Watering wisely

Water wisely. Water is especially important in the development of bacterial and fungal diseases. Many soilborne fungal diseases become a problem in soils that are too wet. 

A 1500 ml. flask is fitted (preferably by means of a three-necked adaptor) with a rubber-sleeved or mercury-sealed stirrer (Fig. 20, p. 39), a reflux water-condenser, and a dropping-funnel cf. Fig. 23(c), p. 45, in which only a two-necked adaptor is shown or Fig. 23(G)). The dried zinc powder (20 g.) is placed in the flask, and a solution of 28 ml. of ethyl bromoacetate and 32 ml. of benzaldehyde in 40 ml. of dry benzene containing 5 ml. of dry ether is placed in the dropping-funnel. Approximately 10 ml. of this solution is run on to the zinc powder, and the mixture allowed to remain unstirred until (usually within a few minutes) a vigorous reaction occurs. (If no reaction occurs, warm the mixture on the water-bath until the reaction starts.) The stirrer is now started, and the rest of the solution allowed to run in drop-wise over a period of about 30 minutes so that the initial reaction is steadily maintained. The flask is then heated on a water-bath for 30 minutes with continuous stirring, and is then cooled in an ice-water bath. The well-stirred product is then hydrolysed by the addition of 120 ml. of 10% sulphuric acid. The mixture is transferred to a separating-funnel, the lower aqueous layer discarded, and the upper benzene layer then... 

Example. Dissolve 0 3 g. of />-chlorobenzoic ncid in a small quantity of warm ethanol (about 10 ml.), and ctlrefully add 5 o aqueous sodium hydroxide drop- wise until the solution is just pink to phenolphthalein. Evaporate to dryness on a water-bath. Dissolve the sodium -chlorobenzoate in a minimum of water, add a solution of 0-5 g. of phenacyl bromide in ethanol (about 5 ml.), and boil the mixture under reflux for i hour, and then cool. The phenacyl ester usually ciy stallises on cooling if it does not, add water dropnise with stirring to the chilled solution until separation of the ester just begins. Filter the ester, wash on the filter with water, drain and recrystallise from ethanol m.p. 90 . The /)-bromophenacyl ester is similarly prepared, and after recrystallisation from aqueous ethanol has m.p. 128 . (M.ps., pp. 543-545.)... 

The experimental conditions necessary for the preparation of a solution of a diazonium salt, diazotisation of a primary amine, are as follows. The amine is dissolved in a suitable volume of water containing 2 5-3 equivalents of hydrochloric acid (or of sulphuric acid) by the application of heat if necessary, and the solution is cooled in ice when the amine hydrochloride (or sulphate) usually crystallises. The temperature is maintained at 0-5°, an aqueous solution of sodium nitrite is added portion-wise until, after allowing 3-4 minutes for reaction, the solution gives an immediate positive test for excess of nitrous acid with an external indicator—moist potassium iodide - starch paper f ... 

To a mixture of 100 ml of THF and 0.10 mol of the epoxide (note 1) was added 0.5 g Of copper(I) bromide. A solution of phenylmagnesium bromide (prepared from 0.18 mol of bromobenzene, see Chapter II, Exp. 5) in 130 ml of THF was added drop-wise in 20 min at 20-30°C. After an additional 30 min the black reaction mixture was hydrolysed with a solution of 2 g of NaCN or KCN and 20 g of ammonium chloride in 150 ml of water. The aqueous layer was extracted three times with diethyl ether. The combined organic solutions were washed with water and dried over magnesium sulfate. The residue obtained after concentration of the solution in a water-pump vacuum was distilled through a short column, giving the allenic alcohol, b.p. 100°C/0.2 mmHg, n. 1.5705, in 75% yield. 

In the flask were placed 40 ml of ethanol, 10 ml of water, 12 g of finely powdered CuCN and 0.40 mol of 3-bromo-l-butyne (compare VIII-2, Exp. 3). The mixture was warmed to 55°C and a solution of 26 g of KCN in 60 ml of water was added drop-wise or in small portions care was taken that complete dissolution of the copper cyanide did not occur (note 2). The temperature of the mixture was maintained close to 60°C throughout the period of addition. The conversion was terminated... 

R. M. RoweU and W. B. Banks, Water Kepelkng and Dimensional Stability of Wood, General Technical Report FPL 50, U.S. Department of Agriculture, Forest Service, Forest Products Laboratory, Madison, Wise., 1985. 

Certain conditions, ultimately dictated by economics, make the substitution of more resistant materials a wise choice. Stainless steels (not sensitized) of any grade or composition do not form tubercles in oxygenated water neither do brasses, cupronickels, titanium, or aluminum. However, each of these alloys may suffer other problems that would preclude their use in a specific environment. 

As we stated earlier, the moleeular weight advaneement in phenolies oeeurs through a step-wise eondensation proeess. Depending on the intermediates involved the moleeule eondensed out of the strueture may be either water or formaldehyde. An overview of this proeess was provided in Seheme 3. 

A solution of 1 g of the ethyleneketal of the trione in 40 ml of methanol is treated with 0.2 g of sodium borohydride and the mixture is stirred at 20° for 2 hr. Slow drop wise addition of water precipitates the reaction product as crystals. These are filtered, washed with water and dried, to give 1.02 g of hydroxy ketone, which after crystallization from methylene dichloride-hexane has mp 182-184° (reported 184-186°) -23° (CHCI3). 

A solution of sodium methoxide, prepared from sodium (23 g) and dry methanol (500 mL), was added drop-wise at 0 °C to a stirred suspension of aminoacetonitrile hydrochloride (18, 100 g, 1.08 mol) in dry methanol (100 rnL). After stirring for 2 h at rt the precipitated sodium chloride was filtered off and the filtrate concentrated in vacuo. EtOAc (20 mL) was added and evaporated under reduced pressure to remove all traces of methanol. The oily residue was dissolved in dry EtOAc (100 mL) and anhydrous sodium sulfate added. After cooling, the precipitate was filtered off. The solution of crude aminoacetonitrile was used without further purification. This solution was added drop-wise during a period of 1 h to a vigorously stirred, ice-cooled solution of carbon disulphide (100 mL, 1.66 mol) in dry EtOAc (100 mL) under an N2 atmosphere. Continued mechanical stirring and water-free conditions were essential. The mixture was stirred at 0 °C for 1 h. The resultant precipitate was filtered off, washed with EtaO and dried, giving the product 50 as yellow crystals (99 g, 75 % on amount of sodium), m.p. 131 °C dec. IR (KBr) v max 1630, 1500 cm. ... 

A solution of 11.2 g of potassium permanganate in 100 ml of warm water was added drop-wise to a well stirred solution of 10 g of 2-(4-chlorophenyl)-3-methyl-4-metathiazanone in 50 ml of glacial acetic acid. The temperature was kept below 30°C with external cooling. An aqueous sodium bisulfite solution was then added to remove the manganese dioxide. The thick whitish oil which separated was taken up in chloroform and the extract was washed with water. Removal of the chloroform by distillation in vacuo yielded an oily residue which solidified. The solid was recrystallized from isopropyl alcohol to give 5 g of the product, 2-(4-chlorophenyl)-3-methyl-4-metathiazanone-1,1-dioxide, MP 116.2° to 118.6°C (corr.). 

To a mixture of 4.1 parts of 4-piperidinopiperidine-4-carboxamide, 6.4 parts of sodium carbonate, and a few crystals of potassium iodide in 100 parts of anhydrous toluene is added drop-wise a solution of 5.6 parts of 7-chloro-4-fluorobutyrophenone and 40 parts of anhydrous toluene at a temperature of 30°C to 40°C. The mixture is stirred and refluxed for 48 hours. The reaction mixture is cooled and divided between 50 parts of water and 60 parts of chloroform. The combined organic layers-toluene and chloroform-are dried over potassium carbonate, filtered, and evaporated. The oily residue solidifies on treatment with 80 parts of ether. After cooling for 30 minutes at 0°C, there is obtained 1 -[7-(4-fluorobenzoyl)propyl] -4-pi-peridinopiperidine-4-carboxamide melting at about 1 24.5°C to 126°C. 

Solders are anodic to copper, but soldered joints in copper pipes are widely used without trouble for cold supply waters possibly corrosion is restricted by the deposition of cathodic carbonate scales and the formation of insoluble lead compounds. Hot supply waters tend to be more aggressive and, where these are involved, it is wise to tin any copper which has a soldered joint. Electrolytes of high conductivity such as sea-water will also attack soldered joints in copper. 

In general it is wise to avoid as far as possible, the use of incompatible metallic joints in marine and offshore practice, since these are often in contact with seawater or water that contains chlorides which are effective corrosive electrolytes. It is prudent to take very considerable precautions to prevent corrosion at the design and installational stages. However, the widely diverse properties required of the materials used in such installations make it impracticable to avoid all such joints. 

To the cooled mixture 6N hydrochloric acid is added drop wise with stirring, until no solid remains. The organic layer is separated, washed four times with 30-ml. portions of water (Note 6), dried over powdered calcium chloride (Note 7), and distilled through a 1 X 15 cm. column packed with Fenske helices (Note 8). The yield of benzene is 5.5-6.5 g. (70-83%), b.p. 80-82°, n20d 1.5007. The fraction boiling at 82-180° contains no unreacted chlorobenzene (Notes 9, 10, 11). 

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