Mass indicators

Deliver from a pipette 10 c.c. of the oil into a glass dish (preferably a round-bottom one) of 50 c.c. capacity, which is imbedded in finely cracked ice. Add 10 c.c. of concentrated arsenic acid (containing about 85 per cent, arsenic acid), and stir until precipitation is complete. When the mixture ceases to congeal further, allow to stand ten minutes in the ice. At this point if the mixture forms a hard mass, indicating an oil rich in cineol, 5 c.c. of purified petroleum ether should be added, and the mass mixed well. Transfer immediately to a hardened filter paper by means of a pliable horn spatula, spread evenly over the surface of the paper, and lay a second hardened filter paper over the top. Outside of the hardened filters place several thicknesses of absorbent or filter paper, and transfer the whole to an ordinary letter-press, bringing to bear all the pressure... 

Parentheses around molar mass indicate the most stable isotope of a radioactive element. 

Figure 5.1 Mass indices and environmental factors E of the enantioselective reduction steps A-D (top) and synthesis sequences via A-via D (bottom) using EATOS according to Blaser etal. (Figures 10 and 8 in reference [1 0]). Auxiliaries (isolation) are solvents.

Mass indices and environmental factors (equations (5.1) and (5.2)) have been introduced in Section 5.1. For confidentiality reasons, neither chemical names nor exact quantities are specified concerning the industrial case studies. Instead, masses are expressed relatively to input amounts at the laboratory scale. The imit (kg kg ) expresses how many kilograms of substance are needed to produce one kilogram of product. Abbreviations used in captions of the figures are explained in Box 5.2. 

Figure 5.9 Mass indices and environmental factors E for the Dieckmann condensation reactions depicted in Scheme 5.5, using the software EATOS Results for laboratory (L) (f 0.2 kg) and operation (O) (f l 500 kg) scale, as well as for a literature protocol (Lit.) (scale 0.01 2 kg ) are shown.

Figure 5.11 Mass indices and environmental factors E at different process development stages for the synthesis depicted in Scheme 5.7. The parameters have been determined using the software EATOS (L) laboratory (f 0.1 kg), (P) pilot (f 400 kg), and (O) operation (f 1 000 kg) scale.

The mass-related metrics shown in Figure 5.11 indicate that the amount of a substrate (see also byproduct formation), an auxiliary material for reaction, and of a solvent have to be reduced. The detailed view of the mass indices of the pilot scale, for example, the segments Substrates and Aux (R) and the size of segments Substrates (excess) and Aux (R) of the environmental factor E, deliver the information listed in Table 5.2 108% base and 162% auxiliary (R) are used. The measure to increase base addition for recycling purposes was successful at the expense of 193% base, much auxiliary material Aux (R) was saved in operation scale (reduction from 162% to only 13%). This leads to an overall... 

Mass balancing unifies all metrics such as yield, atom economy, TON, TOF, and so on. Therefore, the application of mass indices and environmental factors presents itself as an integrating solution with moderate data demands. A fair comparison of alternative... 

In addition to the comparison of different stages of process development during scale up, the evaluation of alternative syntheses or processes using mass indices and environmental factors or LCA may reveal the lack of resource efficiency and thus call into question the current mode of operation. Decisions that were made in earlier stages of scale-up may then be revised. 

Some other useful mass indicators include ... 

Fig. 28. Ion image of photofragment (a) m/e = 91, (b) m/e = 29, from photodissociation of ra-propylbenzene at 248 nm. The delay times between the pump and probe laser pulses are 20 /is and 5 /is, respectively. The image of m/e = 30 is the mass indicator. (c) The intensity decay of the disk-like image, a dissociation rate of 4.9 x 104 s-1 was obtained, (d) The translational momentum distributions of m/e = 29 (thin solid line) and 91 (thick solid line), (e) The fragment translational energy distribution for the reaction C6H5C3H7 - C6HbCH2 +C2H5.

Fig. 3.37. Rough locations of chemically evolved and peculiar stars in the HR diagram. Full lines show the ZAMS with stellar masses indicated and evolutionary tracks for 0.8, 3 and 15 Af , the helium main sequence (0.5 to 1.5 A/ ),...

Figure 4 shows typical SEC profiles of two PS-3-PI diblock copolymers before and after the photodimerization reaction. [46] The appearance of a peak after the UV irradiation at a short retention time with a doubled molar mass indicates the formation of PS-3-PI-C-PI-3-PS copolymer chains. In contrast, the irradiation of SI 42 in THF without the self-assembly only leads to a slight increase of the molar mass. It confirms that the self-assembly helps to concentrate and expose the reactive ends of precursor diblock copolymers on the periphery of the core-shell micelles, which greatly increases the coupling efficiency of the photodimmerization reaction between two coumarin end groups. 

Fig. 3 ACE/MS of a synthetic all-D, Fmoc-DDXX library of 100 tetrapeptides using vancomycin as the receptor. (A-D) Selected ion electropherograms for the masses indicated (E) reconstructed ion electropherograms for runs without (left) and with (right) vancomycin in the electrophoresis buffer. See text for conditions and further explanations. (Reprinted with permission from Ref. 38. Copyright 1995 American Chemical Society.)...

A yellow coloration of the fused mass indicates chromium. The mass is taken up in the platinum dish with water and acetic acid then added a little at a time until the reaction is acid. In a small portion of the acetic acid solution the presence of chromium may be confirmed by means of lead acetate. The acetic add solution and any undissolved part of the mass are concentrated to a small volume in a porcelain dish over a naked flume and then taken to dryness on a water-bath. The residue is heated for some time in an air-oven at iio° and then treated with water and hydrochloric acid and filtered. The filtrate is tested for tin and copper by means of hydrogen sulphide. 

Ans. The atomic masses indicated on the Periodic Table of the Elements are averages, but they are calculated relative to the mass of 12C. The mass number for iodine s naturally occurring isotope is 127, which is a total of the number of protons and neutrons, not true masses. 

Experiments run in the air. Data in parentheses give area in mm2 under peak recalculated on 100.00-mg samples. Shoulders are denoted by "s". En and Ex denote endothermic and exothermic effects, respectively. The range of temperature in which mass indicated is lost is given in parentheses. The height of peak (X 10"2 mg) is given in parentheses. Shoulders are denoted by s. ... 

Of most polymers various types exist, which differ in molecular mass. The strongest example is PE, which is made at more than 10 different levels of M, the extremes differing by a factor of 20. But also within each type the chains may largely differ in length, namely by a factor of 100 or even 1000. Therefore every statement about a molar mass indicates an average. 

Alkaloids of Delphinium dictyocarpum N- Acetyldelectine and Demethylenedelt-amine.—Further investigations of the aerial parts of D. dictyocarpum DC. have yielded a new base (34), C26H41N08, m.pt. 116—118 °C.27 Spectral analyses (i.r., n.m.r., and mass) indicate the presence of an N-ethyl and three methoxy-groups, and an N-acetyl anthranilate ester, on a lycoctonine-type skeleton. Saponification of (34) gave anthranilic acid and a base identical with that obtained from delectine (35). Therefore, this new alkaloid was assigned the structure of N-acetyldelectine (34). 

Caucasian men between 30 and 65 years of age, with Body Mass Indices of 18-29 kg/m2. Volunteers were to be healthy, nonsmoking, and not receiving regular medication. 

Six white men aged between 45 and 65 years, with Body Mass Indices (BMI) of 19 - 29 kg/m2. 

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