Product solution concentration

The required membrane area for a given capacity plant can be calculated from the current density in a stack that again depends on feed and product solution concentration. It can be calculated for a solution containing a single monovalent salt such as NaCl from the total current passing through the stack which is given by ... 

If the reaction rate is slow compared to the mixing rate, the reactants can be dispersed throughout the vessel before they react. The resulting product solution concentration will be more uniform throughout the vessel. The operation could be thought of as being determined by crystallization parameters rather than the reaction rate. 

Here Amin is the minimum membrane area required for a certain plant capacity and feed and product solution concentrations, a is a constant for a given plant design and operating mode, z is the chemical valence, F the Faraday constant, Q the product solution volume, and Cq and Cd the feed and the product solution concentrations. 

The hafnium product solution concentration depends upon the flow rate of sulphuric acid. When this is reduced to a low figure, the hafnium con-... 

At a constant applied pressure, increasing the feed solute concentration increases the product solute concentration. This is caused by the increase in the feed osmotic pressure, since as more solvent is extracted from the feed solution (as water recovery increases), the solute concentration becomes higher and the water flux decreases. Also, the amount of solute present in the product solution increases because of the higher feed concentration. 

Completion of crystallization Product solution concentrations are determined before and after crystallization. ... 

Dissociation of the second proton is insignificant. The pH of its aqueous solutions can be measured reproducibly with a glass electrode, but a correction dependent on the concentration must be added to obtain the tme pH value. Correction values for the most common commercial solutions are Hsted in Table 3. The apparent pH of commercial product solutions can be affected by the type and amount of stabilizers added, and many times the pH is purposely adjusted to a grade specification range. 

Color. The visual color, from white to dark brown, of sugar and sugar products is used as a general indication of quaUty and degree of refinement. Standard methods are described for the spectrophotometric deterrnination of sugar color that specify solution concentration, pH, filtration procedure, and wavelength of deterrnination. Color or visual appearance may also be assessed by reflectance measurements. 

Sulfide Solution Concentration. Tire by-product of the black ash process has considerable bearing on the ultimate economic viabiUty of barium production. It is desirable to be able to vary by-products to rnaxiaiize earnings. Sodium sulfide [1313-82-2 Na2S, sold as 60% flake, and sodium bisulfide [16721-80-5] NaHS, sold as 45% solution or as 70% flake, are t)-q)ically co-produced. 

There are 10 producers of calcium chloride solutions in the United States, three of these also make a dry product. Solution production is centered around Michigan (brines), California and Utah (brines), and Louisiana (by-product acid). The majority of dry calcium chloride is made in Michigan, lesser quantities in Louisiana, and minor quantities in California. Production involves removal of other chlorides (primarily magnesium) by precipitation and filtration followed by concentration of the calcium chloride solution, either for ultimate sale, or for feed for dry product. Commercial dry products vary by the amount of water removed and by the nature of the drying equipment used. Production and capacity figures for the United States are indicated in Table 2. 

Concentration. The concentration of fmit juice requites removal of solvent (water) from the natural juice. This is commonly done by evaporation, but the derived juices may lose flavor components or undergo thermal degradation during evaporation. In freeze concentration, solvent is crystallized (frozen) in a relatively pure form to leave behind a solution with a solute concentration higher than the original mixture. Significant advantages in product taste have been observed in the appHcation of this process to concentration of certain fmit juices. 

Now, the change in mass will be the product of concentration and change in volume thus, the change of mass of solute (dm) in plate (p) will be... 

The first two categories, clarifying and crossflow filters, have been very well developed and optimized for use in biotechnology and standard wastewater treatment applications. Equipment is easily available for these applications, whether as small 0.2 micron sterilizing filter used to terminally sterilize 100 ml of product solution, or a small 500 ml crossflow filter used to concentrate a small amount of antibody solution. Many vendors of this equipment to wastewater treatment applications have their origins in the CPI (Chemical Process Industries), and have incorporated many of the scale-up and optimization properties developed in much larger units used in large scale chemical production. As a result, these two filtration unit operations are one of the most optimized and efficient used in wastewater treatment. 

A major disadvantage of this system is the limitation of the single-pass gas-chlorination phase. Unless increased pressure is used, this equipment is unable to achieve higher concentrations of chlorine as an aid to a more complete and controllable reaction with the chlorite ion. The French have developed a variation of this process using a multiple-pass enrichment loop on the chlorinator to achieve a much higher concentration of chlorine and thereby quickly attain the optimum pH for maximum conversion to chlorine dioxide. By using a multiple-pass recirculation system, the chlorine solution concentrates to a level of 5-6 g/1. At this concentration, the pH of the solution reduces to 3.0 and thereby provides the low pH level necessary for efficient chlorine dioxide production. A single pass results in a chlorine concentration in water of about 1 g/1, which produces a pH of 4 to 5. If sodium chlorite solution is added at this pH, only about 60 percent yield of chlorine dioxide is achieved. The remainder is unreacted chlorine (in solution) and... 

The oxygen is then replaced by nitrogen and a solution of sodium hydroxide (5 g) in methanol (100 ml) and water (50 ml) is added. After agitation for 70 min at ambient temperature, followed by the addition of acetic acid (10 ml), the mixture is poured into water (4 liters). The precipitate is isolated by filtration, washed with water and dried in an air draft at 100° to yield 47 g of crude product. This material is dissolved in methanol (1.5 liters) and ethyl acetate (500 ml) and the solution concentrated to half its initial volume. Ethyl acetate (500 ml) is added and the solution is cooled to yield 29.4 g (63%) of 3, 17a-dihydroxy-16f -methyl-5a-pregnan-20-one mp 255-260° [ajp 45.6° (diox.). 

The solution of waste products is concentrated and stored in double-walled, stainless steel tanks shielded by a metre or more of concrete. 

The solid material Is separated by filtration and the chloroform solution concentrated to an oil under reduced pressure. The oil is dissolved in 50 ml of trichloroethylene, the solution treated with charcoal, filtered and the filtrate added to 125 ml of hexane. The crystalline material which forms on standing at refrigerator temperature is removed by filtration, washed with light petroleum ether and dried at about 50°C. Approximately 20 g of product are obtained. On recrystaliizing from trichloroethylene-hexane, 17.8 g of purified compound are obtained, (VIP 89° to 91°C. 

The acetic acid mother liquor, containing the rest of the reaction product, was concentrated in vacuo. The residue was dissolved in methylene chloride and washed with ice cold sodium carbonate solution. The organic solution was dried, concentrated in vacuo to a small volume and diluted with ether and petroleum ether. Fine yellow needles of 2-chloro-methyl-4-phenyl-6-chloroquinazoline 3-oxide precipitated. The pure base was recrystallized from a mixture of methylene chloride, ether and petroleum ether, MP 133° to 134°C. 

B) Preparation of 7-Chloro-3-Methoxycarbony/-5-Phenyl-2-0xo-2,3-Dihydro-iH-Benzo [fl-1,4-Diazepine (4347 CB) A solution of 9.2 g (0.04 mol) of compound 4356 CB in 20 ml of methanol is added dropwise, in the course of one hour and 30 minutes, to a boiling solution of 9.2 g (0.05 mol) of the hydrochloride of methyl aminomalonate in 30 ml of methanol. When this is completed, heating under reflux is continued for 30 minutes and the product then concentrated to dryness under reduced pressure. The residue is taken up in water and ether, the ethereal layer separated, the product washed with water and dried over sodium sulfate. The solvent is evaporated under reduced pressure. The residue, which consists of the methyl ester, could not be obtained in the crystalline state. It is dissolved in 25 ml of acetic acid, heated under reflux for 15 minutes, the product evaporated to dryness and the residual oil taken up in ether. A colorless solid separates which... 

In the final production preparation, a mixture of ethyl methyl(3-benzoylphenyl)cyano-acetate (48 g), concentrated sulfuric acid (125 cc) and water (125 cc) is heated under reflux under nitrogen for 4 hours, and water (180 cc) is then added. The reaction mixture is extracted with diethyl ether (300 cc) and the ethereal solution is extracted with N sodium hydroxide (300 cc). The alkaline solution is treated with decolorizing charcoal (2 g) and then acidified with concentrated hydrochloric acid (40 cc). An oil separates out, which is extracted with methylene chloride (450 cc), washed with water (100 cc) and dried over anhydrous sodium sulfate. The product is concentrated to dryness under reduced pressure (20 mm Hg) to give a brown oil (33.8 g). 

A mixture of 1B g of 1 -acetamido-3,5-dimethvladamantane, 3B g of sodium hydroxide, and 300 ml of diethylene glycol was refluxed for a period of 6 hours. The reaction product mixture was cooled and poured onto about IfiQQ ml of crushed Ice. The basic solution thus obtained was extracted five times with 250-ml portions of benzene and the aqueous layer was discarded. The combined benzene extracts were dried over sodium hydroxide and the dried benzene solution concentrated in vacuo to give a crude oil weighing 14 g and having np =... 

A mixture of 4.98 g of acetoacetic acid N-benzyl-N-methylaminoethyl ester, 2.3 g of aminocrotonic acid methyl ester, and 3 g of m-nitrobenzaldehyde was stirred for 6 hours at 100°C in an oil bath. The reaction mixture was subjected to a silica gel column chromatography (diameter 4 cm and height 25 cm) and then eluted with a 20 1 mixture of chloroform and acetone. The effluent containing the subject product was concentrated and checked by thin layer chromatography. The powdery product thus obtained was dissolved in acetone and after adjusting the solution with an ethanol solution saturated with hydrogen chloride to pH 1 -2, the solution was concentrated to provide 2 g of 2,6-dimethyl-4-(3 -nitrophenyl)-1,4-dihydropyridlne-3,5-dicarboxylic acid 3-methylester-5- -(N-benzyl-N-methylamino)ethyl ester hydrochloride. The product thus obtained was then crystallized from an acetone mixture, melting point 136°Cto 140°C (decomposed). 

Nylon 66 is produced by the reaction of hexamethylenediamine and adipic acid (see Chapters 9 and 10 for the production of the two monomers). This produces hexamethylenediammonium adipate salt. The product is a dilute salt solution concentrated to approximately 60% and charged with acetic acid to a reactor where water is continuously removed. The presence of a small amount of acetic acid limits the degree of polymerization to the desired level ... 

In whole cell bioprocesses, extracellular products are preferable because this removes the requirement for cell disruption and tins reduces the level of impurities in the product solution. Nevertheless, product isolation and purification can be prohibitively expensive particularly for low concentration product streams, which is a feature of many bioprocesses. 

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