Bromine abundance

Huang L, Sturchio NC, Abrajano T, Heraty LJ, Holt BD (1999) Carbon and chlorine isotope fractionation of chlorinated aliphatic hydrocarbons by evaporation. Org Geochem 30(8A) 777-785 Jambon A, Deruelle B, Dreibus G, Pineau F (1995) Chlorine and bromine abundance in MORB the contrasting behavior of the Mid-Atlantic Ridge and East Pacific Rise and implications for chlorine geodynamic cycle. Chem Geol 126 101-117... 

Compounds that contain chlorine, bromine, sulfur, or silicon are usually apparent from prominent peaks at masses 2, 4, 6, and so on, units larger than the nominal mass of the parent or fragment ion. Eor example, when one chlorine atom is present, the P + 2 mass peak will be about one-third the intensity of the parent peak. When one bromine atom is present, the P + 2 mass peak will be about the same intensity as the parent peak. The abundance of heavy isotopes is treated in terms of the binomial expansion (a -I- h) , where a is the relative abundance of the light isotope, b is the relative abundance of the heavy isotope, and m is the number of atoms of the particular element present in the molecule. If two bromine atoms are present, the binomial expansion is... 

For other elements that occur with major relative abundances of more than one isotope in the natural state, the isotope pattern becomes much more complex. For example, with chlorine and bromine, the presence of these elements is clearly apparent from the isotopes Cl and for chlorine and Br and Br for bromine. Figure 47.2a shows the molecular ion region for the compound chlorodecane. Now, there are new situations in that C, C, C1, and Cl isotopes all have probabilities of occurring together. Thus, there are molecular ion peaks for + Cl, C + Cl, + Cl, and so on. Even so, the isotopic ratio of 3 1 for Cl to Cl is very clear... 

Magnesium sulfate heptahydrate may be prepared by neutralization of sulfuric acid with magnesium carbonate or oxide, or it can be obtained directly from natural sources. It occurs abundantly as a double salt and can also be obtained from the magnesium salts that occur in brines used for the extraction of bromine (qv). The brine is treated with calcium hydroxide to precipitate magnesium hydroxide. Sulfur dioxide and air are passed through the suspension to yield magnesium sulfate (see Chemicals frombrine). Magnesium sulfate is a saline cathartic. 

Bromine is widely distributed ia nature but ia relatively small amounts. Its abundance ia igneous rock is 0.00016% by weight and ia seawater is 0.0065% by weight. The only natural minerals that contain bromine are some silver haUdes, including bromyrite [14358-95-3] embolite [1301-83-3], Ag(Cl,Br),... 

Bromine is substantially less abundant in crustal rocks than either fluorine or chlorine at 2.5 ppm it is forty-sixth in order of abundance being similar to Hf 2.8, Cs 2.6, U 2.3, Eu 2.1 and Sn 2.1 ppm. Like chlorine, the largest natural source of bromine is the oceans, which contain 6.5 x 10 %, i.e. 65 ppm or 65mg/l. The mass ratio Cl Br is 300 1 in the oceans, corresponding to an atomic ratio... 

Bromine is a red-orange liquid with an average atomic mass of 79.90 amu. Its name is derived from the Greek word bromos (fipofios), which means stench. It has two naturally occurring isotopes Br-79 (78.92 amu) and Br-81 (80.92 amu). What is the abundance of the heavier isotope ... 

Look for characteristic isotopic abundances that show the presence of bromine, chlorine, sulfur, silicon, and so on. If the deduced molecular ion is of sufficient intensity, the probable molecular formula may be determined using the observed isotopic abundances of the molecular ion region. Set the deduced molecular ion, M, at 100% abundance, and then calculate the relative abundances of M + 1 and M + 2 either manually or using the data system. 

The presence of chlorine and/or bromine is easily detected by their characteristic isotopic patterns (see Appendix 11). As in many aliphatic compounds, the abundance of the molecular ion decreases as the size of the R group increases. For example, in the El mass spectra of methyl chloride and ethyl chloride, the molecular ion intensities are high, whereas in compounds with larger R groups such as butyl chloride, the molecular ion peak is relatively small or nonexistent. 

E.35 A mass spectrum of Br2 has three peaks, with the mass numbers 158, 160, and 162. (a) Use this information to determine which isotopes of bromine occur in nature, (b) If the relative heights of the peaks, which depend on abundance, are 33.8, 33.3. and 32.9. respectively, which isotope is more abundant ... 

Of major concern are the health and environmental impacts of the abundant chlorinated and brominated hydrocarbons (ref. 2). These materials have numerous industrial applications as pesticides, solvents, propellants, refrigerants, plastics, fire retardants and extinguishers, disinfectants for drinking water, pharmaceuticals and electronic chemicals. Many chemical manufacturers utilize chlorinated and brominated organics as intermediates. It is estimated, for instance, that almost 85 % of the pharmaceuticals produced in the world require chlorine at some stage of synthesis. 

During incineration of 1 in the polymeric matrix debromination/hydrogenation occur in addition to cyclization process. Tetrabrominated dibenzofuran isomers are the most abundant products formed in the temperature range between 300° or 400° (Figure 6 shows Br-composition at 300° - 800°C). Incineration at 400°C gives tetrabromo-benzofurans in yields up to 13 % (Fig. 6). Besides of PBDF, brominated dibenzodioxins are also formed, but to a much lesser extent (30-90 ppm) (ref. 11). 

Aromatic bromine compounds can be formed and transformed during various thermal processes, like aromatic chlorine compounds (ref. 22). Brominated dibenzodioxins and -furans and mixed brominated/chlorinated compounds have been detected in trace levels in the fly ash of a municipal waste incinerator (ref. 23).Chlorine is generally abundant compared to the bromine of typical municipal waste the chlorine vs. bromine ratio is in the range of 250 1. 

Bodner and Domin (2000) demonstrated the inability of many university students to interpret abbreviated structural portrayals with some atoms implied, rather than shown. The students were asked to predict the major products of the reaction of bromine with methylcyclopentane portrayed as in Fig. 1.2, and to estimate the ratio of the products if bromine radicals were just as likely to attack one hydrogen atom as another. Most of the 200 students predicted three products, with a relative abundance 3 2 2 (Fig. 1.4). 

Hypobromous acid so produced from the naturally occurring bromide in the ocean is rapidly consumed upon demand and is nontoxic to the plant. This natural process helps explain why seaweeds in the ocean are not overcome by adherent microbial biomass and macrofoulants that, for example, rapidly foul the surfaces of ships and piers in the sea. Although chloride is far more abundant than bromide, certain seaweeds preferentially make hypobromous acid in situ. The brominating activity of Laminaria digitata is shown by demonstration (Figure 3) in a replication of the work by Wever, et al.2. 

Regarding the degradation of penta-BDE mixture components, Table 5 shows that there was a significant removal percentage for all components detected. BDE-183, which corresponds to the highest brominated component and the less abundant... 

There are many natural sources of chlorine compounds, which is not surprising considering that it is the 20th most abundant element. Salt and salt water are widely available the Great Salt Lake contains 23% salt, and the Dead Sea contains about 30%. Because salt is so abundant, most minerals that contain chlorine are not important sources for economic reasons. Bromine is found in some salt brines and in the sea, as are some iodine compounds. 

Fujita et al. [18] studied formation of halogenated (chlorinated and brominated) NPEOs and NPECs during wastewater treatment. Halogenated derivatives were found to be produced during the disinfection processes by chlorination accounting for up to 10% of total nonylphenolic compounds. They were found in 25 of 40 WWTPs with concentrations up to 6.5 xgL 1 in secondary effluent and 52.4 jig L-1 in final effluent. Of all halogenated compounds, BrNPECs (nEo = 1-2) were found to be the most abundant. 

If there are two bromine or four chlorine atoms contained in the empirical formula, the isotopic peaks become more intensive than the monoisotopic peak, because the second isotope is of much higher abundance than in case of the isotope. 

In the other study. X-ray fluorescence spectroscopy was used to analyze trace element concentrations by observing dusts on 37 ram diameter cellulose acetate filters (20). Twenty-three elutriator and twenty-three area samples from 10 different bales of cotton were analyzed. The average fraction of total dust accounted for by the elements analyzed was 14.4% amd 7.6% for vertical elutriator and area samples, respectively. Although the variation in absolute quantity of atn element was high, the relative abundance of an element was consistent for measurements within a bale. Averaged over all the samples analyzed, calcium was the most abundant element detected (3.6%), followed by silicon (2.9%), potassium (2.7%), iron (1.1%), aluminum (1.1%), sulfur (1.0%), chlorine (0.8%) and phosphorous (0.6%). Other elements detected in smaller aunounts included titanium, manganese, nickel, copper, zinc, bromine, rubidium, strontium, barium, mercury amd lead. 

The mass spectrometric behavior (the types and abundance ratios of the fragments) shows variations from compound to compound depending on the changes of both the metal and halogen atoms. Substitution of aluminium by gallium or that of chlorine by bromine considerably decreases the stability of the molecular ion. 

ISOTOPES There are a total of 40 isotopes of bromine. Of these, only two are stable Br-79 constitutes 50.69% of the stable bromine found on Earth, and Br-81 makes up 49.31% of the naturally occurring abundance. All the other isotopes of bromine are radioactive with half-lives ranging from 1.2 nanoseconds to 16.2 hours. 

Bromine is the 62nd most abundant element found on Earth. Although it is not found uncombined in nature, it is widely distributed over the Earth in low concentrations. It is found in seawater at a concentration of 65 ppm. This concentration is too low for the bromine to be extracted directly, so the salt water must be concentrated, along with chlorine and other salts, by solar evaporation, distillation, or both. 

Table 1.1 Isotopic abundance of common elements. Interesting to note is that chlorine and bromine have t /o naturally intense isotopes.

Two UV filters (used to block UV-rays in sunscreens and other products), octyl-p-methoxycinnamate and octyl-dimethyl-p-aminobenzoate, reacted with chlorine, producing chlorine-substituted compounds as intermediates that finally cleaved to smaller ester products [121]. Some of the identified octyl-p-methoxycinnamate DBPs showed weak mutagenic properties. Chlorinated and brominated intermediates were formed during chlorination of 2-ethylhexyl-4-(dimethylamine)benzoate and 2-hydroxy-4-methoxybenzophenone, with trichloromethoxyphenol the most abundant DBP [122]. 

For the HX additions above, we noted that, in aqueous solution, water would be the most abundant nucleophile, and the predominant product would thus be an alcohol derivative. A similar situation holds if we use aqueous bromine or chlorine, for example. The product is going to be a halo... 

Isotope ratios. For some elements (most notably bromine and chlorine), there exists more than one isotope of high natural abundance e.g. bromine has two abundant isotopes - Br 49 % and Br 51 % chlorine also has two abundant isotopes- Cl 25 % and Cl 75% (Table 4.1). The presenee of Br or Cl or other elements that contain significant proportions (> 1%) of minor isotopes is often obvious simply by inspection of ions near the molecular ion. 

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