Bromine index

Two methods are used to determine bromine index of aromatic hydrocarbons which contain trace amounts of olefins and are substantially free of materials lighter than isobutane and have distillation end-point lower than 288 C. The meteods measure trace amounts of unsaturations in materials which have a bromine index below 500. 

The bromine index can be measured by electrometric and coulomelric titration. In the electrometric titration method, a sample is titrated with bromide-bromate solution (0.1 N solution of mixture of potassium bromide and potassium bromate) until the end-point increase in potential remains steady for 30 s. In coulometric titration, a potassium bromide solution is used to titrate the solvent until the bromine concentration increases because it is no longer being consumed by the unsaturation of the solvent.  

Bote methods can be used for setting specification, quality control, and testing of development solvents to find olefinic content. The methods do not differentiate between the types of unsaturations. 

The heat of eombustion of liquid hydrocarbon fuels ean be determined with bomb calorimeter. Two definitions are used in result reporting gross heat of combustion (the quantity of energy released from fuel burned in constant volume with all products gaseous 

Gross calorific value and ash content of waste materials can be determined by a calorimetric method. After a calorimetric analysis, the bomb washing can be used to determine of mineral content by elemental analysis. The sample is burned under controlled conditions in oxygen. The calorimeter is standardized by burning known amount of benzoic acid. The formation of acids can additionally be determined by titration. 

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The tendency for a solvent to form deposits by polymerization of impurities such as olefins is measured by the test for potential gums . Olefin content can also be represented by the bromine index , which is a measure of the degree of unsaturation (see paragraph 3.4.1). 

Phenol quahty tests and analyses can be divided into two categories wet lab and Hquid and gas chromatography. In the wet lab, phenol is tested for pH, sohdification point, solubiUty in water, bromine index, color, and distillation ranges. Phenol concentration, impurities, and CHP contents are analy2ed using highly automated Hquid and gas chromatography. 

Bromine number (ASTM D-1159) and bromine index (ASTM D-2710) are qualitative methods to measure the reactive sites of a sample. Bromine reacts not only with olefm bonds, but also with basic nitrogen molecules and with some aromatic sulfur derivatives. Neverthele.ss. olefins are the most common reactive sites and the bromine number is used to indicate olefinicity of the feed. 

Alternatively, the bromine index is the number of milligrams of bromine that will react with 100 grams of the sample, and is most often used by the chemical industry for stocks that have very low olefin contents. 

Feedstock is typically C10 to C13 normal paraffins of 98+% purity. LAB product has a typical Bromine Index of less than 10. 

Yields 100,000 metric tons (mt) of cumene are produced from 65,000 mt of benzene and 35,300 mt of propylene giving a product yield of over 99.7%. Cumene product is at least 99.95% pure and has a Bromine Index of less than 2, without clay treatment. 

Because new high-acfivify befa zeolife cafalysfs such as QZ-2000 catalyst are such strong acids, they can be used at lower reaction temperatures than SPA catalyst or other relatively lower-activity zeolites such as MCM-22 catalyst. The lower reaction temperature in turn reduces the olefin oligomerization reaction rate, which is relatively high for SPA catalyst. The result is that beta zeolite catalysts tend to have higher selectivity to cumene and lower selectivity to both nonaromatics that distill with cumene (such as olefins, which are analyzed as Bromine Index, and saturates) and heavy by-products. For example, although butyl-benzene is typically produced from traces of butylene... 

Table 3 compares LAB product properties for the HF, AICI3, and Detal catalyst systems. Bromine index and sulfonatability are the key measures of product quality, as they affect final product value. High-bromine index LAB also will produce a more colored sulfonate. Tetralin content can be important, as it relates to the ultimate biodegradation of the product and sulfonability. 

An indication of naphtha composition may also be obtained from the determination of aniline point (ASTM D-1012, IP 2), freezing point (ASTM D-852, ASTM D-1015, ASTM D-1493) (Fig. 4.2), cloud point (ASTM D-2500) (Fig. 4.3), and solidification point (ASTM D-1493). And, although refinery treatment should ensure no alkalinity and acidity (ASTM D-847, ASTM D-1093, ASTM D-1613, ASTM D-2896, IP 1) and no olefins present, the relevant tests using bromine number (ASTM D-875, ASTM D-1159, IP 130), bromine index (ASTM D-2710), and flame ionization absorption (ASTM D-1319, IP 156) are necessary to ensure low levels (at the maximum) of hydrogen sulfide (ASTM D-853) as well as the sulfur compounds in general (ASTM D-130, ASTM D-849, ASTM D-1266, ASTM D-2324, ASTM D-3120, ASTM D-4045, ASTM D-6212, IP 107, IP 154) and especially corrosive sulfur compounds such as are determined by the Doctor test method (ASTM D-4952, IP 30). 

When classes of hydrocarbons, such as olefins, need to be measured, techniques such as bromine index are used (ASTM D-1492, ASTM D-5776). 

NMR spectra show a massive peak at 8 = 4.8 ppm, characteristic of structure P9d. At 8 = 5.2 ppm, a slight signal indicates structure P9d. The P9b unit can become partially cyclized to give structure PSe- When the polymer is prepared at low temperature, its bromine index is about 54%, which corresponds to a monocyclized structure P9e. As the polymerization temperature increases, the intensity of the characteristic sig-... 

C. Pasquini, E.V. Aquino, M.V. Rebougas, F.B. Gonzaga, Robust flow-batch coulo-metric/biamperometric titration system Determination of bromine index and bromine number of petrochemicals, Anal. Chim. Acta 600 (2007) 84. 

Description Olgone is an alternative solution to clay treating that is used to reduce olefins content and thus, lower the Bromine Index (Bl) of heavy reformate and aromatic extract streams. In this process, a stream of either mixed xylenes, benzene/toluene or a combination of each is preheated in a feed heater (1). The stream is then sent to a liquid-phase reactor (2) containing the ExxonMobil proprietary EM-1800 catalyst. Similar to a clay treater system, a typical Olgone treater system consists of two vessels with one in service and one in standby mode (3). 

ASTM D 5776-98. Standard method for bromine index of aromatic hydrocarbons by electrometric titration. 

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