Tandem Synthesis of Ultra-High Molecular Weight Drag Reducing Poly-α-Olefins for Low-Temperature Pipeline Transportation.

Ultra-high molecular weight poly-α-olefins are widely used as drag reducing agents (DRAs) for pipeline transportation of oil and refined petroleum products. The synthesis of polyolefin DRAs is based on low-temperature Ziegler-Natta (ZN) polymerization of higher α-olefins. 1-Hexene based DRAs, the most effective at room temperature, typically lose DR activity at low temperatures.

Raman Spectroscopy Study of Structurally Uniform Hydrogenated Oligomers of α-Olefins.

The expansion of the range of physico-chemical methods in the study of industrially significant α-olefin oligomers and polymers is of particular interest. In our article, we present a comparative Raman study of structurally uniform hydrogenated dimers, trimers, tetramers, and pentamers of 1-hexene and 1-octene, that are attractive as bases for freeze-resistant engine oils and lubricants. We found out that the joint monitoring of the disorder longitudinal acoustic mode (D-LAM) and symmetric C-C stretching modes allows the quantitative characterization of the number and length of alkyl chains (i.

Chromium complexes bearing disubstituted organophosphate ligands and their use in ethylene polymerization.

The crystal structures of three unusual chromium organophosphate complexes have been determined, namely, bis(μ-butyl 2,6-di-tert-butyl-4-methylphenyl hydrogen phosphato-κO:κO')di-μ-hydroxido-bis[(butyl 2,6-di-tert-butyl-4-methylphenyl hydrogen phosphato-κO)(butyl 2,6-di-tert-butyl-4-methylphenyl phosphato-κO)chromium](Cr-Cr) heptane disolvate or {Cr(μ-OH)[μ-PO(OBu)(O-2,6-Bu-4-MeCH)-κO:κO'][PO(OBu)(O-2,6-Bu-4-MeCH)-κO][HOPO(OBu)(O-2,6-Bu-4-MeCH)-κO]}·2CH, [Cr(CHOP)(CHOP)(OH)]·2CH, denoted (1)·2(heptane), [μ-bis(2,6-diisopropylphenyl) phosphato-1κO:2κO']bis[bis(2,6-diisopropylphenyl) phosphato]-1κO,2κO-chlorido-2κCl-triethanol-1κO,2κO-di-μ-ethanolato-1κO:2κO-dichromium(Cr-Cr) ethanol monosolvate or {Cr(μ-OEt)[μ-PO(O-2,6-Pr-CH)-κO:κO'][PO(O-2,6-Pr-CH)-κO]Cl(EtOH)}·EtOH, [Cr(CHO)(CHOP)Cl(CHO)]·CHO, denoted (2)·EtOH, and di-μ-ethanolato-1κO:2κO-bis{[bis(2,6-diisopropylphenyl) hydrogen phosphato-κO][bis(2,6-diisopropylphenyl) phosphato-κO]chlorido(ethanol-κO)chromium}(Cr-Cr) benzene disolvate or {Cr(μ-OEt)[PO(O-2,6-Pr-CH)-κO][HOPO(O-2,6-Pr-CH)-κO]Cl(EtOH)}·2CH, [Cr(CHO)(CHOP)(CHOP)Cl(CHO)]·2CH, denoted (3)·2CH. Complexes (1)-(3) have been synthesized by an exchange reaction between the in-situ-generated corresponding lithium or potassium disubstituted phosphates with CrCl(HO) in ethanol. The subsequent crystallization of (1) from heptane, (2) from ethanol and (3) from an ethanol/benzene mixture allowed us to obtain crystals of (1)·2(heptane), (2)·EtOH and (3)·2CH, whose structures have the monoclinic P2, orthorhombic P222 and triclinic P-1 space groups, respectively.

(2,3)-1,4-Dioxa-spiro-[4.4]nonane-2,3-di-carb-oxy-lic and (2,3)-1,4-dioxa-spiro-[4.5]decane-2,3-di-carb-oxy-lic acids.

The title compounds, CHO and CHO, were formed by careful hydrolysis of the corresponding diethyl esters. Their single crystals were grown from an ethyl acetate/hexane mixture. Crystals of both compounds have monoclinic (2) symmetry with a single mol-ecule in the asymmetric unit.