Catalytic Dehydration Of Hydroxypropionic Acid And Its Derivatives

A method of making acrylic acid, acrylic acid derivatives, or mixtures thereof comprising contacting the following compositions under conditions including a water partial pressure and a temperature:

• a gas mixture comprising:
• a) hydroxypropionic acid, hydroxypropionic acid derivatives, or mixtures thereof;
• and
• b) water vapor;
• with
• a dehydration catalyst consisting essentially of one or more amorphous phosphate salts, one or more crystalline phosphate salts, and one or more non-phosphate salts;
• wherein said one or more crystalline phosphate salts and said one or more non-phosphate salts are substantially chemically inert to said one or more amorphous phosphate salts;
• wherein said one or more amorphous phosphate salts consist essentially of:
• i) one or more monovalent cations, and
• ii) one or more phosphate anions selected from the group represented by empirical formula (I):
• [H2(1−x)PO(4−x)]− (I);
• wherein x is any real number equal to or greater than 0 and equal to or less than 1;
• wherein said one or more amorphous phosphate salts are neutrally charged;
• or any hydrated form of said one or more amorphous phosphate salts, and mixtures thereof;
• wherein said one or more crystalline phosphate salts consist essentially of:
• i) one or more polyvalent cations, and
• ii) one or more phosphate anions selected from the group represented by molecular formula (II):
• [H(f−2g−h)PfO(4f−g)](2f+h)− (II);
• wherein f is a positive integer;
• wherein g is a positive integer or zero;
• wherein h is an integer;
• wherein (f−2g−h) is equal to or greater than zero;
• wherein (4f−g) is greater than zero;
• wherein (2f+h) is greater than zero;
• wherein (4h/f) is equal to or greater than −2 and equal to or less than 1;
• wherein said one or more crystalline phosphate salts are neutrally charged;
• or any hydrated form of said one or more crystalline phosphate salts, and mixtures thereof;
• wherein said one or more non-phosphate salts consist essentially of:
• i) one or more polyvalent cations, and
• ii) one or more non-phosphate anions selected from the group represented by molecular formulae (III) and (IV):
• [H(a−2b)ScO(4c−b)](2c−a)− (III)
• [Ta2dO(5d+e)]2e− (IV);
• wherein a and b are positive integers or zero;
• wherein c, d, and e are positive integers;
• wherein (a−2b) is equal to or greater than zero;
• wherein (2c−a) is greater than zero;
• wherein said one or more non-phosphate salts are neutrally charged;
• or any hydrated form of said one or more non-phosphate salts, and mixtures thereof;
• wherein the water partial pressure during said contacting step in said gas mixture is equal to or greater than the water partial pressure at the triple point of said one or more amorphous phosphate salts;
• wherein said contacting step is performed at a temperature equal to or greater than the temperature at the triple point of said one or more amorphous phosphate salts;
• and
• whereby said acrylic acid, acrylic acid derivatives, or mixtures thereof is produced as a result of said water vapor and said hydroxypropionic acid, hydroxypropionic acid derivatives, or mixtures thereof being contacted with said dehydration catalyst.

The method of making acrylic acid, acrylic acid derivatives, or mixtures thereof comprising contacting the following compositions under conditions including a water partial pressure and a temperature:

• a gas mixture comprising:
• a) hydroxypropionic acid, hydroxypropionic acid derivatives, or mixtures thereof;
• and
• b) water vapor;
• with a dehydration catalyst consisting essentially of one or more amorphous phosphate salts, one or more crystalline phosphate salts, and one or more non-phosphate salts;
• wherein said one or more crystalline phosphate salts and said one or more non-phosphate salts are substantially chemically inert to said one or more amorphous phosphate salts;
• wherein said one or more amorphous phosphate salts consist essentially of:
• i) one or more monovalent cations selected from the group consisting of K+, Rb+, Cs+, and mixtures thereof;
• and
• ii) one or more phosphate anions selected from the group represented by empirical formula (I):
• [H2(1−x)PO(4−x)]− (I);
• wherein x is any real number equal to or greater than 0 and equal to or less than 1;
• wherein said one or more amorphous phosphate salts are neutrally charged;
• or any hydrated form of said one or more amorphous phosphate salts, and mixtures thereof;
• wherein said one or more crystalline phosphate salts consist essentially of:
• i) one or more polyvalent cations, and
• ii) one or more phosphate anions selected from the group represented by molecular formula (II):
• [H(f−2g−h)PfO(4f−g)](2f+h)− (II);
• wherein f is a positive integer;
• wherein g is a positive integer or zero;
• wherein h is an integer;
• wherein (f−2g−h) is equal to or greater than zero;
• wherein (4f−g) is greater than zero;
• wherein (2f+h) is greater than zero;
• wherein (4h/f) is equal to or greater than −2 and equal to or less than 1;
• wherein said one or more crystalline phosphate salts are neutrally charged;
• or any hydrated form of said one or more crystalline phosphate salts, and mixtures thereof;
• wherein said one or more non-phosphate salts consist essentially of:
• i) one or more polyvalent cations, and
• ii) one or more non-phosphate anions selected from the group represented by molecular formulae (III) and (IV):
• [H(a−2b)ScO(4c−b)](2c−a)− (III)
• [Ta2dO(5d+e)]2e− (IV);
• wherein a and b are positive integers or zero;
• wherein c, d, and e are positive integers;
• wherein (a−2b) is equal to or greater than zero;
• wherein (2c−a) is greater than zero;
• wherein said one or more non-phosphate salts are neutrally charged;
• or any hydrated form of said one or more non-phosphate salts, and mixtures thereof;
• wherein the water partial pressure during said contacting step in said gas mixture is equal to or greater than about 0.8 bar;
• wherein said contacting step is performed at a temperature equal to or greater than about 250° C.;
• and
• whereby said acrylic acid, acrylic acid derivatives, or mixtures thereof is produced as a result of said water vapor and said hydroxypropionic acid, hydroxypropionic acid derivatives, or mixtures thereof being contacted with said dehydration catalyst.