Ammonium chloride thermodynamic

Investigation of thermodynamic behavior of monolayers formed from mixtures of bis[2-(n-hexadecanoyl)ethyl]methyl(4-vinylbenzyl) ammonium chloride (1) and dioctadecyl-dimethylammonium bromide (5) serves as the second example [116]. The determined surface-pressure/surface-area isotherms of mono-layers prepared from (1) and (5) and from their mixtures are given in Fig. 8. The isotherms showed the expected behavior following the liquid state there was a transition to the solid state in the region of 20-36 mNm 1. This transition was characterized by a pressure, and by a corresponding area, Aj. All isotherms intersected in the vicinity of 30 mNm-1 and, at surface-pressure/surface-area... 

Metal-ammonia reduction of ketones. Swiss chemists have reported a detailed study of the mechanism of this reaction, using for the most part (-l-)- 3,3-D2] camphor as substrate. The conclusions drawn have some useful practical applications. The choice of metal (Li, Na, or K) has little effect on the course of reduction to the thermodynamically more stable diastereoisomeric alcohol. The most important conclusion is that pinacol reduction can be suppressed completely in Na-NH3 reductions by use of ammonium chloride as the proton source, a finding first reported by Murphy and Sullivan.2 This salt also partially suppresses pinacol formation in Li-NHj reductions. It also suppresses reduction of enolates, and thus should decrease racemization in reduction of chiral ketones. 

To extend the study of the Sn(ANRORC) mechanism, 4-phenylpyrimidine (29) was chosen as a suitable substrate. First, it was shown by H- and C-NMR spectroscopy that addition of 29 to liquid ammonia containing excess potassium amide resulted in immediate formation of two anionic cr-adducts (79JOC4677). They were the kinetically favored 2-amino-l,2-dihydro-4-phenylpyrimidinide (30) and the thermodynamically stable 6-amino-I,6-dihydro-4-phenylpyrimidinide (31). After standing for 20 min, the ratio of 31 30 was 80 20. On further standing, 30 continued to diminish and finally disappeared. After 70 hr, the reaction mixture was quenched with ammonium chloride, which caused an immediate liberation of hydrogen, to give a 60% yield of 2-amino-4-phenylpyrimidine (32) and a 15% yield of 6-amino-4-phenylpyrimidine (33), with the remainder mostly starting material (Scheme 13). 

Further reaction of diaziridines is responsible for the formation of bicyclic compounds 122a-c from aldehydes, chloramine and ammonia. The isomers 122a and 122b (R = various alkyl, aryl, and aralkyl groups) are obtained in a kinetically controlled reaction work-up in the presence of ammonium chloride yields an additional isomer 122c as a result of thermodynamic control. 

This procedure uses readily available reagents and provides a simple and efficient method for nitrile synthesis. The entire sequence of four steps can be performed in a single day. Although product formation in the second step is presumably thermodynamically controlled, the cyanohydrazine is favored in all cases studied except with aryl ketones. A water-methanol solution of ammonium chloride and potassium cyanide can also be employed for the cyanohydrazine formation, but lower yields (ca. 60%) are obtained. The third step, a conveniently performed titration procedure with bromine as oxidant, can be effected with other oxidizing reagents such as 4-phenyl-4H-l,2,4-triazole-3,5-dione, ferl-butyl hypochlorite, and Jones reagent.12 The final diazene-... 

Precise values of the activity coefficients of aqueous ammonium chloride solutions at 25 °C, determined from e.m.f. measurements of cells with transference, have been reported for the concentration range 0—0.2moll. The results show no anomalous behaviour with respect to the Debye-Hiickel limiting law. An interpretation of excess thermodynamic functions of potassium and ammonium chloride solutions has been made in terms of ionic influences on solvent structure. ... 

In contrast to simple cyclic ketones, some strained, and also sterically hindered, ketones give the less stable isomer. Thus, reduction of various bicyclo[2.2.1]heptanones4 by alkali metals in liquid ammonia, alone or in combination with proton sources (alcohols or ammonium chloride), gives predominantly the mfo-alcohols, regardless of whether these are thermodynamically favored or not (see Table 2, p 3972). 

Steroidal 4,6-dien-3-ones, such as 4, and related compounds (see Table 7) are reduced initially to the 3,5-dienolates 5. As expected, protonation occurs axially giving the thermodynamically more stable product61,62. Protonation of 5 with ammonium chloride leads to the formation of the 5-en-3-one 663. Addition of proton donors, such as an alcohol or water, leads primarily to the same product (6), but under these conditions the /Ly-unsaturated ketone undergoes isomerization to the more stable a,/i-unsaturated product 76 65. 

However, there had not been a spectroscopic study that confirmed this HM. Moreover, this model is unable to explain certain experimental data and does not account for the thermodynamical requirement that the solution temperature be below the Krafft point for micellization to take place. In order to understand these discrepancies, adsorption of long-chain amines was studied spectroscopically on quartz and albite, and the results were compared with the indirect data [325, 372]. DRIFTS, IRRAS, and XPS of quartz and albite conditioned in solutions of dodecyl (C12) and hexadecyl (Cie) ammonium chloride (ACl) and acetate (AAc) of different initial concentrations (Cj,) were measured. 

Heyns and Koch succeeded [96] in confirming the structure of the rearrangement product from the reaction of D-fructose and ammonium chloride in the presence of phosphate and proposed a mechanism (Scheme 28). They pointed out that both epimers at position C-2, D-glucosamine (4) and D-mannosamine (5), were formed with the thermodynamically more stable compound 4 preponderating and recognized that this reaction is related to the Lobry de Bruyn -... 

Alkali or ammonium chloride can be removed from the reaction mixture by sedimentation of filtration. Ammonia as base is definitely preferable in case of M(IV) derivatives to help avoid formation of stable bimetallic alkoxide derivatives [59], while Ln(0 Pr)3 and M (OR)s, M = Nb, Ta can be obtained in best yields using KOR because the bimetallic species with K are least stable thermodynamically [84]. 

Allred GC, Woolley EM (1981) Heat capacities of aqueous acetic acid, sodium acetate, ammonia, and ammonium chloride at 283.15, 298.15 and 313.15 K AC for ionization of acetic acid and for dissociation of ammonium ion. J Chem Thermodynamics 13 155-164... 

Physical Properties. Sulfuryl chloride [7791-25-5] SO2CI2, is a colorless to light yellow Hquid with a pungent odor. Physical and thermodynamic properties are Hsted ia Table 7. Sulfuryl chloride dissolves sulfur dioxide, bromine, iodine, and ferric chloride. Various quaternary alkyl ammonium salts dissolve ia sulfuryl chloride to produce highly conductive solutions. Sulfuryl chloride is miscible with acetic acid and ether but not with hexane (193,194). 

Deoxy-a-D-ribosyl-l-phosphate 20, a key substrate in the preparation of 2 -deoxynucleosides, was stereoselectively prepared by crystallization-induced asymmetric transformation in the presence of an excess of ortho-phosphoric acid and tri( -butyl)amine under strictly anhydrous conditions (Scheme 2).7 Initial Sn2 displacement of Cl in ot-glycosyl chloride 16 by phosphoric acid resulted in a 1 1 a/p anomeric mixture of 17 and 18 due to the rapid anomerisation of the a-chloride in polar solvents. Under acidic conditions, in the presence of an excess of H3P04, an equilibration between the a and p anomers gradually changed in favour of the thermodynamically more stable a-counterpart. By selective crystallization of the mono tri( -butyl)ammonium salt of the a-phosphate from the mixture, the equilibrium could be shifted towards the desired a-D-ribosyl phosphate 18 (oc/p = 98.5 1.5), which was isolated as bis-cyclohexylammonium salt 19 and deprotected to furnish compound 20. 

Thermodynamic calculations for the composition containing 2% thiourea and 2% sodium chloride were made, and the theoretical flame temperature was found to be 2224° K. A series of measurements by the sodium line reversal method gave 2275 50° K. for the flame temperature. This is close enough agreement so that we feel that thermodynamic equilibrium is achieved in the flame, and the reaction products are as written above. This differs markedly from the results with ammonium perchlorate where a substantial fraction of the nitrogen was present as oxides of nitrogen even at elevated pressures (16). 

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