Yield and pressure

The PIIS has been calculated as a total score, which is the sum of a chemical score and a process score (Table 1). The chemical score consists of inventory, flammability, explosiveness and toxicity. The process score includes temperature, pressure and yield. Some of the scores are based on similar tables in the Dow and Mond Indices. Others have been constructed by dividing the domain of values of a parameter into ranges and assigning a score to each range. They are supposed to be modified in the future. 

Prototype Index of Inherent Safety (PUS) Chemical score inventory, flammability, explosiveness and toxicity Process score temperature, pressure and yield Total score sum of the chemical and process scores... 

A phosphorus ylide serves as the carbanionic component in a synthesis of pyran-2-ones from 1,3-diketones (70ACS343). A Wittig reaction between the ylide and one of the carbonyl groups is envisaged as the first step in the sequence and the resulting keto ester spontaneously cyclizes. The reaction is conducted under pressure and yields are low. 

It encompasses work published up to early 1990.150 different pyrolysis reactions are classified — a detailed discussion of each work is not intended. Instead — if reported in the original pubUcation — the temperature of pyrolysis, pressure, and yield of the reactions are listed in the reaction equations. For some interesting cases by-products that have been characterized are listed as well. By this treatment the scope of the sulfone pyrolysis becomes obvious. 

Properties of [(FXe0)2S(0)F]+[AsF6]— Hie Raman spectrum of the colorless solid is represented in Table VII. It is remarkably similar to that of [Xe2F3]+[AsF ]". The solid is sublimable, at -- 20 , in vacuo, and the Raman spectrum of the sublimate shows only traces of [Xe2F3]+[AsFc)The solid decomposes above 64 at ordinary pressures and yields S2O6F2, Xe, and Xe2F3+AsF6 in accord with the equation... 

Alkynylsilanes will react with tributyltin oxide in an analogous fashion if tetrabutyl-ammonium fluoride is used as a catalyst.96 The hexamethyldisiloxane which is formed can readily be removed under reduced pressure, and yields are excellent (equation 8-50). 

Ketone lc (897 mg, 4 mmol) and /V-bromosuccinimidc (NBS, 712 mg, 4 mmol) were triturated together in a porcelain mortar for 5 min and after 1 h water (4 mL) was added and the mixture converted into a paste. After filtration and additional washing with water, the crude product was dried overnight in a desiccator under reduced pressure and yielded 1.187 g (98%) of pure product 2 c. 

Most substances can assume the three forms solid, liquid, and vapour, and we may inquire rmder what conditions the three can coexist. For any given pair of phases at a selected pressure there is in general a definite equilibrium temperature (with an exception which will be referred to later). For solid and liquid the equilibrium temperature may be plotted as a function of pressure, and yields a definite curve. For liquid and vapour there is a corresponding curve, neither identical with nor parallel to that for solid and liquid. The two lines will in general, therefore, cut at a definite point, representing a fixed temperature and a fixed pressure. Under these conditions the three phases can coexist stably. They can do so nowhere else. The point of coexistence is called the triple point. 

The prototype index of inherent safety (PUS) (developed by Edwards and Lawrence, 1993) is a numerical score based on the nature of chemicals used and the type of process. The PUS was developed to compare processes based on raw materials and the sequence of reaction steps only. This method does not consider the other parts of the process. PUS is calculated as a total score and consists of two parts the chemical score and the process score. The first one is made up of inventory, flammability, explosiveness, and toxicity. The second one is made up of temperature, pressure, and yield. 

Table 3 provides the values for pressure and yield according to the pump type and strokes. 

Trichloroethylene is not attacked by dilute acids or alkalis, but when heated with sodium hydroxide under pressure it yields sodium gly-collate. In the presence of light and oxygen dichloroethanoyl chloride is formed, which can react with any moisture present to give small amounts of highly corrosive HCl. Numerous stabilizers have been patented. 

For a single stage separator i.e. only one separator vessel, there is an optimum pressure which yields the maximum amount of oil and minimises the carry over of heavy components into the gas phase (a phenomenon called stripping). By adding additional separators to the process line the yield of oil can be increased, but with each additional separator the incremental oil yield will decrease. 

The field-density concept is especially usefiil in recognizing the parallelism of path in different physical situations. The criterion is the number of densities held constant the number of fields is irrelevant. A path to the critical point that holds only fields constant produces a strong divergence a path with one density held constant yields a weak divergence a path with two or more densities held constant is nondivergent. Thus the compressibility Kj,oi a one-component fluid shows a strong divergence, while Cj in the one-component fluid is comparable to (constant pressure and composition) in the two-component fluid and shows a weak... 

A drop of a dilute solution (1%) of an amphiphile in a solvent is typically placed on tlie water surface. The solvent evaporates, leaving behind a monolayer of molecules, which can be described as a two-dimensional gas, due to tlie large separation between tlie molecules (figure C2.4.3). The movable barrier pushes tlie molecules at tlie surface closer together, while pressure and area per molecule are recorded. The pressure-area isotlienn yields infonnation about tlie stability of monolayers at tlie water surface, a possible reorientation of tlie molecules in tlie two-dimensional system, phase transitions and changes in tlie confonnation. Wliile being pushed togetlier, tlie layer at... 

Place 100 g. of adipic acid in a 750 ml. round-bottomed flask and add successively 100 g. (127 ml.) of absolute ethyl alcohol, 250 ml. of sodium-dried benzene and 40 g. (22 ml.) of concentrated sulphuric acid (the last-named cautiously and with gentle swirling of the contents of the flask). Attach a reflux condenser and reflux the mixture gently for 5-6 hours. Pour the reaction mixture into excess of water (2-3 volumes), separate the benzene layer (1), wash it with saturated sodium bicarbonate solution until eflfervescence ceases, then with water, and dry with anhydrous magnesium or calcium sulphate. Remove most of the benzene by distillation under normal pressure until the temperature rises to 100° using the apparatus of Fig. II, 13, 4 but substituting a 250 ml. Claisen flask for the distilling flask then distil under reduced pressure and collect the ethyl adipate at 134-135°/17 mm. The yield is 130 g. 

Diethyl oxalate. Reflux a mixture of 45 g. of anhydrous oxalic acid (1), 81 g. (102-5 ml.) of absolute ethyl alcohol, 190 ml. of sodium-dried benzene and 30 g. (16-5 ml.) of concentrated sulphuric acid for 24 hours. Work up as for Diethyl Adipate and extract the aqueous laj er with ether distil under atmospheric pressure. The yield of ethyl oxalate, b.p. 182-183°, is 57 g. 

Into a 500 nil. round-bottomed flask, provided with a double surface condenser, place 50 g. (63 ml.) of pure, dry acetone, 50 g. (47 ml.) of ethyl cyanoacetate (Section 111,131) and 0 -5 g. of piperidine. Allow to stand for 60 hours and heat on a water bath for 2 hours. Treat the cold reaction mixture with 100 ml. of ether, wash with dilute hydrochloric acid, then with water, and dry over anhydrous sodium or magnesium sulphate. Distil under diminished pressure and collect the ethyl fsopropylidene cyanoacetate (ethyl a-cyano-pp-dimethylacrylate) at 114-116°/14mm.(l). The yield is 39 g. 

Transfer the reaction mixture to a Claisen flask and distil vmder atmospheric pressure imtil the temperature reaches 135-140° (3). Distil the residue under diminished pressure and coUeot the benzyl chloride at 64—69°/12 mm. The latter upon redistillation boils largely at 63- 65°/12 mm. The yield of benzyl chloride is about 100 g. 

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