Trimethylamine hydrate

Trimethylamine hydrate, 4 (CH3)3N 41H20 + 5 Hydrogen-bonded in very distorted 15- and 26-polyhedra 12-Hedra (512)b 15-Hedra (5,2-63) 26-Hedra (S24 2)6... 

Girard s reagent T is carbohydrazidomethyltrimethylammonium chloride (I) and is prepared by the reaction of the quaternary ammonium salt formed from ethyl chloroacetate and trimethylamine with hydrazine hydrate in alco-hoUc solution ... 

Trimethylamine oxide is normally available as a hydrate, and for the present preparation it is necessary to convert it to its anhydrous form. A convenient way of doing this is as follows. A solution of 45.0 g. of trimethylamine oxide dihydrate (supplied by Beacon Chemicals) is dissolved in 300 ml. of warm dimethyl-formamide and placed in a three-necked flask set up for distillation. At atmospheric pressure the flask is heated and solvent distilled off until the boiling point reaches 152-153°. Then the pressure is reduced using a water aspirator, and the remainder of the solvent is distilled. At the end of the distillation the temperature of the bath is slowly raised to 120°. The residual anhydrous trimethylamine oxide (30 g.) can be dissolved in 100 ml. of chloroform and may remain in the same flask for use in the present preparation. 

Although this material contains a small amount of the symmetrical dihydrazide, which is not easily eliminated on crystallization, it is entirely satisfactory for use as a reagent for the isolation of ketones. A purer product, m. p. 192°, with decomposition, can be obtained by adding the solution prepared from ethyl chloroacetate and trimethylamine to an alcoholic solution containing a considerable excess of the hydrazine hydrate. 

At the same time the formaldehyde (as hydrate) is dehydrogenated yielding formic acid and COs. If the amount of aldehyde is increased trimethylamine hydrochloride is produced in an analogous manner. 

An X-ray liquid diffraction experiment on a solution corresponding to the stoichiometry of the trimethylamine decahydrate [807], 4(CH3)3N 40H2O, provided the radial distribution function shown in Fig. 21.14, which could be fitted equally well with models based on the hydrate crystal structure or on the ice I structure with interstitial amine molecules. This result clearly illustrates the insensibility of X-ray liquid diffraction data alone for distinguishing between competing models for aqueous solutions which have similar first- and second-order coordinations. 

McMullan RK, Jordan TH, Jeffrey GA (1967) Polyhedral clathrate hydrates, XII. The crystallographic data on hydrates of ethylamine, dimethylamine, trimethylamine, n-propylamine (two forms), isopropylamine, diethylamine (two forms) and tert-butylamine. J Chem Phys 47 1218-1222... 

Panke D (1968) Polyhedral clathrate hydrates, XV. Structure of trimethylamine decahydrate. J Chem Phys 48 2990-2996... 

What happens to the same reaction in aqueous solution Whereas the neutral reactants, ammonia and trimethylamine, are hydrated about equally well, the ammonium ion is hydrated much more strongly than is MejNH . As shown by Eqs. (4-21) and (4-22), solvation through hydrogen bonding will tend to increase the base strength of all amines... 

A mixture of 100 ml. of aqueous 33% trimethylamine solution and 600 ml. of 3% hydrogen peroxide is allowed to stand for 24 hours. If the odor of the amine is still apparent, another 100-200 ml. of hydrogen peroxide is added. After the amine odor has disappeared, the mixture is evaporated under vacuum and the residue is recrystallized from ethanol-ether mixture. The yield of trimethylamine oxide di-hydrate, m.p. 96°, is aroimd 95%. 

In general, the acetylenic triple bond is highly reactive toward hydrogenation, hydroboration, and hydration in the presence of acid catalyst. Protection of a triple bond in disubstituted acetylenic compounds is possible by complex formation with octacarbonyl dicobalt [Co2(CO)g Eq. (64) 163]. The cobalt complex that forms at ordinary temperatures is stable to reduction reactions (diborane, diimides, Grignards) and to high-temperature catalytic reactions with carbon dioxide. Regeneration of the triple bond is accomplished with ferric nitrate [164], ammonium ceric nitrate [165] or trimethylamine oxide [166]. 

To 2 ml of trimethylamine (33 per cent solution) add 13 ml of 3 per cent hydrogen peroxide. Cork, and let stand until the next laboratory period. Note whether any odor of amine remains. Evaporate to dryness on a water bath, and add 2 ml of alcohol. The crystals which separate out are the hydrate of trimethylamine oxide, (CH3)3N0-2 H O. 

Like the double bond, the carbon-carbon triple bond is susceptible to many of the common addition reactions. In some cases, such as reduction, hydroboration and acid-catalyzed hydration, it is even more reactive. A very efficient method for the protection of the triple bond is found in the alkynedicobalt hexacarbonyl complexes (.e.g. 117 and 118), readily formed by the reaction of the respective alkyne with dicobalt octacarbonyl. In eneynes this complexation is specific for the triple bond. The remaining alkenes can be reduced with diimide or borane as is illustrated for the ethynylation product (116) of 5-dehydro androsterone in Scheme 107. Alkynic alkenes and alcohols complexed in this way show an increased structural stability. This has been used for the construction of a variety of substituted alkynic compounds uncontaminated by allenic isomers (Scheme 107) and in syntheses of insect pheromones. From the protecting cobalt clusters, the parent alkynes can easily be regenerated by treatment with iron(III) nitrate, ammonium cerium nitrate or trimethylamine A -oxide. ° ... 

A final difference between amine oxides and phosphine oxides lies in the polarity of the molecules. The dipole moment of trimethylamine oxide is 16.7 X 10 C m (5.02 D) compared with 14.6 x 10 C m (4.37 D) for triethylphosphine oxide. A consequence of this polarity is the tendency of the amine oxides to form hydrates, R3NO H2O, and their greater basicity relative to the phosphine oxides. 

The acetoacetanilide 2 (2.00 mmol) was ground in an agate mortar. The solid diazonium nitrate hydrate (2.00 mmol) was added and co-ground in five portions for 10 min each to obtain 3 that was transferred to a 100-mL flask that was then evacuated. The salt was exposed to trimethylamine gas (0.5 bar) overnight at room temperature. After recovery of excess gas from a trap at 77 K the trimethy-lammonium nitrate was washed away with water (20 mL) and the pure residual 4 (664 mg, 100%, mp 273 °C) dried in vacuo. 

Tetramethyl ammonium hydrate—(CH,) N,OH—91. -This substance, whose constitution is similar to that of ammonium hydrate, is obtained by decomposing the corresponding iodide, (CHJ NI, formed by the action of methyl iodide upon trimethylamine. It is a cr -stalline solid deliquescent veiy soluble in H,0 caustic not volatile without decom-position. It attracts carbon dioxide from the air, and combines witli acids to form crystallizable salts. 

Figure 5.33 shows the change in transport number of sulfate ions relative to chloride ions with number of carbons in the alkyl ammonium groups. Contrary to />c,N0 Paso decreases with increasing number of carbons due to strong hydration of sulfate ions the effect is removed by the reaction of trimethylamine with the membranes. Similarly, the permeation of fluoride ions decreases with increasing number of carbons in the alkyl groups."... 

Ethyl chloroacetate (984 g) and well-cooled anhydrous trimethylamine (280 g) are dissolved in anhydrous ethanol (21). Next day, further trimethylamine (200 g) is added. On the third day hydrazine hydrate (400 g) is added in one portion with good stirring, and the mixture is kept in a refrigerator until the strongly exothermic reaction has ended. The material that has separated is collected with exclusion of moisture. A second crop is obtained by concentration of the mother liquor, giving a total yield of about 90% the m.p. is 192° (dec.). 

Trimethylamine oxide hydrate 176 A 33% aqueous solution (100 ml) of trimethylamine and a pure 3 % solution (600 ml) of hydrogen peroxide are allowed to react at room temperature. If the odor of trimethylamine has hot disappeared after 24 h, more hydrogen peroxide solution (100-200 ml) is added. When trimethylamine can no longer be detected, the solution is evaporated in a vacuum and the residue is recrystallized from ethanol-ether. This gives the oxide hydrate as needles, m.p. 96° in yields up to 95 %. 

Anhydrous trimethylamine oxide is obtained by removing the water from the hydrate at 120-150°/12 mm.176 Industrially, trimethylamine oxide hydrate is prepared at a lower temperature (—40°) than that mentioned above.177... 

Low-Temperature Decomposition. Over the range of 150°-275°C, a certain amount of intracrystalline water, whether physically adsorbed or hydrating the hydrogen ions, was present. The amount was minimized by pre-evacuating the sample at 150 °C. A displacement reaction of water nucleophile on the TTMA cations forming methanol, trimethylamine— and zeolite hydroxyl groups—can occur. 

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