Hydroxyapatites as Catalysts

Hydroxyapatite, a calcium phosphate compound, has the unique characteristic that its chemical composition can be altered without destroying its fundamental crystalline structure. Other elements can be substituted for some of its calcium or phosphate and some components may even be left out, allowing significant scope for variation in its physicochemical attributes.

Because of this unique tolerance for fine tuning of its component elements and its ability to endure significant distortions of its crystal lattice while still maintaining its basic structure, hydroxyapatite offers a wide range of possibilities as a catalyst for use in chemical engineering applications, through adjustments to its morphological configuration and its calcium to phosphorous ion ratio that can be made according to the method of synthesis.

By developing technology to control hydroxyapatite’s various characteristics, Sangi has successfully achieved catalyzing functions that are not present in other catalysts. This technology has progressed from beaker scale to industrial scale, making it possible to manufacture the catalysts at an industrial level.

Synthesis of Industrial Chemicals from Biomass-derived Raw Materials

Sangi’s research into catalysts began in the 1990s with the synthesis of bio-gasoline, a chemical mixture very close to high-octane fuel, obtained using plant-derived ethanol as raw material. This research was then taken further to focus on synthesis of a number of valuable chemical products from bio-ethanol and other biomass-derived raw materials.

Apatite catalysts, with their finely controlled properties, possess a variety of catalyzing functions not found in existing solid catalysts. For example, they make it possible to selectively synthesize higher alcohols from ethanol, with selectivity of over 70% in the case of n-butanol, a product vitally important in the chemical industry as a material for paint solvents and plasticizing agents, and superior in chemical properties to ethanol as a replacement for gasoline. Sangi’s technology makes it possible to manufacture, from environmentally friendly, biomass-derived ethanol, a range of industrial chemicals that are still commercially fossil fuel derived.

In addition, Sangi is working collaboratively with university researchers to selectively synthesize acrylic acid from lactic acid using hydroxyapatite catalysts. Since lactic acid is currently produced from biomass-derived materials, this raises the prospect of acrylic acid, a key raw material for the production of super-absorbent polymers and a wide range of products, being synthesized in future from an environmentally friendly source.

The reaction synthesizing n-butanol from ethanol using a hydroxyapatite catalyst

The reaction synthesizing n-butanol from ethanol using a hydroxyapatite catalyst