PREPARATION OF MULTIFUNCTIONAL ORGANOLITHIUM INITIATOR IN CYCLOHEXANE SOLUTIONS

Multifunctional organolithium initiator was prepared in cyclohexane solvent. The process started with adding the cyclohexane solution of butadiene to naphthalene-lithium in batches to produce butadiene oligomer dilithium with 4-8 butadiene repeating units. In the first feeding, the maximum loading of cyclohexane and the minimum concentration of butadiene cyclohexane solution must be controlled under Vcyclohexane 〈 1.33 VTHF and p 〉 40.6cN. Then, SnCl4 was added and eventually the multifunctional organolithium initiator containing Sn atom was synthesized through coupling reaction. Experiment results showed that adding the cyclohexane solution in batches was effective in overcoming some difficulties, such as insolubility of naphthalene-lithium in cyclohexane, low efficiency of naphthalene-lithium in initiating butadiene. In practice, benzene can be replaced by cyclohexane completely, which can not only reduce environmental pollution from benzene, but also overcome the difficulty of solvent recovery caused by similar boiling point between benzene and cyclohexane. Prepared with multifunctional organolithium containing Sn atom as initiator, the star-shaped solution polymerized styrene-butadiene rubber （star S-SBR） with better vulcanization performances, lower rolling resistance and higher wet-skid resistance was obtained.