Method for producing purified dialkyl-furan-2,5-dicarboxylate separation and solid liquid separation

#The invention relates to the processes for the production of purified dialkyl-furan-2,5-dicarboxylate (DAFD) and purified DAFD compositions made therefrom.

#Aromatic dicarboxylic acids such as terephthalic acid and isophthalic acid or their di-esters, dimethyl terephthalate as for example, are used to produce a variety of polyester products, important examples of which are poly(ethylene terephthalate) and its copolymers. The aromatic dicarboxylic acids are synthesized by the catalytic oxidation of the corresponding dialkyl aromatic compounds which are obtained from fossil fuels such as those disclosed in US 2006/0205977 A1. Esterification of these diacids using excess alcohol produces the corresponding di-esters has been disclosed in US2010/0210867A1. There is a growing interest in the use of renewable resources as feed stocks for the chemical industries mainly due to the progressive reduction of fossil reserves and their related environmental impacts.

#Furan-2,5-dicarboxylic acid (“FDCA”) is a versatile intermediate considered as a promising closest biobased alternative to terephthalic acid and isophthalic acid. Like aromatic diacids, FDCA can be condensed with diols such as ethylene glycol to make polyester resins similar to polyethylene terephthalate (PET) as disclosed in Gandini, A.; Silvestre, A. J; Neto, C. P.; Sousa, A. F.; Gomes, M. J. Poly. Sci. A 2009, 47, 295. FDCA has been prepared by oxidation of 5-(hydroxymethyl)furfural (5-HMF) under air using homogenous catalysts as disclosed in US2003/0055271 A1 and in Partenheimer, W.; Grushin, V. V. Adv. Synth. Catal. 2001, 343, 102-111. However, achieving high yields has proved difficult. A maximum of 44.8% yield using Co/Mn/Br catalysts system and a maximum of 60.9% yield was reported using Co/Mn/Br/Zr catalysts combination.

#FIG. 1 is a flow diagram of the process for making both FDCA and DAFD.

#FIG. 2 is a flow diagram describing the feed of raw materials to the esterification reactor.

#FIG. 3 is a flow diagram depicting the process of crystallizing, solid liquid separation, and isolating a DAFD composition, and optionally dissolving and subjecting the dissolved composition again to crystallization.

#It should be understood that the following is not intended to be an exclusive list of defined terms. Other definitions may be provided in the foregoing description, such as, for example, when accompanying the use of a defined term in context.

#As used herein, the terms “a,” “an,” and “the” mean one or more.

#As used herein, the term “and/or,” when used in a list of two or more items, means that any one of the listed items can be employed by itself or any combination of two or more of the listed items can be employed. For example, if a composition is described as containing components A, B, and/or C, the composition can contain A alone; B alone; C alone; A and B in combination; A and C in combination, B and C in combination; or A, B, and C in combination.