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Biphenyl alkylation

The increased activity and stability combined with the shape-selective elfect of these tailored mordenites is illustrated beautifully by comparing results for biphenyl alkylation with those obtained using either a more traditional catalyst or non-modified zeolites. The results are summarized in Table 1 [15]. DHM-2X is a modified mordenite later referred to by Dow as 3-DDM after the more extensive studies described above. The Si02/Al203 molar ratio of this sample was 2600. The Zeolon 100 sample is a standard commercially available mordenite with a Si02/ AI2O3 ratio of 10. [Pg.155]

Pure (9-terphenyl can be obtained by fractional distillation. To obtain high purity m- or -terphenyl, the appropriate distillation fraction has to be further purified by recrysta11i2ing, 2one refining, or other refining techniques. Currently, litde demand exists for pure isomers, and only a mixture is routinely produced. Small amounts of acetone, ethanol, or methanol are used to promote dehydrocondensation, and as a result, minor amounts of methyl- or methylene-substituted polyphenyls accompany the biphenyl and terphenyls produced. For most purposes, the level of such products (<1%) is so small that their presence can be ignored. For appHcations requiring removal of these alkyl-polyphenyl impurities, an efficient process for their oxidative destmction has been described (38). [Pg.117]

Rehable estimates of annual production of biphenyl in the United States are difficult to obtain. The 1990 figure is probably on the order of 16 million kg/yr of which about half is derived from hydrodealkylation sources. About 10% of the biphenyl derived from HD A sources is consumed, as 93—95% grade, in textile dye carrier appHcations. The remainder is used for alkylation or upgraded to >99.9% grades for heat-transfer purposes. Essentially all of the high purity biphenyl produced by dehydrocondensation of ben2ene is used as alkylation feedstock or is utili2ed directly in heat-transfer appHcations. [Pg.117]

Biphenyl, terphenyl, and their alkyl or hydrogenated derivatives generally serve markets where price and performance, rather than composition, is the customer s primary concern. Performance standards for heat-transfer appHcations are usually set by the fluid suppHer. The biphenyl—diphenyl oxide eutectic (26.5% biphenyl, 73.5% DPO) represents a special case. This composition has become a widely recogni2ed standard vapor-phase heat-transfer medium. It is sold throughout the world under various trademarks. In the United States, Dow (Dowtherm A) and Monsanto (Therminol VP-1) are the primary suppHers. Alkylated biphenyls and partially hydrogenated terphenyls serving the dielectric and carbonless copy paper dye solvent markets likewise are sold primarily on the basis of price and performance characteristics jointly agreed on by producer and user. [Pg.117]

Biphenyl and mixed terphenyls as weU as their normally Hquid alkyl and partially hydrogenated derivatives are commonly stored in the Hquid or molten state. The products are noncorrosive mild steel equipment usually suffices for handling. [Pg.117]

Short-chain alkylated biphenyls are the principal biphenyl derivatives in commercial use. They are generally produced by Hquid-phase Friedel-Crafts alkylation of biphenyl with ethylene, propylene, or mixed butenes. A series of mixed ethylated biphenyl heat-transfer fluids (trademarked Therm S-600, 700, 800) is marketed by Nippon Steel. A mixed diethylbenzene—ethylbiphenyl heat-transfer fluid is also available from Dow (63). Monoisopropylbiphenyl [25640-78-2] largely as a mixture of meta- and para-isomers is produced by Koch Chemical Co. Monoisopropylbiphenyl (MIPB) was selected by Westinghouse (64,65) as a PCB replacement in capacitors and this is its primary appHcation today. For a time MIPB was also employed as a PCB replacement in pressure sensitive copy paper, but this outlet has since given way to other dye solvents. A similar product consisting of a mixture of j -butylbiphenyl isomers [38784-93-9] (66) is currently the favored dye solvent for pressure sensitive copy paper (67) manufactured in the United States. [Pg.119]

Domestic production figures for alkylated biphenyls are not readily available, but the volume is probably in the range of 10—14 million kg/yr with prices at approximately 1.50 per kg. [Pg.119]

So liefert die Reduktion von Anthracen in Gegenwart von Methyl- oder tert.-Butylchlo-rid Alkyl-dihydro-anthracene4 und 4-Jod-l-nitro-benzol, in Gegenwart von Benzol rcduziert, 4-Niiro-biphenyl (in CH3CN, 20% d. Th.)2. Analog verhalt sich Toluol5. [Pg.672]

On page 132, atropisomerism was possible when ortho substituents on biphenyl derivatives and certain other aromatic compounds prevented rotation about the bond. The presence of ortho-substituents can also influence the conformation of certain groups. In 88, R= alkyl, the carbonyl unit is planar with the trans C=0 - F conformer more stable when X=F. When X=CF3, the cis and trans are planar and the trans predominates. When R = alkyl there is one orthogonal conformation but there are two interconverting nonplanar conformations when R=0-alkyl. In 1,2-diacylbenzenes, the carbonyl units tend to adopt a twisted conformation to minimize steric interactions. " ... [Pg.172]

The compound in Fig. 3b exhibits two smectic phases (Sm and Sm ) in addition to nematic, whereas the compound in Fig. 3a exhibits only a nematic phase. The substitution of an alkoxy for an alkyl tail is known to shift phase transition temperatures considerably. In the cyano-biphenyls (Fig. 4), substitution of an alkoxy tail raises the melting point from 24 to 48 °C and T from 35 to 68 °C [22]. [Pg.8]

Pd-catalyzed asymmetric allylic alkylation is a typical catalytic carbon-carbon bond forming reaction [ 126 -128]. The Pd-complex of the ligand (R)-3b bearing methyl, 2-biphenyl and cyclohexyl groups as the three substituents attached to the P-chirogenic phosphorus atom was found to be in situ an efficient catalyst in the asymmetric allylic alkylation of l-acetoxy-l,3-diphenylprop-2-en (4) with malonate derivatives in the presence of AT,0-bis(trimethylsilyl)acetamide (BSA) and potassium acetate, affording enantioselectivity up to 96% and quantitative... [Pg.35]

The alkylation of benzene derivatives with methyl(vinyl)dichlorosilane (3) will be described in detail. Alkylation of monosubstituted benzenes such as toluene, chlorobenzene, and biphenyl at 75-80 C for 2 h afforded the corresponding alkylated products in 50-63% yields." ... [Pg.159]


See other pages where Biphenyl alkylation is mentioned: [Pg.87]    [Pg.87]    [Pg.403]    [Pg.316]    [Pg.328]    [Pg.87]    [Pg.87]    [Pg.403]    [Pg.316]    [Pg.328]    [Pg.240]    [Pg.242]    [Pg.242]    [Pg.268]    [Pg.116]    [Pg.117]    [Pg.129]    [Pg.86]    [Pg.42]    [Pg.348]    [Pg.256]    [Pg.130]    [Pg.85]    [Pg.316]    [Pg.535]    [Pg.940]    [Pg.6]    [Pg.139]    [Pg.161]    [Pg.188]    [Pg.189]    [Pg.15]    [Pg.146]   
See also in sourсe #XX -- [ Pg.172 , Pg.176 ]

See also in sourсe #XX -- [ Pg.263 ]

See also in sourсe #XX -- [ Pg.46 ]




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Alkyl biphenyl carboxylates, synthesis

Alkylation biphenyl with propylene

Alkylation of Biphenyl

Alkylations biphenyl, over zeolites

Biphenyl, alkylation over zeolites

Biphenyl, reductive alkylation

Catalysts biphenyl alkylation

Lower alkyl biphenyls

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