No abstract

Africa SYNOPSISDi (2-ethylhexyl), di (2-octyl), dihexyl, and dibutyl furan-2,5-dicarboxylate were synthesized from furfural and characterized for their plasticizing abilities toward PVC by dynamic mechanical thermal analysis (DMTA) with di (2-ethylhexy1)phthalate (DOP) as the standard of reference. DMTA gave values for the depression of the glass transition temperature ( T,) per mass fraction of plasticizer, and it also yielded a set of parameters, relative to those for DOP, which describe the compatibility of the furan diesters with PVC. The efficiency in lowering T, as exhibited by di ( 2-ethylhexyl) furan-2,5-dicarboxylate is similar to that of its benzenoid analog, DOP, and was determined at 2.41 and 2.45OC per mass % plasticizer, respectively. All four furan diesters were found to be more compatible toward PVC than toward DOP, with dibutyl furan-2,5-dicarboxylate the most highly compatible. I NTRODU CTlO NFurfural is a valuable chemical that can be obtained in good from plant residues such as sugar cane bagasse, oat hulls, corn husks, or wood. Considering that these raw materials are renewable and largely underutilized, the use of furan derivatives for the polymer industry becomes an attractive alternative to petroleum-based technologies. World production of furfural is constrained by the limited demand for this compound, but production can be significantly expanded if new markets for furfural or its derivatives can be established.The present investigation deals with the synthesis of several long-chain furan diesters from furfural and the evaluation of these diesters as plasticizers for PVC. An incentive was whether an improvement would be realized in the plasticizing ability as a result of the polarity of the furan ring as compared to the benzene ring in conventional plasticizers. Application of the furan moiety as a functional element in a plasticizer for PVC is novel, and in order to compare its behavior to that of the benzene moiety, we initially synthesized and evaluated di ( 2-ethylhexyl ) furan-2,5-dicarboxylate, a molecule possessing a structure related to that of di(2-ethylhexyl ) phthalate, the well-established plasticizer known as DOP. Thermal analysis, in particular, DMTA, was the chosen technique for evaluating the plasticizing abilities of the furan diesters toward PVC. EXPERIMENTAL Instrumentation and MaterialsMelting points were determined on a Gallenkamp melting-point apparatus; melting and boiling points are uncorrected. Nuclear magnetic resonance spectra were measured in deuteriochloroform relative to tetramethylsilane as the internal standard. 'H-and 13C-NMR spectra were recorded on a Varian VXR 51 FT spectrometer at 300 MHz and a Varian FT 80 spectrometer at 80 MHz, respectively. All mass spectra and accurate mass measurements were recorded on a Varian MAT 311 A mass spectrometer. Refractive indices were measured on an Abe refractometer and densities of the furan diesters were determined with a dilatometer. Silica gel (0.063-0.200 1785

SYNOPSISThe compounds l,l-bis[5-(2-ethylhexyl, 2-octyl, hexyl, and butyl)carboxylate-2-f~-ryl)ethane, and 5,5'-dihexylcarboxylate-2,2' bifuran were synthesized from furfural and characterized for their plasticizing abilities toward polyvinyl chloride (PVC) by dynamic mechanical thermal analyses (DMTA) with di-(2-ethylhexyl) phthalate (DOP) as the standard of reference. DMTA gave values for the depression of the glass-transition temperature (T,) per mass fraction of plasticizer, and it also yielded a set of parameters, relative to those of DOP, which describe the compatability of the furan diesters with PVC. These values are compared to those of DOP and furan diesters incorporating only one furan ring in the molecular structure, which have previously been tested by this method. The difuran plasticizers are less efficient in lowering Tg than the monofuran plasticizers or DOP, with l,l-bis[5-(2-octyl)carboxylate-2-furyl]ethane the least efficient and l,l-bis(5-hexylcarboxylate-2-fury1)ethane the most efficient. On average the compatability toward PVC is better than that of DOP, and similar to that of analogous monofuran structures. I NTRO D U CTl ONWe have recently reported' our initial results on the synthesis of a range of long-chain furan diesters and the evaluation of these diesters as plasticizers for polyvinyl chloride (PVC). These studies are aimed at finding new applications for furfural, a compound available in potentially very large quantities from plant residues. Our initial results revealed that when a furan ring is substituted for the benzene ring of conventional plasticizers, an improvement in compatability toward PVC is realized, although little difference in plasticizing efficiency was found. We now communicate additional results in connection with our synthesizing endeavors toward new furan-based plasticizers incorporating two furan moieties, and an evaluation of the abilities of these diesters as plasticizers for PVC. EXPERIMENTAL Instrumentation and MaterialsMelting points were determined on a Gallenkamp melting point apparatus; melting and boiling points are uncorrected. Nuclear magnetic resonance (NMR) spectra were measured in deuteriochloroform relative to tetramethyl silane as internal standard. 'H-and 13C-NMR spectra were recorded on a Varian VXR 51 Fourier transform (FT)-spectrometer at 300 MHz and a Varian FT 80 spectrometer at 80 MHz, respectively. All mass spectra and accurate mass measurements were recorded on a Varian MAT 311 A mass spectrometer. Refractive indices and densities of the difuran diesters were measured on an Abe refractometer and with a dilatometer, respectively. Silica gel (0.063-0.200 mm, Merck), was used for column chromatography and analytical thin layer chromatographic separations were performed on silica gel plates (0.2 mm, Merck 60 F254). All solvents were purified and fractionally distilled prior to use, and petroleum ether refers to the fraction boiling at 40-60°C. The paste PVC 1837

SYNOPSISButyl, hexyl, and 2-ethylhexyl diesters of l,l-bis(5-carboxyl-2-furyl)-2,2-dichloroethene, hexyl and 2-ethylhexyl diesters of 1,1-bis(5-carboxyl-2-furyl)ketone, and the hexyl diester of l,l-bis(5-carboxyl-2-furyl)methane were synthesized from furfural and evaluated for their plasticizing abilities toward PVC, by the application of dynamic mechanical thermal analysis and [di(2-ethylhexyl) phthalate] as a standard of reference. 0 1995

1992 ring closure reactions ring closure reactions O 0130 34 -082 Intramolecular Oxypalladation and Cross-Coupling of Acetylenic Alkoxides. -The acetylenic alcohols (I) or the o-alkynylphenols (IV) are coupled with the organic halides (II) or (V) in the presence of a palladium complex to form the cyclic ethers (III) and (VI) respectively. -(LUO, F.-T.; SCHREUDER, I.; WANG, R.-T.; J.