Dean-Stark water separator

A. 0-Methyl-ls -2-octalone id,lA-Dimethylhydra2one. A 250-ml., round-bottomed flask equipped with a magnetic stirring bar and a Dean-Stark water separator is maintained under a dry nitrogen atmosphere (Note 1) and eharged with 7.4 g. (0.045 mole) of 10-methyl-A -2-oetalone [2(3 f)-Naphthalenone, 4,4a,5,6,7,8-hexahydro-4a-methyl-] (Note 2), 9.0 g. (0.15 mole) of N,N-dimethylhydrazine, 150 ml. of dry benzene, and 0.02 g. of p-toluenesulfonie aeid. This mixture is refluxed for 10-14 hours, after whieh time no further water separates. Benzene and excess N,A -dimethylhydrazine are then removed by simple distillation, and the residue is distilled under reduced pressure to give 8.1 g. (87%) of the dimethylhydrazone as a pale-yellow liquid, b.p. 94-98 (0.2 mm.) (Notes 3, 4). 

In general, base-catalyzed reactions of aromatic aldehydes with nitroalkanes give nitroalkenes directly (Knoevenagel reaction).54 The reaction is very simple heating a mixture of aromatic aldehydes, nitroalkanes, and amines in benzene or toluene for several hours using a Dean-Stark water separator gives the desired nitroalkenes in good yield, as shown in Eqs. 3.31-3.34.54-58... 

A. 1-Pyrrolidinocyrtohexene.2 3 A solution of 29.4 g. (0.3 mole) of cyclohexanone and 28.4 g. (0.4 mole) of pyrrolidine in 150 ml. of benzene is placed in a 500-ml., one-necked flask to which a Dean-Stark water separator is attached. The solution is refluxed under a nitrogen atmosphere until the separation of water ceases (Note 1). The excess pyrrolidine and benzene are removed from the reaction mixture on a rotary evaporator. The resulting residue is stored under refrigeration and distilled just before use in the next step to provide 44.6 g. of 1-pyrrolidinocyclohexene, b.p. 76-77° (0.5 mm.), 105-106° (13 mm.). 

FIGURE 3.19 Dean-Stark water separator. Water is removed from the reaction medium by covaporization with benzene. 

A. N-Benzylideneheneeneaulfonam-fAe. A 3-L, one-necked, round-bottomed flask is equipped with a mechanical stirrer (Note 1), Dean-Stark water separator (Note 2), double-walled condenser attached to an argon gas inlet and outlet needle connectors through a mineral oil bubbler. Into the flask are... 

A Dean-Stark water separator equipped with a Teflon stopcock for water removal was used. 

A. N-Benzylidenemethylamine. A solution of 31.9 g. (0.3 mole) of benzaldehyde in 80 ml. of benzene contained in a 300-ml. round-bottomed flask is cooled to approximately 10°. To this is added a solution of 14 g. (0.45 mole) of anhydrous methylamine in 50 ml. of benzene (Note 1). On standing, the solution becomes warm and turns milky. After 1 hour the flask is connected to a Dean-Stark water separator 1 which is attached to a reflux condenser, and the solvent is caused to reflux until no more water separates (Note 2). The water separator is then replaced by an 8-in. Vigreux column (Note 3), and the solution is distilled under reduced pressure. After removal of the solvent, the product distils at 92-93°/34 mm. The yield is 31-34 g. (87-95%) of colorless liquid, d5 1-5497, tt 1.5528. 

The water separator preferred by the submitter is that described by Wideqvist,2 but any continuous water separator which will return the benzene to the reaction mixture may be used, e.g., the modified Dean-Stark water separator. ... 

A 1-1., three-necked, round-bottomed flask is fitted with a mechanical stirrer, a reflux condenser attached to a Dean-Stark water separator, and a 250-ml. dropping funnel. The flask is charged with 25.0 g. (0.16 mole) of 3,7-dimethyl-6-octenal (Note 1) and 500 ml. of toluene. The solution is heated to reflux with stirring, and a solution of iV-methylhydroxylamine, methanol, and toluene is added (see below). 

A. Ethyl fi-Pyrrolidinocrotonate. Ethyl acetoacetate (130 g., 1.0 mole) (Note 1) and pyrrolidine (71 g., l.Omole) are dissolved in 400 ml. of benzene and placed in a 1-1. one-necked flask fitted with a Dean-Stark water separator on top of which is a condenser fitted with a nitrogen inlet tube. The reaction mixture is placed under a nitrogen atmosphere (Note 2) and then it is brought to and maintained at a vigorous reflux for 45 minutes, at which time the theoretical amount of water (18 ml.) has been collected. The benzene is then removed with a rotary evaporator. The residual ethyl /9-pyrrolidinocrotonate is highly pure and may be used without distillation (Note 3) yield 180 g. (98%). 

S. (-)-(Camphorsulfonyl)imine. A 1 -L, round-bottomed flask is equipped with a two-inch egg-shaped magnetic stirring bar, a Dean-Stark water separator, and a double-walled condenser containing a mineral oil bubbler connected to an inert gas source. Into the flask are placed 5 g of Amberylst 15 ion exchange resin (Note 4) and 41.5 g of the crude (+)-(1 S)-camphorsulfonamide in 500 mL of toluene. The reaction mixture is heated at reflux for 4 hr. After the reaction flask is cooled, but while it is still warm (40-50°C), 200 mL of methylene chloride is slowly added to dissolve any (camphorsulfonyl)imine that crystallizes. The solution is filtered through a 150-mL sintered glass funnel of coarse porosity and the reaction flask and filter funnel are washed with an additional 75 mL of methylene chloride. 

For the purposes of this method, a soil/sediment sample is defined as a portion of wet soil/sediment which does not contain oil, but which may contain other solids such as stones, vegetation, etc. The sample should not contain an obvious liquid phase (see Section 8.4). A 10 g aliquot of the soil/sediment sample is spiked with the internal standard solution and extracted with toluene in a combination of a Soxhlet extractor and a Dean Stark water separator (SDS). 

For the purposes of this method, a chemical waste sample includes sample matrices of oils, stillbottoms, oily sludge, oil-laced soil, and surface water heavily contaminated with the matrices listed above (see Section 8.2). Internal standards are added in the concentrations listed in Table 4 to a 1 or 10 g aliquot of chemical waste. Wet fuel oil and oily sludge samples, showing signs of water, are spiked with the internal standard solution, fitted with a reflux condenser and a Dean Stark water separator to remove the water, and extracted with toluene. Stillbottom samples are spiked with the internal standard solution, refluxed with toluene, and filtered. 

Dean Stark Water Separator Apparatus, with a Teflon stopcock. Must fit between Soxhlet extractor body and condenser. 

Four types of extraction procedures are employed in these analyses depending on the sample matrix. Chemical waste samples are extracted by refluxing with a Dean Stark water separator. Fly ash samples and soil/sediment samples are extracted in a combination of a Soxhlet extractor and a Dean Stark water separator. Water samples are filtered and then the filtrate is extracted using either a separatory funnel procedure or a continuous liquid-liquid extraction procedure. The filtered particulates are extracted in a combination of a Soxhlet extractor and a Dean Stark water separator. 

Oily Sludge/Wet Fuel Oil. Weigh about 1 g of sample to two decimal places into a tared preextracted 123-mL flask. Add 1 mL of the acetone-diluted internal standard solution (see Section 3.12) to the sample in the flask. Attach the preextracted Dean Stark water separator and condenser to the flask, and extract the sample by refluxing it with 30 mL of toluene for at least three hours. 

The practical utility of the facile addition of mercaptoacetic acid across the double bond of an azomethine has been used in the synthesis of thiazolo-triazolothiadiazin-6(7//)-one (328). Thus, 7//-3-methyl-5-triazolo[3,4-f>]thiadiazine hydrochloride (327), obtained by reacting l-amino-2-methyl-j-triazolyl-2-thione (326) with chloroacetaldehyde di-ethylacetal, reacts with mercaptoacetic acid in the presence of p-toluenesulfonic acid in boiling anhydrous benzene for 40 hr using a Dean-Stark water separator followed by basification with sodium bicarbonate to furnish 8a//,9//-3-methylthiazolo[3,2-u]-[l,3,4]triazolo(3,4-f>](1,3,4]-thiadiazin-6(7//)-one (328) (74IJC287) (Scheme 77). The absorption at 1725 cm (lactam carbonyl) in product 328 supports the cyclic structure in preference to the open-chain acid structure. 

N-Methyl-N-p-phenathylamine (4).3 Benzaldehyde 1 (116 g, 1.1 mol), p-phenetylamine (121 g, 1 mol) and PhMe (500 mL) were refluxed wHh a Dean-Stark water separator untiS all walsr had distHted. Under stirrmg, dimathyt sulfate (126 g, 1 mol) was added dnopwise and reflux was continued for another 3 h. Water and NaOH was added until the pH slabiRzed at pH-7. After hydrolysis, the solvent and 1 was recovered by steam distMation. The residual water tokilion was made alkaline to give 114 g of 4 (80-85%), bp 203 C, n -1.5162, d - 0.930. 

Cyclohexylidene derivatives of 1,2-diob. Whereas 1,2-diols had traditionally been characterized by reaction with acetone to produce the acetonide or isopropylidene derivatives, Micovic and Stojiljkovic recommended conversion of sugars and other polyols into their cyclohexylidene derivatives because of the ease with which these substances crystallize. Angyal et al. explored the behavior of inositol (1) and found that this cyclitol gradually dissolved in a mixture of cyclohexanone and benzene containing p-toluenesulfonic acid on boiling under a Dean-Stark water separator. 

The olefinic aldehyde 6a (58 mg, 0.26 mmol) and 4-toluenesulfonohydrazide in dry benzene (25 mL) was placed in a 5-mL flask equipped with a Dean-Stark water separator. The mixture was refluxed under dry Nj for 5 min. The solvent was removed and replaced by dry THF (2.5 mL) and 2 M BuLi in hexane (0.13 mL, 0.26 mmol) was added to the stirred solution. After 30 min the solvent was removed and the residual lithium salt of the tosylhydrazone 6b was heated slowly under reduced pressure (0.25 Torr). Between 120°C and 140°C the 4,5-dihydro-3/f-pyrazole 7 was collected as a colorless oil yield 50 mg (81% based on the aldehyde) nl 1.5042 [a] -I-95 (c = 1.0, CHCI3). A solution of the 4,5-dihydro-3i/-pyrazole 7 in Et20 (35 mL) was irradiated in a Rayonet reactor using 3500 A lamps and a Pyrex filter for 1 h. Removal of the solvent followed by distillation (airbath temperature, 80 °C) of the residual oil under reduced pressure (0.3 Torr) afforded pure (— )-cyclocopacamphene (8) yield 30 mg (93%) [a]o — 42 (c = 1.1, CHCI3). 

Morpholinomethyl)acrylonitrile (8).5 To cyanoacetic acid 5 (25.5 g, 0.3 mmol), paraformaldehyde 6 (21.6 g, 0.72 mmol) in PhH (150 mL) was added morpholine 7 (26.1 g, 0.3 mmol). After 6 h reflux with a Dean-Stark water separator, the solvent was evaporated, the residue was dissolved in CHCI3 and the organic phase was washed with water. Evaporation of the solvent and distillation afforded 36.5 g of 8 (80%), bp 142°C/25 Torr. 

Dialkyltin Compounds. All of the dialkyltin dimercaptides and dicarboxylates were prepared by reaction of the appropriate dialkyltin oxide (Alfa Inorganics) with the desired mercaptan or carboxylic acid. The reactions were carried out in refluxing benzene or toluene using a Dean-Stark water separator. The yields are quantitative and products require no purification (purity confirmed by H and 13C NMR). The dialkyltin dichlorides were obtained commercially (Alfa Inorganics) and used as received ... 

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