The present invention relates to: a catalyst for glycerin dehydration; a preparation method therefor; and an acrolein preparation method using the catalyst. According to one embodiment of the present invention, the catalyst is used in glycerin dehydration so as to exhibit high catalytic activity, a high yield and high acrolein selectivity, and has a characteristic in which carbon is not readily deposited, thereby having a long lifetime compared with that of a conventional catalyst.

Processes for the purification of bio-based acrylic acid to crude and glacial acrylic acid are provided. The bio-based acrylic acid is produced from hydroxypropionic acid, hydroxypropionic acid derivatives, or mixtures thereof. The purification includes some or all of the following processes: extraction, drying, distillation, and melt crystallization. The produced glacial or crude acrylic acid contains hydroxypropionic, hydroxypropionic acid derivatives, or mixtures thereof as an impurity.

Disclosed herein is a mixed phosphate catalyst for converting lactic acid to acrylic acid, which is characterized by a high conversion of lactic acid, a high selectivity for acrylic acid, a high yield of acrylic acid, and correspondingly low selectivity and molar yields for undesired by-products. This is achieved with a particular class of catalysts defined by a mixture of metal-containing phosphate salts. Further, the catalyst is believed to be stable and active for lengthy periods heretofore unseen in the art for such dehydration processes.

Processes for the purification of bio-based acrylic acid to crude and glacial acrylic acid are provided. The bio-based acrylic acid is produced from hydroxypropionic acid, hydroxypropionic acid derivatives, or mixtures thereof. The purification includes some or all of the following processes: extraction, drying, distillation, and melt crystallization. The produced glacial or crude acrylic acid contains hydroxypropionic, hydroxypropionic acid derivatives, or mixtures thereof as an impurity.

Processes for the catalytic dehydration of hydroxypropionic acid, hydroxypropionic acid derivatives, or mixtures thereof to acrylic acid, acrylic acid derivatives, or mixtures thereof with high yield and selectivity and without significant conversion to undesired side products, such as, acetaldehyde, propanoic acid, and acetic acid, are provided.

Methods for catalytically dehydrating hydroxypropionic acid, hydroxypropionic acid derivatives, or mixtures thereof to acrylic acid, acrylic acid derivatives, or mixtures thereof with high yield and selectivity and without significant conversion to undesired side products, such as, acetaldehyde, propionic acid, and acetic acid, are provided. The catalysts are mixed condensed phosphates.

Bio-based glacial acrylic acid, produced from hydroxypropionic acid, hydroxypropionic acid derivatives, or mixtures thereof and having impurities of hydroxypropionic acid, hydroxypropionic acid derivatives, or mixtures thereof, is polymerized to poly(acrylic acid) or superabsorbent polymer using the same processes as petroleum-derived glacial acrylic acid.

The present invention provides the use of a metal-doped hydroxyapatite catalyst for highly selective conversion of an alcohol to an aldehyde at low temperatures. More specifically, the invention provides the use of a silver-doped hydroxyapatite catalyst for the highly selective oxidative dehydrogenation of ethanol to acetaldehyde. The present invention also provides the method for converting ethanol to acetaldehyde using a silver-doped hydroxyapatite catalyst.

Hydroxypropionic acid, hydroxypropionic acid derivatives, or mixtures thereof are dehydrated using a catalyst and a method to produce bio-acrylic acid, acrylic acid derivatives, or mixtures thereof. A method to produce the dehydration catalyst is also provided.

A method for preparing a black phosphorus-modified copper-based catalyst for organic hydrogenation is provided. The method comprises: preparing the black phosphorus-modified copper-based catalyst by a hydrothermal, a stirring and a ball milling mode with a copper-based catalyst as the active component and black phosphorus as the auxiliary agent. The present invention greatly improves the catalytic performance of the copper-based catalyst while reducing the usage amount of the catalyst through the synergistic effect between black phosphorus and copper, which is beneficial to improving the economic benefits of industrial production. Finally, an energy-saving, environment-friendly and efficient organic hydrogenation catalytic process is achieved. The method of the present invention has the characteristics of high efficiency, simplicity, green and pollution-free reaction process and the like, so has high industrial application value.