Solution organic

EPW etch solutions can be affected by many operational factors such as bath design, contamination levels, silicon content in the solution, and oxygen pressure.  

FIGURE 7.22. Etch rate ([l/h ) of (100) silicon in ternary mixtures of hydrazine, water, and iso-2-propyl alcohol at their boiling point at atmospheric pressure, ox, silicon surface oxidized by the mixture and not etched st, silicon surface stained by the mixture and not etched. (Reprinted with permission from Lee. 1969, American Institute of Physics.) 

FIGURE 7.23. Etch rate of silicon as a function of the water content of the etch with pyrocatechol content held constant (0.03 M). After Finne and Klein. (Reproduced by permission of The Electrochemical Society, Inc.) 

The effect of potential is shown in Fig. 7.25 the etch stops at the passivation potential and decreases with cathodic polarization for both n-Si and p-Si. The etch rate dependence on potential is rather different from that in KOH, where the p-Si etch rate varies only slightly with cathodic polarization (Fig. 7.15). Also, the etch rates at 

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Jorgensen W L, J M Briggs and M L Contreras 1990. Relative Partition Coefficients for Organic Solute from Fluid Simulations. Journal of Physical Chemistry 94 1683-1986. 

The reaction was strongly exothermic. After the addition the cooling bath was removed and after 20 min the almost clear solution was poured into 500 ml of water. After shaking and separation of the layers the organic solution was washed five times with 200-ml portions of water in order to remove the HMPT (note 2). 

The combined organic solutions were washed five times with saturated sodium chloride solution and subsequently dried Over magnesium sulfate. After concentration of the extract in a water-pump vacuum the residue was distilled through... 

A solution of 0.10 mol of lithiated methoxyallene in about 70 ml of hexane and 50 ml of THF (see Chapter II, Exp. 15) was cooled to -40°C. Ory, pure acetone (0.12 mol) was added dropwise during 10 min, while keeping the temperature at about -30°. Five minutes after the addition 100 ml of saturated NHi,Cl solution, to which 5 ml of aqueous ammonia had been added (note 1), were run in with vigorous stirring. The product was extracted three times with diethyl ether. The combined organic solutions were dried over potassium carbonate and subsequently... 

R = tert.-CijHg). The combined organic solutions were dried over magnesium sulfate... 

The mixture was then poured into a solution of 10 g of KCN or NaCN and 40 g of NHi,Cl in 400 ml of water. After vigorous shaking the layers were separated and the aqueous phase was extracted four times with diethyl ether. The combined organic solutions were dried over MgSOi, and concentrated in a water-pump vacuum. 

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. 

Pt(CO)2Cl2] is used to deposit thin films of metallic platinum on surfaces. Concentiated organic solutions of poorly defined platinum complexes of alkyl mercaptides or sulforesinates are used to coat ceramics and glass. 

The aromatic ring of alkylphenols imparts an acidic character to the hydroxyl group the piC of unhindered alkylphenols is 10—11 (2). Alkylphenols unsubstituted in the ortho position dissolve in aqueous caustic. As the carbon number of the alkyl chain increases, the solubihty of the alkah phenolate salt in water decreases, but aqueous caustic extractions of alkylphenols from an organic solution can be accomphshed at elevated temperatures. Bulky ortho substituents reduce the solubihty of the alkah phenolate in water. The term cryptophenol has been used to describe this phenomenon. A 35% solution of potassium hydroxide in methanol (Qaisen s alkah) dissolves such hindered phenols (3). 

Equation 7 shows that as AP — oo, P — 1. The principal advantage of the solution—diffusion (SD) model is that only two parameters are needed to characterize the membrane system. As a result, this model has been widely appHed to both inorganic salt and organic solute systems. However, it has been indicated (26) that the SD model is limited to membranes having low water content. Also, for many RO membranes and solutes, particularly organics, the SD model does not adequately describe water or solute flux (27). Possible causes for these deviations include imperfections in the membrane barrier layer, pore flow (convection effects), and solute—solvent—membrane interactions. 

When it was recognized (31) that the SD model does not explain the negative solute rejections found for some organics, the extended solution—diffusion model was formulated. The SD model does not take into account possible pressure dependence of the solute chemical potential which, although negligible for inorganic salt solutions, can be important for organic solutes (28,29). 

The solubihty of hydrophobic substances in, or their absorbabiUty on suspended particles, on sediments, on biota, or on soil particles can be related to the solubihty of these substances in organic solvents. The solvent -octanol, CH2(CH2)yOH, is a kind of surrogate for many kinds of environmental and physiological organic substances and has become a reference phase for organic phase water partitioning of organic solutes. 

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