NOVELTY - Synthesizing hydroxymethylfurfural (HMF) involves contacting a carbohydrate source with a solid phase catalyst; or contacting an HMF ester with an anionic solid phase catalyst; or contacting a fructose source with an organic acid and solid phase catalyst in a column to produce HMF ester, and deacylating the HMF ester.    USE - For synthesizing hydroxymethylfurfural (HMF) or its ester used in the synthesis of 2,5-furandicarboxylic acid (FDCA), levulinic acid and levulinate ester (claimed); as starting source for the formation of furan monomers which are used in the preparation of non-petroleum derived polymeric materials; for producing a wide range of products such as polymers, solvents, surfactants, pharmaceuticals and plant protection agents; as starting material or intermediate in the synthesis of wide variety of compounds such as furfuryl dialcohols, dialdehydes, esters, ethers, halides and carboxylic acids; as biofuel; and in the treatment of sickle cell anemia.    ADVANTAGE - The method allows synthesis and recovery of pure HMF and its derivative from hexose carbohydrate feedstocks such as fructose or high fructose corn syrup. The HMF prepared by the method has antibacterial and anticorrosive properties and hence is used as starting material or intermediate in the synthesis of wide variety of compounds such as furfuryl dialcohols, dialdehydes, esters, ethers, halides and carboxylic acids. The method allows large scale production of HMF with no impurities, side products and remaining starting materials. The method provides the compound with good selectivity and in high yields. The esters of HMF are stable and can be readily separated, potentially making them more useful than HMF itself. The method provides the compound with a purity of greater than or equal to 70 (preferably greater than or equal to 80, especially greater than or equal to 90)%. The solid phase catalyst used in the method does not dissolve in solvent and remain in the column. The use of column in the conversion of carbohydrate source to HMF or its ester allows the reaction to proceed and separate the product from the unreacted starting material or other unwanted side products that may form all in one step. The method minimizes and/or eliminates the formation of humins and polymeric by-products. The method is beneficial than other methods, as it eliminates the difficult task of isolating pure HMF for use as starting source. The method is simple and provides pure product which can be used as feeding source in the transformation of HMF esters to variety of useful derivatives and end products.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) method (P1) of preparing HMF esters involving combining materials comprising a carbohydrate source, a carboxylic acid, with or without an added catalyst to provide a reaction mixture; heating the reaction mixture to promote an acid-catalyzed reaction of the carbohydrate source to form a product mixture; and isolating an HMF ester from the product mixture;    (2) method (P2) of forming 2,5-furandicarboxylic acid (FDCA) involving reacting the HMF ester formed with an organic acid, cobalt acetate, manganese acetate and sodium bromide under elevated pressure and temperature to convert all of the HMF ester to FDCA;    (3) reducing the HMF ester formed by process (P1) involving heating a solution of the ester in a solvent, with catalyst, under elevated pressure and temperature to reduce the ester;    (4) method (P3) of synthesizing citrate esters involving contacting a solution having a citrate source and an alcohol with a solid phase catalyst by eluting the solution through a column packed with the solid phase catalyst to obtain an eluant;    (5) synthesizing a levulinic acid involving dissolving a carbohydrate source in a solution; passing the solution containing the carbohydrate through a column containing a solid phase catalyst; and eluting the levulinic acid from the column to obtain an eluant;    (6) method (P4) of synthesizing a levulinate ester involving dissolving a carbohydrate source in a solution containing acetic acid; passing the solution containing the carbohydrate through a column containing a solid phase catalyst; and eluting the levulinate ester from the column to obtain an eluant; and    (7) method (P5) of synthesizing a levulinate ester involving dissolving a carbohydrate source in a solution containing an alcohol; passing the solution containing the carbohydrate through a column containing a solid phase catalyst; and eluting the levulinate ester from the column to obtain an eluant containing a reaction product.