A method of preparing an ester by reacting a carboxylic acid with a (C.sub.1-C.sub.36)alcohol in the presence of a catalyst that is suitable for preparing carboxylic acid esters of monomeric carboxylic acids in high yield. The method reduces by-products of the reaction, in particular esters of dimeric, trimeric and/or oligomeric carboxylic acids. The method requires a minimal excess of alcohol and does not require removal of water and/or carboxylic acid ester from the reaction mixture. The method is particularly suitable for the reaction of hydroxyalkylcarboxylic acids and fatty alcohols.

What is provided is a production method in which a vinyl acetate is reacted with a primary or secondary alcohol represented by Formula (1) and carbon monoxide to produce a first ester compound represented by Formula (2), and the first ester compound is reacted with an alcohol to produce a lactic acid ester represented by Formula (3) and an acetic acid ester represented by Formula (4).

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What is provided is a production method in which a vinyl acetate is reacted with a primary or secondary alcohol represented by Formula (1) and carbon monoxide to produce a first ester compound represented by Formula (2), and the first ester compound is reacted with an alcohol to produce a lactic acid ester represented by Formula (3) and an acetic acid ester represented by Formula (4).

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In methods for preparing an alkyl carboxylic acid ester according to an embodiment, a first reaction product is produced by reaction of a carboxylic acid stream and a first alcohol stream in a preliminary reactor. A second reaction product is produced by at least partially removing alcohol and water from the first reaction product. The second reaction product is esterified by reaction with a second alcohol stream in a main reactor. An alkyl carboxylic acid ester is recovered from the main reactor.

In methods for preparing an alkyl carboxylic acid ester according to an embodiment, a first reaction product is produced by reaction of a carboxylic acid stream and a first alcohol stream in a preliminary reactor. A second reaction product is produced by at least partially removing alcohol and water from the first reaction product. The second reaction product is esterified by reaction with a second alcohol stream in a main reactor. An alkyl carboxylic acid ester is recovered from the main reactor.

The present disclosure provides treprostinil derivatives that can act as prodrugs of treprostinil. The treprostinil derivatives can be used to treat any conditions responsive to treatment with treprostinil, including pulmonary hypertension, such as pulmonary arterial hypertension.

A continuous flow process for the preparation of one or more esters of lactic acid and 2-hydroxy-3-butenoic acid or α-hydroxy methionine analogues from a sugar in the presence of a solid Lewis acid catalyst and a solvent comprising an organic solvent and water. The invention provides a means for stabilizing a Lewis acid catalyst for use in a continuous reaction process wherein the water is present in an amount of up to or equal to 10 vol. % of the organic solvent.

A continuous flow process for the preparation of one or more esters of lactic acid and 2-hydroxy-3-butenoic acid or α-hydroxy methionine analogues from a sugar in the presence of a solid Lewis acid catalyst and a solvent comprising an organic solvent and water. The invention provides a means for stabilizing a Lewis acid catalyst for use in a continuous reaction process wherein the water is present in an amount of up to or equal to 10 vol. % of the organic solvent.

A continuous flow process for the preparation of one or more esters of lactic acid and 2-hydroxy-3-butenoic acid or α-hydroxy methionine analogues from a sugar in the presence of a solid Lewis acid catalyst and a solvent comprising an organic solvent and water. The invention provides a means for stabilizing a Lewis acid catalyst for use in a continuous reaction process wherein the water is present in an amount of up to or equal to 10 vol. % of the organic solvent.

Methods and systems for producing alkyl hydroxyalkanoates from hydroxycarboxylic acid recovery bottoms. The methods generally comprise the steps of obtaining a hydroxycarboxylic acid recovery bottom, adding a mono-alcohol to the hydroxycarboxylic acid recovery bottom to obtain a first mixture, heating the first mixture, optionally in the presence of a catalyst to form a reaction product, distilling the reaction product, and recovering an alkyl hydroxyalkanoate fraction.