2974-90-5

Usage

Uses

3,4''-Dichlorobiphenyl is a polychlorinated biphenyl (PCB) congeners.

Upstream product

• 10312-71-7 1,6-bis-(4-chlorophenyl)-3,4-diacetyl-1,5-hexazadiene 
• 108-90-7 chlorobenzene 
• 67-63-0 isopropyl alcohol 
• 108-95-2 phenol 
• 16606-02-3 2,4',5-Trichlorobiphenyl 
• 1679-18-1 4-Chlorophenylboronic acid 
• 29682-41-5 2,5-dichloroiodobenzene 
• 106-47-8 4-chloro-aniline 
• 79991-27-8 1-p-chlorophenyl-3,4-diacetyl-1-tetrazene 
• 673-41-6 p-chlorobenzenediazonium tetrafluoroborate 

Downstream Products

• 1290615-12-1 C₇₂H₅₀N₄ 
• 92-52-4 biphenyl 

Relevant academic research and scientific papers

Visible-Light-Promoted, Catalyst-Free Gomberg-Bachmann Reaction: Synthesis of Biaryls

Biaryls were synthesized via a novel visible-light-promoted Gomberg-Bachmann reaction that does not require a photosensitizer or any metal reagents. The formation of an electron donor-acceptor complex between aryl diazonium salts and pyridine allows, under visible-light irradiation, the synthesis of biaryls in moderate-to-high yields.

Regularities of Pd/C-catalyzed reduction of trichlorobiphenyls with 2-propanol in basic medium

Reduction of a series of trichlorobiphenyls with 2-propanol in basic medium catalyzed by Pd/C has been studied. Regioselectivity of the reduction has been determined. In the studied cases, the chlorine atom in para or meta positions of the more substituted ring has been more reactive. Using isotope labeling, it has been demonstrated that the reaction occurs via the stage of 2-propanol dehydration on palladium catalyst, followed by catalytic hydrogenation of the polychlorinated biphenyls.

Hydrocarbons and chloroaromatics from anilines and n-butyl nitrite

A single reagent, i.e. n-butyl nitrite, can be used to oxidize an aromatic amine, or the corresponding N-methylene derivative, to a diazo compound followed by its subsequent reduction to hydrocarbon in a single batch.Alternatively, a chloro derivative can be obtained if carbon tetrachloride is used as the solvent.The reactions appear to be general and complete product identification was accomplished.

Polar Effects in Reactions of Carbon-Centered Radicals with Diazonium Salts: Free-Radical Diazocoupling

Carbon-centered radicals react with diazonium salts by addition, leading under reductive conditions to azo derivatives (free-radical diazocoupling), or by electron-transfer in chain processes.The reaction is highly sensitive to polar effects and it has been investigated by three different processes: (i) alkyl radicals, generated from alkyl iodides, H2O2, Fe(II) salt, and DMSO, have been utilized to develop a new general synthesis of alkylarylazo compounds; (ii) the reaction of aryl radicals with diazonium salts in the presence of Ti(III) or Fe(II) salts has been investigated, also in relation to the fact that the reaction products (azoarenes and biaryls) are often detected as side products in classical organic reactions of diazonium salts, catalyzed by Cu(I) salts, such as the Sandmeyer, Meerwein, and Pschorr reactions; (iii) adducts from addition of aryl radicals to vinyl acetate or vinyl ether react with diazonium salts either by diazocoupling reaction or by electron-transfer; a general synthesis of arylazo compounds has been developed.

Vapour-phase Chemistry of Arenes. Part 13. Reactivity and Selectivity in the Gas-phase Reactions of Hydroxyl Radicals with Monosubstituted Benzenes at 563 K

The reactions of hydroxyl radicals with benzene derivates C6H5Z (Z = H, Me, F, Cl, Br, I, CF3, or CN) have been studied in a flow reactor at 563 K in nitrogen, using the thermolysis of ButOOH as a source of .OH.Under these conditions there are two product-forming pathways.The major one involves hydrogen abstraction to give aryl radicals ZC6H4. (II) as the first step; depending on Z, its displacement to form phenol may also occur.Relative rates for hydrogen abstraction were determined in competition experiments using side-chain hydrogen abstraction from added toluene as a reference.This resulted in the order (for Z =): 1,8(Me), 1.0(H), 0.47(F), 0.29(Cl), 0.34(CF3), 0.20(CN), consonant with the electrophilic nature of .OH.The site selectivity of hydrogen abstractions was determined by scavenging part of the aryl radicals (II) with iodine.A Hammett plot, using ? constants for meta and para positions, led to ρ -1.0.The features of hydrogen abstraction by .OH are discussed and compared with those for the analogous reaction of Cl.The formation of phenol was found to decrease in importance in the order F, Cl, Br, and I.This result is rationalized on a thermochemical kinetic basis.

Gas-phase thermolysis of tert-butyl hydroperoxide with benzene and chlorobenzene in the temperature range 200-300 deg C

Thermolysis of tert-butyl hydroperoxide (1) in nitrogen with an excess of benzene in the temperature range 200-300 deg C, leads to biphenyl (2) as the only observable benzene-derived product.With chlorobenzene, dichlorobiphenyls (4) are formed, together with chlorobiphenyl (5), ca. 12percent on 4, and phenol (20-25percent on 4); chlorophenols are not produced.The use of ca. equimolar quantities of iodine based on 1 results in formation of iodobenzene (3) and chloroiodobenzenes (7), respectively, at the expense of biaryl.In air, chlorobenzene and 1 produce chlorophenols (8), biaryl then being a minor product.Hydroxyl radicals produced from 1 abstract hydrogen from benzene to give phenyl radicals (Ph.) which, in notrogen, arylate benzene.From isomer distributions of 7 and of 4 it is inferred that hydrogen abstraction from chlorobenzene leads to chlorophenyl radicals, with a ratio o/m/p ca. 24/52/24.With chlorobenzene, ipso substitution, PhCl + .OH -> PhOH, also takes place.In the presence of oxygen or iodine, formation of biaryls involves irreversible addition of (chloro)phenyl radical, the intermediate adduct radicals reacting with oxygen or iodine.In nitrogen, however, the first step in arylation is reversible.Apart from undergoing O-O bond homolysis, 1 is attacked by .Me (formed from Me3CO.) and, to some extent, by aryl radicals.A large arene/1 intake ratio (>100), or the addition of either iodine or air suppresses - or even prevents - free-radical-induced decomposition of 1.

Phase-Transfer-Catalyzed Gomberg-Bachmann Synthesis of Unsymmetrical Biarenes: A Survey of Catalysts and Substrates

Two problems have hindered the Gomberg-Bachmann (GB) and Pschorr reactions of arenediazonium cations: the instability of the arenediazonium salts and side reactions.Arenediazonium tetrafluoroborate and hexafluorophosphate salts can be prepared in high yield and purity and can be stored safely.Unfortunately, these salts are insoluble in most nonpolar organic solvents.Crown ether complexation or other phase-transfer (pt) catalytic methodology can ameliorate this situation, and reactions conducted by the approaches outlined herein often afforded coupling or cyclization products in high yield and corresponding purity.The use of crown ethers, quarternary 'onium salts, lipophilic carboxylic acid salts, and even the polar cosolvent acetonitrile increase the utility of the ptGB reaction dramatically.Sixty examples of couplings are reported along with an assessment of selectivities.A number of examples are also presented of phase-transfer-type Pschorr cyclizations.In the latter case, the use of potassium superoxide, KO2, is introduced to suppress indazole formation.

PALLADIUM(II)-CATALYZED OXIDATIVE COUPLING OF ARENES BY THALLIUM(III)

Oxidation of benzenes with electron-donating and moderate electron-withdrawing substituents by thallium(III) trifluoroacetate in the presence of catalytic amounts of palladium(II) acetate affords biaryls in good yields.The GLC study of the isomer distribution has shown that 4,4'-biaryls are the major products.Thus, the 4,4'-biaryls can be easily isolated either by recrystallization or column chromatography.The competitive experiments and kinetic study using arenes and arylthallium derivatives as starting materials as well as quenching experiments have demonstrated the first step of the reaction to be fast thallation of arene to form arylthallium intermediate ArTl(OOCCF3)2.The latter undergoes the rate-determining transmetallation step reacting with monomeric complex Pd(OAc)2, which is formed upon depolymerization of trimer Pd3(OAc)6.Subsequent fast decomposition of arylpalladium species gives the final reaction products.The thallation of arene and substitution of TlIII for PdII in ArTl(OOCCF3)2 are characterized by the slopes of Hammet plots of -5.6 (?+) and -3.0 (?), respectively.

Aryl radicals from hexazadienes and tetrazenes

Aryl radicals are produced from both ends of the hexazadienes 1 and 2 and from the tetrazene 3, either thermally or photolytically.They attack aromatic compounds in the nucleus, the yield of biaryl being in the range 40-70percent, though it can be made nearly quantitative by using m-dinitrobenzene as additive.The aryl radicals also oxidize 2-propanol to acetone, the reaction products being the halogenobenzene and 1,2-diacetylhydrazine.Photolysis of 1 goes mainly by way of the tetrazene 3, and this may also be a significant pathway in the thermal reaction.Azodiacetylis an intermediate in the thermal reaction of 1 with 2-propanol and may be generally so in all its reactions.Radical induced decomposition is believed to be important in the reactions of 1, 2, and 3, and it is probably responsible for the formation of 1-acetyl-1-arylhydrazines, routinely produced in yields up to 25percent.