Bromine, reactivity

Table 8. Brominated Reactive Flame Retardants and Intermediates...

The free-radical reaction of propane with bromine. This 97 3 ratio of products shows that bromine abstracts a secondary hydrogen 97 times as rapidly as a primary hydrogen. Bromination (reactivity ratio 97 1) is much more selective than chlorination (reactivity ratio 4.5 1). 

Another way to use pyridine in brominations is to make a stable crystalline compound to replace the dangerous liquid bromine. This compound, known by names such as pyridinium tribromide, is simply a salt of pyridine with the anion Brj. It can be used to brominate reactive compounds such as alkenes (Chapter 20). 

The second problem is the relationship between the position of the substituent in the pyrazole nucleus and its mobility. In the 1-phenylpyrazole series in their reactions with Grignard reagents, the bromine reactivity decreases in the order 5-Br>4-Br>3-Br (B-76MI40402). When an electron-withdrawing group is present at the 4-position, the 5-chloropyrazole is more reactive than 3-chloropyrazole, but this has been attributed to bond fixation (Section 4.02.3.9). Thus, this problem needs further clarification. 

Chlorine Chemistry in ODEs and Br-Cl Interactions MARINE BOUNDARY LAYER. 4.1 Sea Salt Aerosols Reactive Chlorine Reactive Bromine Reactive Iodine Surface Segregation Effects IMPACT OF HALOGEN CHEMISTRY ON SPECIES OTHER THAN OZONE. 5.1 Alkanes. 5.2 Mercury. 5.3 Sulfur SALT LAKES... 

In bromination cyclopropylalkenes are extremely reactive, and c-PrCH=CH2 was estimated to be at least 10 times more reactive than n-BuCH=CH2 An analysis of the bromination reactivity of a large number of alkenes led to the conclusion that while most reacted through bridged bromonium ions that c-PrCH=CH2 proceeded through an open ion . ... 

The bromine number is the number of grams of bromine that will react with 100 g of the sample under the test conditions. The magnitude of bromine number is an indication of the quantity of bromine-reactive constituents and is not an identification of constituents. It is used as a measure of aliphatic unsaturation in petroleum samples and percentage of olefins in petroleum distillates boiling up to approximately 315°C (600°F). In the test, a known weight of the sample dissolved in a specified solvent maintained at 0-5°C (32-41 °F) is titrated with standard bromide-bromate solution. Determination of the end point is method dependent. 

Brominated Reactive Tfetrabromobisphenol A (TBA) Brominated polyols Tfetrabromophthalic anhydride Additive Decabromodiphenyl oxide (DBDPO) TBA derivatives Hexabromocyclodecane/do decane Hexabromodiphenoxyethane Brominated polystyrene... 

The magnitude of the bromine number is an indication of the quantity of bromine-reactive constituents, not an identification of constituents therefore, its application as a measure of olefinic unsaturation should not be undertaken without the study given in Annex Al. 

For petroleum hydrocarbon mixtures of bromine number less than 1.0, a more precise measure for bromine-reactive constituents can be ol ned by using Test Method D 2710. If the bromine number is less than O.S, then Test Method D 2710 or the comparable bromine index methods for industrial aromatic hydrocarbons. Test Method D 1492, must be used in accordance with their respective scopes. The practice of using a factor of 1000 to convert bromine number... 

This test method covers the determination of the amount of bromine-reactive material in aromatic hydrocarbons. It is usually applied to materials having bromine indexes below 500. 

Note 1—Other test methods for determining bromine-reactive material are Test Methods D 1159, D 1491, D 2710, and D 5776. 

---