Bromoform table

The present method utilizes dichlorocarbene generated by the phase-transfer method of Makosza4 and Starks.5 The submitters have routinely realized yields of pure distilled isocyanides in excess of 40%.6 With less sterically hindered primary amines a 1 1 ratio of amine to chloroform gives satisfactory results. Furthermore, by modifying the procedure, methyl and ethyl isocyanides may be prepared directly from the corresponding aqueous amine solutions and bromoform.7 These results are summarized in Table I. 

DNAPLs have higher densities than water, most between 1 and 2 g/mL, some are near 3 g/mL, for example, bromoform, which has a density of 2.89 g/mL. They have limited water solubilities, and are usually found as the free-phase immiscible with water or as residuals trapped by soil. Most DNAPLs are volatile or semivolatile Pankow82 has listed information on their physical and chemical properties, such as molecular weight, density, boiling points, solubility in water, vapor pressure, sediment/water partition coefficient, viscosity, Henry s law constant, and so on (see Tables 18.8 and 18.9). 

With the exception of the parent compounds, where the Michael adducts are isolated, acrylic esters [see, e.g. 6,7,31,105,111 ] and nitriles [6,7], and vinyl ketones [26, 113, 115] generally yield the cyclopropanes (Table 7.6) under the standard Makosza conditions with chloroform. Mesityl oxide produces a trichlorocyclopropy-lpropyne in low yield (10%) [7]. When there is no substituent, other than the electron-withdrawing group at the a-position of the alkene, further reaction occurs with the trichloromethyl anion to produce spiro systems (35-48%) (Scheme 7.12) [7, 31]. Under analogous conditions, similar spiro systems are formed with a,p-unsaturated steroidal ketones [39]. Generally, bromoform produces cyclo adducts with all alkenes. Vinyl sulphones are converted into the dichlorocyclopropane derivatives either directly or via the base-catalysed cyclization of intermediate trichloromethyl deriva-... 

Analogous reactions with bromoform produces the corresponding 3-bromo derivatives [6], while the reaction of alkylindoles with chlorofluorocarbene produces a complex mixture of halogenated heterocycles (Table 7.18) [9]. 

Pecher et al. (2002) show how the uptake of ferrous iron from aqueous solution, by iron oxides, leads to the formation of a variety of reactive surface species that are capable of reducing polyhalogenated methanes (PHMs). The iron oxides used in the experiments and their characteristics are shown in Table 16.2. The PHMs studied include bromodichloromethane (CHBrCl ), chlorodibromomethane (CHBr Cl), bromoform (CHBr ), tetrachloromethane (CCl ), hexachloroethane (HCE), fluorotribromomethane (CFBrj), bromotrichloromethane (CBrCl ) and dibromodichloromethane (CBr Cy. 

Flame Studies. The effects of ethylene dibromide, bromoform, and chloroform on flame speeds of several hydrocarbons were examined. These studies were carried out with 5% molar concentration of the halogen compounds in each hydrocarbon. All the experiments were carried out under identical conditions, and the results reported in Table I are the mean of at least three separate determinations. 

In particular, Table 2.1 shows for atactic polystyrenes (in ref. 68 also isotactic polystyrene has been investigated, yielding C = —10300 Br in bromoform) that the influence of molecular weight (measurements in bromo-benzene and on the bulk polymer) is negligible or rather small. 

Krivchenko et al (Ref 50) studied the deton parameters of RDX mixed with a variety of liqs of different densities (ranging from acet at 0.79g/cc to bromoform at 2.81g/cc). Their results are summarized in Table 1 We see from Table 1 that the deton parameters for the filled systems are higher than those for RDX charges (of 0.3 to 0.5mm grains) at 1.03g/cc, approaching and sometimes exceeding the values of one or all of the deton parameters of pure RDX at pQ = 1.44g/cc (this d is approx equal to the avg d of the system). It should be noted that there is a sharp increase in the press of the Filled system because of the simultaneous increases in the deton vel, the mass vel, and the avg charge d... 

Consequently, for the haloform case (Table 4.10), since repulsion for chlorine is less than that for fluorine, chlorine as a substituent facilitates carbanion formation much more than fluorine. The enhanced acidities of bromoform and iodoform have been attributed to the release of steric strain on deprotonation, while the increased availability of [Pg.110]

Aldehydes may be converted to ( )-alkenyl halides by the reaction of CrCh with a haloform in THF. The highest overall yields for the conversion were with iodoform, but somewhat higher (E) (Z) ratios were observed with bromoform or chloroform. Other low-valent metals, such as tin, zinc, manganese and vanadium, were ineffective. As the examples in Table 19 indicate, the reaction is selective for the ( )-isomer, except in the case of an a,3-unsaturated aldehyde. In addition, the reaction with ketones is sufficiently slow for chemoselectivity to be observed for mixed substrates. 

Bromomethanes at single locations in the South Atlantic normally show lower concentrations than or similar to those measured for the Southern Ocean. For example, Class and Ballschmiter determined the bromoform and dibromomethane concentration at 6° S, 6° W to be 0.8 and 0.3 ng F (3), whereas Abrahamson and Klick measured higher contents of 4.5 and 1.3 ng l at 52° S, 6°W (55), respectively. The latter authors also reported low concentrations of iodochloromethane and iodopropane in the range of 0.07-0.13 ng 1 in an Antarctic sea water sample. That diiodomethane is the dominant iodinated compound in coastal waters, especially during spring, was found by Klick on the Swedish coast (56). This confirms the results listed in Table 7.1 for Arctic coastal water. 

The measured concentrations of VHOCs in surface sea water and in the corresponding air can be used with equation (1) to calculate the flux, and therefore the yearly input, of these substances from the ocean into the atmosphere. Corresponding results for the Southern Ocean and the Arctic Ocean in comparison with the total global input from all oceans into the atmosphere are summarized in Table 7.6 for iodomethane and bromoform. Different assumptions, e.g., the use of representative analytical data or a similar production rate in all oceans, make the calculated transfer into the atmosphere very uncertain. However, the data in Table 7.6 suggest that about 5-10% of the global atmospheric input of iodomethane and probably more than 10% of the bromoform input comes from the Southern... 

Table 7.6. Transfer of biogenic iodomethane and bromoform from the polar oceans into the atmosphere and comparison with the global input...

Alternatively, dibromoiodomethane may be used instead of bromoform. An experimental procedure for the synthesis of 9-bromobicyclo[6.1.0]nonane by reaction of bromoform, diethylzinc and cyclooctene is described in Houben-Weyl, Vol. El 9 b, pp 1605-1606. Some products prepared by this method are collected in Table 2. 

Table 2. Bromocyclopropanes from Bromoform, Diethylzinc and Alkenes in the Presence...

Of the many catalysts which were investigated, benzo-15-crown-5 and tetramethylam-monium chloride favor cyclopropanation (1), though in the latter case long reaction times are required to reach satisfactory yields, while tetraphenylarsonium chloride promotes alkylation (2) . Evidently, the optimum conditions for cyclopropanation of any particular allylic bromide must be determined in each case, e.g. allyl bromide and bromoform (1 1.1) with ben-zyltriethylammonium chloride as catalyst gave l,l-dibromo-2-bromomethylcyclopropane as the main product 3-bromocyclohexene afforded a 1,1-dibromocyclopropane derivative in a high yield, in the presence of all catalysts listed in Table 28 except for tetraphenylarsonium chloride. On the other hand, if type 1 and 3 products only are formed, they may easily be separated by distillation. 

Examples of toxic compounds, including some important intermediates and starting materials in the chemical industry, are shown in Figure 3.3. Many alkali fluorides, such as alkali hexafluorosilicate, alkali hydrogen difluoride, or alkali sulfuryl fluoride, are well known toxic substances. Sulfur dioxide and ammonia (ubiquitous gases) are toxic, as are chlorine, metallic mercury vapors, many organic phenol compounds, amino aromatic compounds such as aniline, and many substituted amino-benzene derivatives. Additionally, many diisocyanates are toxic, e.g., 2,4- and 2,6-toluene diisocyanate (TDI), hexamethylene diisocyanate (HDI), chloro-, bromo-, and iodoacetic acid, methyl bromide, tribromomethane (bromoform), carbon tetrachloride, and formaldehyde. Also, many natural compounds present in many plants have toxic properties, and a selection of these are listed in Table 3.4. 

The reproducibility (six replicates) of MIMS responses was compared to that obtained by the reference method. The results (expressed as standard deviation percentage, SD%, Table 16.1) were comparable for the two methods, with the exception of carbon tetrachloride and bromoform, whose MIMS standard deviations were greater than those obtained by P T/GC/MS. The standard deviation percentage for compounds of relatively high polarity and/or low volatility (such as toluene, ethylbenzene, cumene, bromoform, and carbon tetrachloride) was relatively higher than that obtained by P T/GC/MS these results probably indicate an unfavorable partitioning equilibrium for these particular compounds in the membrane. 

The isolated aliphatic C-H group has been studied in halogenated compounds. Table 2.5 lists the band assignments for chloroform and bromoform, expressed in terms of normal modes. The authors mention that some of these bands are split by the nondegeneracy of the deformation vibrations. These assignments are in agreement with those of Kaye. ... 

As shown in Table 1.5 for PBX-9502 and Table 1.6 for Composition B, the measured reaction zone parameters for heterogeneous explosives vary considerably with the experimental technique. The reported reaction zone thickness for PBX-9502 (95/5 TATB/Kel F, p = 1.894) varies by a factor of 8 between the metal free-surface measurement of Craig and the foil-water measurement reported by Sheffield As shown in Table 1.6, the reaction zone thickness of Composition B (64/36 RDX/TNT, p = 1.713) varies by a factor of 4 between the bromoform measurement and the conductivity measurement of Hayes . 

---