Poly- butyl lithium

There are some indications that the situation described above has been realized, at least partially, in the system styrene-methyl methacrylate polymerized by metallic lithium.29 29b It is known51 that in a 50-50 mixture of styrene and methyl methacrylate radical polymerization yields a product of approximately the same composition as the feed. On the other hand, a product containing only a few per cent of styrene is formed in a polymerization proceeding by an anionic mechanism. Since the polymer obtained in the 50-50 mixture of styrene and methyl methacrylate polymerized with metallic lithium had apparently an intermediate composition, it has been suggested that this is a block polymer obtained in a reaction discussed above. Further evidence favoring this mechanism is provided by the fact that under identical conditions only pure poly-methyl methacrylate is formed if the polymerization is initiated by butyl lithium and not by lithium dispersion. This proves that incorporation of styrene is due to a different initiation and not propagation. 

Vinylfuran did not polymerize with butyl lithium in hexane or tetrahydrofuran. Traces of resinous materials were isolated. Their spectra indicated complicated structures and not poly(2-vinylfuran). 

An alternative synthesis of a thermally stable cyclopentadienyl functionalized polymer involved ring bromination of poly(oxy-2,6-diphenyl-l,4-phenylene), followed by lithiation with butyl lithium to produce an aryllithium polymer. Arylation of 2-norbornen-7-one with the metalated polymer yielded the corresponding 2-norbornen-7-ol derivative. Conversion of the 7-ol to 7-chloro followed by treatment with butyl lithium generated the benzyl anion which undergoes a retro Diels-Alder reaction with the evolution of ethylene to produce the desired aryl cyclopentadiene polymer, 6. 

An alternative route to poly(m-carborane-siloxane) rubbers is via the condensation reaction between w-carborane di-hydrocarbyl-disilanol and a bis-ureidosilane.20 This mild reaction allows the incorporation of desired groups into the polymer via both the dihydrocarbyl-disilanol and the bis-ureidosilane (see scheme 8). The first step involves the formation of the carborane silanol from the butyl lithium carborane derivative. The bis-ureidosilane is prepared from the phenyl isocyanate (see step 2), and the final step involves reacting the dihydrocarbyl-disilanol with bis-ureidosilane. 

Materials. Methylene 4,4 -diphenyldiisocyanate (MDI, Mobay) was recrystallized from cyclohexane. Toluenediisocyanate (TDI— represents mixture of 2,4- and 2,6-isomers in 80/20 ratio), p-toluidine (Aldrich) and aniline (Aldrich) were purified by vacuum distillation before use. Diphenylmethane, tert-butyl peroxide (TBP), 4-bromoaniline, butyl lithium in hexane, and ethyl chloroformate, were obtained from Aldrich and used as received. Spectrograde tetrahydrofuran (THF) and benzene from Burdick and Jackson were used as received. Poly(tetramethylene ether glycol) with MW 1000 was obtained from polysciences and dehydrated under a rough vacuum at 50 °C for 24 h. 

A Kjeldahl flask was charged with ,/V -dimethyl-1,6-diaminohexane (5.75 mmol) dissolved in 10 ml of THF and then treated with the dropwise addition of -butyl-lithium (5.75 mmol) while vigorously stirring. This solution was then treated with chlorotrimethylsilane (5.75 mmol) and stirred at ambient temperature for 30 minutes and then filtered off through a poly(tetrafluoroethylene) (PTFE) filter and 15 mL of the filtrate charged into a 150-ml glass bottle. This aliquot was then treated with tetramethylethylene diamine (4.23 mmol) and n-butyllithium (4.23 mmol) and used immediately as a polymerization initiator. 

Poly-methyl-sorbate 2-methyl-butyl-lithium R s COOH 1 ch3-c-h... 

Poly-methyl-sorbate n-butyl-lithium-menthyl-ethyl-ether 1R, 3R, 4S R CHj-COOH COOH 1... 

Poly-butyl- /S-styryl-acrylate 2-methyl-butyl-lithium R S H-C-CSHS... 

The strategy of incorporating silicon as a reactive component in the polymeric system to attain flame retardancy has been explored. For example, Ebdon et al. carried out silylation to the polystyrene using //-butyl lithium in the presence of tetramethylethylenediamine, followed by reaction with trimethylchlorosilane, dichlorodimethylsilane, or trichloromethylsilane, as shown in Scheme 8.1. Poly(vinyl alcohol) films have also been modified with chlorosilanes (Scheme 8.1). 

Rossi has synthetized block copolymers polyisoprene-poly(vinyl-2-pyridine) and polyisoprene-poly(vinyl-4-pyridine) of various composition and molecular weight by anionic polymerization under high vacuum205, 208. The polymerization in THF dilute solutions with Cumylpotassium as initiator yielded a 1,2 + 3,4-microstructure of the polyisoprene block. The polymerization in toluene solutions with sec-butyl-lithium as initiator yielded a 1,4-c/s-microstructure of the polyisoprene block. 

Dilithium or disodium areneditellurolates were alkylated with methyl iodide3, dimethyl sulfate4, or diethyl sulfate4. The areneditellurolates were prepared from the corresponding dibromides and tert.-butyl lithium in tetrahydrofuran and treatment of the resulting mixture with powdered tellurium3, or by the reduction of poly(l,4-phenylene ditellurium) with sodium borohydride in ethanol/benzene4. 

Poly(l,4-phenylene Ditellurium)1 Under nitrogen, a solution of 1 mol of 1,4-dibromobenzene is cooled to — 15° with stirring, a solution of 22 mol of butyl lithium in hexane is added dropwise followed by 1 mol of finely ground tellurium, and the mixture is stirred at 20° until all of the tellurium has dissolved. To this mixture is added 2 mol of butyl lithium followed by 1 mol of powdered tellurium. When all of the tellurium has dissolved, 2 mol of water and then 2 mol of triethylaminc arc added. The resultant tellurolate is oxidized by addition of an aqueous solution of potassium hexacyanoferrate(Ill) yield 54% reddish-brown, amorphous powder. 

Butler, Thomas, and Tyler (9) have reported on the stereo-specific polymerization of N,N-disubstituted acrylamides by alkyl lithiums. Overberger and Schiller (51) reported on the preparation of crystalline poly-/-butyl vinyl ketone by anionic catalysts in toluene at room temperature. 

The author [2] prepared poly(a-methylstyrene-b-styrene) copolymers using s-butyl lithium and triisobutylaluminum. 

A catalyst combination consisting of the barium salt of tri(ethyleneglycol)ethyl ether, Ba(0CH2CH20CH2CH20CH2CH3)2, with tri-n-octyl aluminum and n-butyl lithium has been used to prepare random poly(styrene-co-butadiene) containing a high butadiene transcontent. These polymers were designed to be co-cured with natural rubber and used as components in automotive tires. 

Poly(cx-methylstyrene) having a Mn > 300,000 daltons with of PDI < 1.06 was prepared using sec-butyl lithium. The process entails initially treating the monomer with sec-butyl lithium to dry and to neutralize impurities while monitoring this process by UV. The monomer was then re-treated with butyl lithium, THF, and toluene and polymerized 24 hours. The material is intended for inertial confinement chambers in fusion experiments. 

Moore [1] prepared polystyrene having a Mn of 130,000 daltons with a PDI of 1.05 by initially drying the monomer and neutralizing impurities with n-butyllithium prior to polymerization. n-Butyl-lithium was also used with potassium t-amyloxide by Malanga [2] in preparing ultra-pure poly(a-methylstyrene). 

Poly(butadiene-b-a-methylstyrene-b-styrene) was prepared by Tung [4] using sec-butyl-lithium and l,3-di(l-phenylethenyl)benzene. 

Poly(ot-methylstyrene-co-styrene) was previously prepared by Desbois [5] using s-butyl lithium and triisobutylalumimim. 

Living anionic polymerization of 4-vinylphenol was performed after transformation of the phenolic hydroxy group into trialkybilyl ether group and removal of the protection group after polymerization [125]. n-Butyl lithium was used for the synthesis of poly[2-hydroxy-4-methacryloyloxybenzophenone] [61] (102) or HALS terminated poly(methyl methacrylate) [126]. 2-Hydroxy-4-methacryloyl-... 

Polymerization of I. I was polymerized in flame-dried equipment under N 2 at -40 °C as follows. A 25-mL round-bottom flask equipped with a poly(tetra-fluoroethylene) (Teflon)-covered magnetic stirring bar and rubber septum was charged with I (1.2 g, 10.9 mmol) (5, 6), THF (10 mL), and either HMPA (5 drops) or TMEDA (5 drops). n-Butyllithium (0.8 mL, 1.2 M, 0.96 mmol) was added slowly to this mixture. The mixture quickly became thick. The mixture was stirred for 1 h at -40 °C and then warmed to -20 °C, and saturated aqueous ammonium chloride was added. The organic layer was separated, washed with brine and water, and dried over molecular sieves (4 A). After filtration, the solvent was removed by evaporation under vacuum 1.10 g (92% yield) of polymer was isolated. The yields of polymer ( 2%) and their spectral properties were identical regardless of whether HMPA or TMEDA was used as cocatalyst. With n-butyllithium-TMEDA, a polymer with Mw and Mn of 158,000 and 69,000, respectively, was obtained, whereas with n-butyl-lithium-HMPA, a polymer with My, and M of 120,000 and 30,400, respectively, was isolated. 

Polymerization of 2-triethylsilyl-l, 3-butadiene initiated by n-butyl-lithium in hexane yielded (E)-l, 4-poly(2-triethylsilyl-l, 3-butadiene). The molecular weight distribution (as determined by gel permeation chromatography) of the polymers depended on the ratio of monomer to initiator concentrations. Polymers of low polydispersity (Mu [weight-average molecular weight]/Mn [number-average molecular weight] = 1.3-1.6) and with up to 110,000 w re obtained. The... 

The formation of the polymeric carbanions 81 of the fluorenyl-type is successful starting from the poly(para-phenylene) ladder polymer 71 with butyl-lithium as metallating agent. The degree of lithiation lies in the range of 90-95% (NMR). The UV/VIS absorption spectrum of these polymeric anions (81) is comparable with that of the 9-phenylfluorenyl anion and indicates the presence of mostly localized (anionic) sub-structures [101]. 

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