Hydrate recrystallization

Hemi-hydrate recrystallized gypsum that is relatively pure, 0.2-0.4 percent total P205. This makes it more suitable for a cement additive or in wallboard. 

A solution of the 3-ketone hydrate (0.15 g) in acetone- -heptane is heated to boiling. After the acetone has been boiled off, a trace of concentrated hydrochloric acid is added to the -heptane solution and boiled for an additional 2 min. After cooling, the resulting crystals are collected by filtration, washed with dry -heptane and dried in vacuo overnight. Recrystallization from dry -heptane gives 17 -hydroxy-4,4-difluoroestr-5-en-3-one 0.98 g mp 123.5-124.5° [a] 134° (CHCI3). 

Alkylquinazolines are catalytically reduced to the corresponding 3,4-dihydro derivatives/ The only example of a 4-substituted quin-azoline which was reduced to its 3,4-dihydro derivative is 2-chloro-4-phenylquinazoline which gave 4-phenyl-3,4-dihydroquinazoline/ 4-Methylquinazolines are susceptible to oxidation, as is shown by the attempted nitration of 2,4-diraethylquinazoline which causes the removal of the methyl group with formation of 4-hydroxy-2-methyl-6-nitroquinazoline/ When the 4-substituent is —C(Et) (C02Et)2 recrystallization of the picrate from ethanol is sufficient to convert it to 4-hydroxyquinazoline/ Similar hydrolyses occur in acid solution and the mechanism undoubtedly involves a hydrated intermediate/... 

Cyclohexanone gives c-caprolactone, bp 102-10477 mm, which may polymerize on standing. The lactone may be converted easily to the corresponding e-hydroxy-hydrazide by heating on a steam bath with a slight excess of 100% hydrazine hydrate. The crude hydrazide may be recrystallized from ethyl acetate, mp 114-115°. 

The carbonyl compound to be reduced (0.1 mole) is placed in a 250-ml round-bottom flask with 13.5 g of potassium hydroxide, 10 ml of 85% hydrazine hydrate, and 1(X) ml of diethylene glycol. A reflux condenser is attached and the mixture is heated to reflux for I hour (mantle). After refluxing 1 hour, the condenser is removed and a thermometer is immersed in the reaction mixture while slow boiling is continued to remove water. When the pot temperature has reached 200°, the condenser is replaced and refluxing is continued for an additional 3 hours. The mixture is then cooled, acidified with concentrated hydrochloric acid, and extracted with benzene. The benzene solution is dried, and the benzene is evaporated to afford the crude product, which is purified by recrystallization or distillation. 

Chloro-2-hydrazino-4-phenylquinoline A stirred mixture of 2,6-dichloro-4-phenylquino-line 12.7 g,0.01 mol) and hydrazine hydrate (6.8 g) was refluxed under nitrogen for 1 hour and concentrated in vacuo. The residue was suspended in warm water, and the solid was collected by filtration,dried and recrystallized from ethyl acetate-Skelly B hexanes to give 1.81 g (67% yield) of 6[Pg.46]

A mixture of 10 parts of 7-chloro-4-fluorobutyrophenone, 5.5 parts of 1-(1,2,3,6-tetrahydro-4-pyridyl)-2-benzimidazolinone, 4 parts of sodium carbonate, and 0.1 part of potassium iodide in 176 parts of 4-methyl-2-pentanone is stirred and refluxed for 64 hours. The cooled reaction mixture is filtered and the solvent is evaporated from the filtrate to leave an oily residue which is dissolved in toluene. The toluene solution is filtered and the solvent is evaporated. The resultant residue is recrystallized from a mixture of 32 parts of ethyl acetate and 32 parts of diisopropyl ether to give 1-[1-[(4-fluorobenzoyl)propyll-1,2,3,6-tetrahydro-4-pyridyl]-2-benzimidazolinone hydrate melting at about 145°-146.5°C. 

The reaction mixture is then warmed on the steam bath for an additional two hours (90°C to 95°C). The excess hydrazine hydrate is removed in vacuo. The residue of viscous 1-hy-drazlno-3-morpholinyl-2-propanol Is not distilled, but is mixed with 10.16 g (0.0B6 mol) diethyl carbonate and a solution of 0.3 g sodium metal in 15 ml methyl alcohol. The mixture is refluxed about 2 hours under a 15 cm Widmer column, the alcohol being removed leaving a thick, green liquid residue, which is cooled and the precipitate which forms is removed by filtration and washed well with ether. Yield B2%, MP114°C to 116°C. Recrystallization from isopropanol gives purified 3-amino-5-(N-morpholinyl)-methyl-2-oxazolidone, MP 120°C as the intermediate. 

A mixture of 38.6 g (0.1 mol) of 3,4,3, 4 -tetramethoxy-6-(a-acetopropyl)-benzophenone, 5.5 g (0.11 mol) of 100% hydrazine hydrate or 3.52 g (0.11 mol) of hydrazine, and 500 ml of absolute ethanol is boiled for 5 hours. After adding 100 ml of benzene, 400 ml of solvent mixture Is distilled off from the reaction mixture by slow boiling for 3 hours. After cooling for 8 hours, 19 g of 5H-2,3-benzodiazepine derivative are separated from the residue as small, white crystals. The melting point is 133°C to 1 36°C (after recrystallizing from absolute ethanol, 136°C). 

The eluate was evaporated to dryness in vacio, leaving an amorphous residue of 113 mg of leurosine. The residue was treated with a few ml of methanol in which it quickly dissolved, but from which leurosine quickly precipitated in crystalline form. Because of the affinity of leurosine for water, and the presence of traces of water in the solvents, the leurosine was obtained in the form of its octahydrate. Although the material as obtained was substantially pure, it was further purified by recrystallizing it from hot methanol solution. The hydrated leurosine obtained decomposed at about 200° to 205°C. 

B. 2-Methylcyclopenlane-l,3,5-trione hydrate. A mixture of 200 g. (0.89 mole) of the keto ester prepared above, 910 ml. of water, and 100 ml. of 85% phosphoric acid is healed under reflux for 4 hours and then cooled in an ice-salt bath to —5°. The trione mixed with oxalic acid separates and is collected by filtration and dried under reduced pressure. The dried material is extracted with boiling ether (250-300 ml.) under reflux, and the ethereal extract is separated from the undissolved oxalic acid. The original aqueous filtrate is also extracted with ether in a continuous extractor. The two extracts are combined, and ether is removed by distillation. The crude trione separates as a dark brown solid and is crystallized from ca. 250 ml. of hot water. The once-crystallized, faintly yellow product weighs 95-105 g. (74-82%), m.p. 70-74°. This product is used in the next step without further purification. A better specimen, m.p. 77-78°, which is almost colorless, can be obtained by recrystallization from hot water after treatment with Norit activated carbon. 

The 1/7-2-benzopyran-l-one or 1/7-2-benzothiapyran-l-one (1.0 g) in EtOH (50 mL) containing hydrazine hydrate (2 mL, large excess) was heated under reflux for 2 h. The resulting solution was evaporated and the residue was recrystallized (EtOH). 

A mixture of 5,6-diamino-1,3-dimethylpyrimidine-2,4-(l//,3/f)-dione hydrate (5.0 g, 26.5 mmol), phthalic anhydride (7.9 g, 26.5 mmol) and A.A-dimethylaniline (60 mL) was heated tolux under N2 as H20 was removed using a Dean-Stark trap. After 1.5 h the mixture was cooled to rt and filtered. The resulting crude product was recrystallized from 95% F.tOH (800 mL) to give pale yellow needles yield 4.5 g (52%). An analytical sample was prepared by recrystallization (0.5 g in 300 mL of H20) as a hydrated solid mp > 250 C. 

Zinc adsorption can occur via exchange of Zn2+ and Zn(OH)+ with surface-bound Ca2+ on calcite (Zachara et al., 1988). Zinc and Ni form surface complexes on calcite as hydrate until they are incorporated into the structure via recrystallization (Zachara et al., 1991). The selectivity of metal sorption on calcite is as follows Cd > Zn > Ni (Zachara et al., 1991). The easily reducible oxide bound metals are primarily from Mn oxides (Chao, 1972 Shuman, 1982 and 1985a). At pH > 6, Zn sorption on Mn oxide abruptly increases because of hydroxylation of the ions (Loganathan et al., 1977), and a high soil pH in arid soil may favor Zn sorption on Mn oxides due to a great... 

The product crystallizing out of cooled methanol solutions appears to be an unstable methanol adduct of bis(2,4-pentanedionato)zinc. Recrystallization from hot alcohol yields the hydrate. Immediately after collection, this adduct melts at 80 to 90° on standing in the open atmosphere, it is converted into the hydrate. 

A fair number of mixed solvates, compounds containing molecules of crystallization of two different solvents, are also known. Generally, these are obtained either by recrystallizing halide hydrates from a nonaqueous solvent, or by crystallizing a halide from an appropriate solvent mixture, such as an alcohol intentionally or unintentionally containing significant amounts of water. Examples include... 

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