Solid filterable

Introduce 197 g. of anhydrous brucine or 215 g. of the air-dried dihydrate (4) into a warm solution of 139 g. of dZ-acc.-octyl hj drogen phthalate in 300 ml. of acetone and warm the mixture vmder reflux on a water bath until the solution is clear. Upon cooling, the brucine salt (dA, IB) separates as a crystalline solid. Filter this off on a sintered glass funnel, press it well to remove mother liquor, and wash it in the funnel with 125 ml. of acetone. Set the combined filtrate and washings (W) aside. Cover the crystals with acetone and add, slowly and with stirriug, a slight excess (to Congo red) of dilute hydrochloric acid (1 1 by volume about 60 ml.) if the solution becomes turbid before the introduction of... 

Method 1. Place 20 g. of crude benzoin (preceding Section) and 100 ml. of concentrated nitric acid in a 250 ml. round-bottomed flask. Heat on a boiling water bath (in the fume cupboard) with occasional shaking until the evolution of oxides of nitrogen has ceased (about 1 -5 hours). Pour the reaction mixture into 300-400 ml. of cold water contained in a beaker, stir well until the oil crystallises completely as a yellow solid. Filter the crude benzil at the pump, and wash it thoroughly with water to remove the nitric acid. RecrystaUise from alcohol or methylated spirit (about 2-5 ml. per gram). The yield of pure benzil, m.p. 94-96°, is 19 g. 

A solution of 3 (1.35 g, 4 rrtmol) in 2N MeONa (50 mL) was refluxed under N2 for 2 h. The cooled mixture was neutralized with dilute HCI, the solid filtered and washed with water. RecrystalCzation from AcOH afforded 4, mp 278-280 0. 

A solution of mercuric chloride (1.63 g) in ethanol (10 ml) and 38 % hydrochloric acid (1 ml) is added to a solution of the diene (2 g) in ethanol (20 ml) and water (1 ml), and the mixture is heated on the steam bath for 30 min. The ethylthiomercurichloride is filtered, washed with ethanol (5 ml) and dried, yield 96%. The filtrate is poured into water (150 ml) and the solid filtered, washed with water and crystallized from aqueous methanol, 4 1. After three crystallizations 41 % of 3, 21-dihydroxypregn-5-en-20-one is obtained mp 160-165° [a] 7° (CHCI3). 

To a solution of 970 parts of 2,6-dihydroxyacetophenone and 325 parts of epichlorohydrin in 1,500 parts of hot isopropanol was added, with stirring under reflux, a solution of 233 parts of 85% KOH in 2,500 parts of isopropanol and sufficient water (ca 100 parts) to dissolve the solid. The mixture was heated, with stirring, under reflux for 48 hours. Half the solvent was then distilled off and 5,000 parts of water were added. The mixture was cooled and the solid filtered off and washed with isopropanol and ether. It was then recrystallized from 12,500 parts of isopropanol to obtain a first crop of 380 parts and a second crop, after concentration, of 300 parts of 1,3-bis(2-acetyl-3-hydroxyphenoxy)-2-hydroxypropane. 

The supply of chlorine was then interrupted and the precipitated solid filtered off and dried. 

C) 4 -lodobutyl-3,4-Dimethoxybenzoate 32.5 g of 4 -chlorobutyl-3,4-dimethoxybenzoate and 19.5 g of sodium iodide (10% excess) were boiled in 150 ml of methyl ethyl ketone for 2.5 hours after cooling and filtering off the sodium chloride produced, the reaction was found not to be entirely completed boiling was then continued for another two hours the reaction mixture was cooled, and the solid filtered off and washed with 2 x 100 ml of ether. 

In another representative procedure about 2.3 mols of 2,6-di-tert-butyl-4-mercaptophenol is dissolved in about 1,700 ml of methanol under a nitrogen atmosphere about 100 ml of concentrated hydrochloric acid and 1B0 ml of acetone are added, and the mixture is stirred and maintainedat a temperature of about 35°C to 50°C, for 1.5 hours. The mixture is then cooled to room temperature and filtered, and the bis(3,5-di-tert-butyl-4-hydroxyphenyl) acetone mercaptole product is collected as a colorless crystalline solid filter cake. The product is washed with water and aqueous sodium bicarbonate and purified by recrystallization from ethanol. 

Best Preparation on a Laboratory and Commercial Scale. A. Methylene diform amide. In a 2fi round bottom 1 neck flask are placed 540g of formamide and 70g of hexamine. The flask is fitted with a wide bore air condenser topped with a w jacketed reflux condenser, and the flask held at 140 for 5 hours. It is chilled in ice, the solid filtered, and washed on the filter with 90g of formamide. The cmde prod may be used in the next step. For a pure sample,- the crude solid is dissolved in et ale, decolorized with charcoal, and the soln chilled, mp 142—43°... 

The stirring is contd for 5 hours, the pptd solid filtered off, and recrystd from w to give 8.4g of K dinitromethane, yield 23.3%, expln temp 208° (Ref 8). More recently it is conveniently prepd on a lab and comml scale by the interaction of NMe and Na nitrite with a Ag salt, most commonly the nitrate. This re- action, developed by Shechter and Kaplan of the Purdue Research Foundation, is called the Shechter-Kaplan reaction (Ref 14). The IR spectrum is given in Ref 13. The ionization constant in w at 25° is 2.26 0.01 (Ref 20). 

Ni(NH3 )6 (Cl04>2- Lavender crysts, prepd as follows to a soln of 23.8g of Ni dichloride and 5.4g of Amm chloride in 125ml of w is added 14.0g of Na perchlorate in 50ml of w, followed by the slow addn with stirring of 60ml of coned aq ammonia. The mixt is chilled for 4 hours in. an ice bath and the solid filtered to give 48% of the hexaammoniate which is free of chloride (Ref 11). It also can be prepd by treatment of an O-free aq soln of Ni perchlorate contg an... 

Preparation. It is prepd by dissolving pure Sr nitrate in an excess of perchloric ac, the excess ac neutralized with Sr carbonate, all solids centrifuged off, and the soln chilled until crysts appear (Ref 2). The anhyd salt can also be prepd by drying the hydrate at 250°, yield 50% (Ref 3) or the addn of anhyd perchloric ac to a soln of Sr ion in anhyd trifluoroacetic ac, the pptd solid filtered, and the excess acid removed in a vacuum (Ref 7)... 

Various extraction methods for phenolic compounds in plant material have been published (Ayres and Loike, 1990 Arts and Hollman, 1998 Andreasen et ah, 2000 Fernandez et al., 2000). In this case phenolic compounds were an important part of the plant material and all the published methods were optimised to remove those analytes from the matrix. Our interest was to find the solvents to modily the taste, but not to extract the phenolic compounds of interest. In each test the technical treatment of the sample was similar. Extraction was carried out at room temperature (approximately 23 °C) for 30 minutes in a horizontal shaker with 200 rpm. Samples were weighed into extraction vials and solvent was added. The vials were closed with caps to minimise the evaporation of the extraction solvent. After 30 minutes the samples were filtered to separate the solvent from the solid. Filter papers were placed on aluminium foil and, after the solvent evaporahon, were removed. Extracted samples were dried at 100°C for 30 minutes to evaporate all the solvent traces. The solvents tested were chloroform, ethanol, diethylether, butanol, ethylacetate, heptane, n-hexane and cyclohexane and they were tested with different solvent/solid ratios. Methanol (MeOH) and acetonitrile (ACN) were not considered because of the high solubility of catechins and lignans to MeOH and ACN. The extracted phloem samples were tasted in the same way as the heated ones. Detailed results from each extraction experiment are presented in Table 14.2. 

When separating solid particles from a liquid filtrate, if the solid filter cake is a product, rather than a waste, then it is usual to wash the filter cake to remove the residual filtrate from the filter cake. The washing of the filter cake after filtration takes place by displacement of the filtrate and by diffusion. 

Granular solid filters (see Fig. 16-4) are cleaned by backwashing with water. The backwashing is usually preceded by an air scouring to assure better cleaning.30 The backflow water rate should be fast enough to fluidize the bed. 

Inulin Acetate. Stir 100 g. of inulin in 1,000 ml. of pyridine at 80° for forty-five minutes. Cool, while continuing the stirring, and to the clear solution add dropwise 180 ml. of acetic anhydride. After six hours more of stirring, pour the clear solution into 10 liters of water. The inulin acetate separates as a white solid. Filter and wash repeatedly with distilled water to remove the pyridine and acetic anhydride. Purify the dried crude product by dissolving in ten times its weight of hot methyl alcohol and filtering. Inulin acetate separates from the cold solution as a fine white powder [ajj20 = — 34° (c = 1.5, chloroform), [o ]d20 = — 43° (c = 1.8, acetic acid). 

The washing of filter cake is carried out to remove liquid impurities from the valuable solid filter cake or to increase the recovery of valuable filtrate. Wake-man (1990) has shown that the axial dispersion flow model, as developed in... 

Analyze Filter solid Filter solid Filter solid 1... 

An oven-dried flask, with a septum capped nitrogen inlet, was charged with a solution of (G = —0.5) dendn-PAMAM(C02Me)4 [J ] precursor (2.5 g, 6.2 mmol) in anhydrous dimethyl sulfoxide (10 ml). A mixture of Tris (tri-hydroxymethyl aminoethane) (3.76 g, 0.031 mol) and anhydrous potassium carbonate (2.7 g, 0.031 mol) was added to the suspension. The solution was heated in a paraffin oil bath maintained at 40°C for 96 h. After filtration the excess solvent was removed by vacuum pump (10 1 mm Hg, 50°C). The resulting thick, white oil was dissolved in a minimum quantity of distilled water and precipitated with propanone. The suspension was cooled in the freezer, and the solid filtered and dried in a vacuum oven (10 1 mm Hg, 40 °C) to give the hygroscopic terminated dendrimer as a white powder (4.5 g, 95%). 

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