stmcture renders the novolac polymer weakly acidic, and readily soluble in aqueous alkaline solutions. In admixture with an appropriate DNQ the polymer s dissolution rate is sharply decreased. Photolysis causes the DNQ to undergo a multistep reaction sequence, ultimately forming a base-soluble carboxyHc acid which does not inhibit film dissolution. Immersion of a pattemwise-exposed film of the resist in an aqueous solution of hydroxide ion leads to rapid dissolution of the exposed areas and only very slow dissolution of unexposed regions. In contrast with crosslinking resists, the film solubiHty is controUed by chemical and polarity differences rather than molecular size. 

An aqueous PVA solution containing a small amount of boric acid may be extmded into an aqueous alkaline salt solution to form a gel-like fiber (15,16). In this process, sodium hydroxide penetrates rapidly into the aqueous PVA solution extmded through orifices to make it alkaline, whereby boric acid cross-links PVA molecules with each other. The resulting fiber is provided with sufficient strength to withstand transportation to the next process step and its cross section does not show a distinct skin/core stmcture. 

Three types of electrochemical water-spHtting processes have been employed (/) an aqueous alkaline system (2) a soHd polymer electrolyte (SPE) and (J) high (700—1000°C) temperature steam electrolysis. The first two systems are used commercially the last is under development. 

A number of chemiluminescent reactions may proceed through unstable dioxetane intermediates (12,43). For example, the classical chemiluminescent reactions of lophine [484-47-9] (18), lucigenin [2315-97-7] (20), and transannular peroxide decomposition. Classical chemiluminescence from lophine (18), where R = CgH, is derived from its reaction with oxygen in aqueous alkaline dimethyl sulfoxide or by reaction with hydrogen peroxide and a cooxidant such as sodium hypochlorite or potassium ferricyanide (44). The hydroperoxide (19) has been isolated and independentiy emits light in basic ethanol (45). 

The presence of manganese can be detected by formation of the purple MnO upon oxidation using bismuth or periodate in acidic solution. A very sensitive test is the reaction of and formaldoxime hydrochloride in aqueous alkaline solution, which also leads to the production of a purple MnO ... 

This aqueous alkaline remover is used for stripping the finish from wood or ferrous metals at a mix ratio of 30—600 g/L (0.25—5 lbs/gal). 

If the dye contains no mobile substituents ia the chain, nucleophiles attack primarily the end carbon atoms (changing of terminal residues). Streptocyanines can be hydroly2ed ia aqueous alkaline solution to form the corresponding merocyanines and then the oxonoles (71,72). These processes are reversible. Nucleophilic reactions with the methylene bases of the corresponding heterocycles result ia polymethines containing new end groups (Fig. 

A.lkanolamine Process. Carbon dioxide is an acidic gas that reacts reversibly with aqueous alkaline solution to form a carbonate adduct. This adduct decomposes upon the addition of low level heat faciUtating CO2 removal. An aqueous solution of 15—20 wt % monoethanolamine (MEA) was the standard method for removing CO2 in early ammonia plants. 

Activated tertiary amines such as triethanolamine (TEA) and methyl diethanolamine (MDEA) have gained wide acceptance for CO2 removal. These materials require very low regeneration energy because of weak CO2 amine adduct formation, and do not form carbamates or other corrosive compounds (53). Hybrid CO2 removal systems, such as MDEA —sulfolane—water and DIPA—sulfolane—water, where DIPA is diisopropylamine, are aqueous alkaline solutions in a nonaqueous solvent, and are normally used in tandem with other systems for residual clean-up. Extensive data on the solubiUty of acid gases in amine solutions are available (55,56). 

The process by which a solubility differential between exposed and unexposed areas occurs is well known (74). Photodegradation products of the naphthoquinone diazide sensitizer, eg, a l,2-naphthoquinonediazide-5-sulfonic acid ester (11), where Ar is an aryl group, to an indene carboxylic acid confers much increased solubility in aqueous alkaline developer solutions. 

Low DS starch acetates ate manufactured by treatment of native starch with acetic acid or acetic anhydride, either alone or in pyridine or aqueous alkaline solution. Dimethyl sulfoxide may be used as a cosolvent with acetic anhydride to make low DS starch acetates ketene or vinyl acetate have also been employed. Commercially, acetic anhydride-aqueous alkaU is employed at pH 7—11 and room temperature to give a DS of 0.5. High DS starch acetates ate prepared by the methods previously detailed for low DS acetates, but with longer reaction time. 

Etherification. The reaction of alkyl haUdes with sugar polyols in the presence of aqueous alkaline reagents generally results in partial etherification. Thus, a tetraaHyl ether is formed on reaction of D-mannitol with aHyl bromide in the presence of 20% sodium hydroxide at 75°C (124). Treatment of this partial ether with metallic sodium to form an alcoholate, followed by reaction with additional aHyl bromide, leads to hexaaHyl D-mannitol (125). Complete methylation of D-mannitol occurs, however, by the action of dimethyl sulfate and sodium hydroxide (126). A mixture of tetra- and pentabutyloxymethyl ethers of D-mannitol results from the action of butyl chloromethyl ether (127). Completely substituted trimethylsilyl derivatives of polyols, distillable in vacuo, are prepared by interaction with trim ethyl chi oro s il an e in the presence of pyridine (128). Hexavinylmannitol is obtained from D-mannitol and acetylene at 25.31 MPa (250 atm) and 160°C (129). 

Propylthiouracil. This compound is a white, powdery, crystalline substance of starch-like appearance with a bitter taste. It is slightly soluble in water, chloroform, and ethyl ether, sparingly soluble in ethanol, and soluble in aqueous alkaline solutions (53). An extensive compilation of its chemical, spectral, and chromatographic properties is available (43). It is assayed titrimetrically with NaOH (53). 

Oxidation of Aromatic Amines. The technically important dye Direct Yellow 28 (23) [10114-47-3] (Cl 19555) for cotton usage is manufactured by oxidation of dehydrothio- i ra-toluidinesulfonic acid sodium salt with sodium hypochlorite ia aqueous alkaline solutioa. 

Developing agents must also be soluble in the aqueous alkaline processing solutions. Typically such solutions are maintained at about pH 10 by the presence of a carbonate buffer. Other buffers used include borate and, less frequendy, phosphate. Developer solubiUty can be enhanced by the presence of hydroxyl or sulfonamide groups, usually in the A/-alkyl substituent. The solubilization also serves to reduce developer allergenicity by reducing partitioning into the lipophilic phase of the skin (46). 

Many of the surfactants made from ethyleneamines contain the imidazoline stmcture or are prepared through an imidazoline intermediate. Various 2-alkyl-imidazolines and their salts prepared mainly from EDA or monoethoxylated EDA are reported to have good foaming properties (292—295). Ethyleneamine-based imida zolines are also important intermediates for surfactants used in shampoos by virtue of their mildness and good foaming characteristics. 2- Alkyl imidazolines made from DETA or monoethoxylated EDA and fatty acids or their methyl esters are the principal commercial intermediates (296—298). They are converted into shampoo surfactants commonly by reaction with one or two moles of sodium chloroacetate to yield amphoteric surfactants (299—301). The ease with which the imidazoline intermediates are hydrolyzed leads to arnidoamine-type stmctures when these derivatives are prepared under aqueous alkaline conditions. However, reaction of the imidazoline under anhydrous conditions with acryflc acid [79-10-7] to make salt-free, amphoteric products, leaves the imidazoline stmcture essentially intact. Certain polyamine derivatives also function as water-in-oil or od-in-water emulsifiers. These include the products of a reaction between DETA, TETA, or TEPA and fatty acids (302) or oxidized hydrocarbon wax (303). The amidoamine made from lauric acid [143-07-7] and DETA mono- and bis(2-ethylhexyl) phosphate is a very effective water-in-od emulsifier (304). 

Manufacture of alkylsulfones, important intermediates for metal-complex dyes and for reactive dyes, also depends on O-alkylation. An arylsulphinic acid in an aqueous alkaline medium is treated with an alkylating agent, eg, alkyl haUde or sulfate, by a procedure similar to that used for phenols. In the special case of P-hydroxyethylsulfones (precursors to vinylsulfone reactive dyes) the alkylating agent is ethylene oxide or ethylene chlorohydrin. 

In aqueous alkaline conditions with chloroacetic acid the pyrido[4,3- f]pyrimidinethione (80) undergoes facile ring opening, attributed to the resonance stabilization of a delocalized covalent hydrate dianion intermediate (81) (82). Pyrido[2,3- f]pyrimidine-4-thiones (and... 

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