Copper(II) complexes with weakly coordinating counter anions can be utilized as highly efficient catalysts for the synthesis of poly(2-methylpropene) ("polyisobutene") with a high content of terminal double bonds. These copper(II) compounds are significantly more active than the manganese(II) complexes described previously, can be applied in chlorine-free solvents such as toluene, are easily accessible, and can be handled at room temperature and in laboratory atmospheres for brief periods, but they are sensitive to excess water, thereby losing their catalytic activity. Replacing the acetonitrile ligands by benzonitrile ligands improves the solubility and catalytic activity in nonpolar and nonchlorinated solvents. However, the benzonitrile copper(II) compounds have lower thermal stability than their acetonitrile congeners.

Transportation of hydrocarbons and water in long subsea flow lines from satellite fields to a platform or to an onshore facility presents new challenges in the control of gas hydrates, corrosion, and mineral scale. Gas hydrates form at high pressure and low temperature and are a common problem in offshore wet gas pipelines due to low seabed temperatures and elevated pressures in these remote subsea developments. Monoethylene glycol (MEG) is widely used as a thermodynamic hydrate inhibitor in these developments to manage the risk of hydrate formation during production and transportation of multiphase fluids from subsea wells. Due to large amounts of MEG required for effective hydrate control, it is necessary to recycle and re-use it. The main processes for recycling of MEG are regeneration and reclamation. Typical conditions of regeneration and reclamation processes are ambient to vacuum pressures and temperatures in the range of 120°C −150°C1. In addition to the use of MEG for hydrate control, corrosion inhibitors are also applied for corrosion control in the subsea pipelines and infrastructure. These corrosion inhibitors must be able to perform under high shear and highly corrosive environments without losing their effectiveness after having been subjected to the system conditions present in the MEG regeneration process. Inappropriate selection of corrosion inhibitors for MEG based applications can lead to severe fouling/formation of solids, emulsion and foaming issues in the receiving facilities. The corrosion inhibitors developed for use in facilities operating with glycol regeneration systems should remain active after multiple MEG Regeneration Unit (MRU) cycles without causing fouling/formation of solids, emulsion and foaming. The current paper presents MRU compatible corrosion inhibitors developed based on the stringent testing methods adopted from real time MRU process.

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Acetonitrile ligated molybdenum (III) complexes of the structure [MoCl(NCCH 3 ) 5 ] 2þ bearing different weakly coordinating anions [B(C 6 F 5 ) 4 ] À (WCA a), [B{C 6 H 3 (m-CF 3 ) 2 } 4 ] À (WCA b) and [(C 6 F 5 ) 3 B-C 3 H 3 N 2 -B(C 6 F 5 ) 3 ] À (WCA c) were applied as homogeneous catalysts of the polymerization of isobutylene. High monomer conversions were obtained in short reaction times (<30 min). The molecular weight of the resulting polyisobutylene is nearly independent of parameters such as temperature, solvent, monomer concentration, but is strongly influenced by the type of WCA and by chain transfer reactions which were observed in these systems. Highly reactive low molecular weight polyisobutylenes (M n < 2000 g/mol) were obtained with a high content of exo double bond end groups as shown by 1 H NMR analysis. Furthermore, experiments were performed to reduce the isomerization of these exo end groups into other internal double bonds by varying the polymerization parameters.

Dedicated to Süd-Chemie on the occasion of its 150th anniversary Commercial polyisobutenes [Eq. (1)] can be classified into three groups based on their molecular weights, characteristic properties, and varied applications.[1] The high-molecularweight (M n = 300 kg mol À1 ) polyisobutenes are rubber-like and thus have applications in the rubber goods industry and are used for insulation purposes. Mid-range polyisobutenes with molecular weights ranging from M n = 40-120 kg mol À1 are used in glues, sealants, and as chewing-gum base. The lowmolecular-weight polyisobutenes have weights from M n = 0.5-5 kg mol À1 and are colorless, honeylike viscous liquids. The so-called highly reactive polyisobutenes belong to this class of polymers; they have more than 60 % terminal (exo) C = C bonds (usually 70-80 %) and are of significant commercial interest. After functionalization, these olefins are applied as lubricants or oil additives. [2,3] It has been known for many years that polymerization of 2-methylpropene ("isobutene") can be achieved by means of cationic initators like Brønsted or Lewis acids. Typical catalysts are AlCl 3 , BCl 3 , or BF 3 in combination with water or alcohols as co-initiator. Solvents like methyl chloride, dichloromethane, and n-hexane can be used in a temperature range of À20 8C to À80 8C, depending on the desired molecular weight of the polymeric product. Polymerization under these conditions is fast and exothermic, but it is expensive to maintain the reaction temperatures. Each year, several 100 000 t of highly reactive polyisobutene are produced industrially using these methods.Recently, a new type of catalyst has been described, consisting of solvent-ligated Mn II complexes with bulky, noncoordinating counterions. These compounds are applicable for the polymerization of 2-methylpropene. [4][5][6][7] The great advantage of these systems is that polymerization takes place at room temperature or above. [4][5][6][7] We have now found that certain molybdenum(III) compounds significantly surpass the Mn II complexes in activity and have other important advantages that are desirable for the preparation of highly reactive polyisobutenes. Herein, these Mo III complexes and their applications in polymerization catalysis are described.The complexes 1-3 are obtained in three steps starting by reaction of Mo 2 (O 2 CCH 3 ) 4 with a fourfold stoichiometric excess of HCl and KCl.