NOVELTY - Production of a biobased acrylic acid product involves combining a genetically engineered biomass comprising poly-3-hydroxypropionate, optionally a catalyst and a heat transfer fluid; and heating the biomass with the catalyst to convert the poly-3-hydroxypropionate to an acrylic acid product; where a yield of the acrylic acid product is at least 80% and the biobased carbon content of the acrylic acid product is at least 90%.    USE - For production of a biobased acrylic acid product such as biobased butyl acrylic acid ester product used in superabsorbent article (claimed).    ADVANTAGE - The process produces a high purity, high yield, biobased, acrylic acid product from renewable carbon resources. The process can be a continuous or a batch process. The acrylic acid product comprises less than 5 (preferably less than 3) wt.% side products.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) production (m2) of a biobased butyl acrylic acid ester product involving combining a genetically engineered biomass comprising poly-3-hydroxypropionate, n-butanol and a catalyst (c2); heating the biomass with the n-butanol and catalyst to reflux for 15-24 hours; and converting the poly-3-hydroxypropionate to a butyl acrylic acid ester product; where a yield of the acrylic acid ester product is at least 80% and the biobased carbon content of the acrylic acid product is at least 40%;    (2) an acrylic acid product produced by the process where the biobased carbon content is 100%;    (3) poly-3-hydroxypropionate biomass produced from renewable resources which is suitable as a feedstock for producing acrylic acid product, where the level of poly-3-hydroxypropionate in the biomass is greater than 50 wt.% of the biomass;    (4) article comprising the acrylic acid product produced by the process;    (5) production (m3) of an acrylic acid product involving polymerizing 3-hydroxypropionate or beta -propiolactone to poly-3-hydroxyprionate; and combining the poly-3-hydroxypropionate with a catalyst and a heat transfer fluid; and c) heating the poly-3-hydroxypropionate with the catalyst and heat transfer fluid to convert the poly-3-hydroxypropionate to an acrylic acid product, where a yield of the acrylic acid product is at least 50%.