A method of making acrylic acid, acrylic acid derivatives, or mixtures thereof comprising contacting a stream comprising lactic acid, lactic acid derivatives, or mixtures thereof with a catalyst comprising: phosphate anions described by formulae (Ic) and (IIc): [H (1-β) P (1+ β) O (4+3β)] 2(1+β)- (Ic), H 2 − 2 γ PO 4 − γ 1 + n − 1 γ 1 + n − 1 γ − (Ic), and at least two different cations, wherein the catalyst is neutrally charged, wherein β and γ are greater or equal to 0 and less or equal to 1, wherein n is at least 2, wherein the molar ratio of said phosphate anions in said catalyst is between about 0.1 and about 10, wherein said at least two different cations comprise at least one monovalent cation and at least one polyvalent cation, and wherein said polyvalent cation is selected from the group consisting of the cations of the metals Be, Mg, Ca, Sr, Ba, Sc, Y, Ti, Zr, V, Nb, Cr, Mo, Mn, Ga, Si, Ge, B, Al, In, Tl, Sb, Sn, Bi, Pb, La, Ce, Er, Ac, Th, and mixtures thereof, wherein said stream further comprises: a. diluent, wherein said diluent is water; and b. gas selected from the group consisting of air, nitrogen helium, argon, carbon dioxide, carbon monoxide, steam, and mixtures thereof and, wherein the water partial pressure in said stream is 50 psi (3.5 bar) or more. phosphate anions described by formulae (Ic) and (IIc): [H (1-β) P (1+ β) O (4+3β)] 2(1+β)- (Ic), H 2 − 2 γ PO 4 − γ 1 + n − 1 γ 1 + n − 1 γ − (Ic), and at least two different cations, wherein the catalyst is neutrally charged, wherein β and γ are greater or equal to 0 and less or equal to 1, wherein n is at least 2, wherein the molar ratio of said phosphate anions in said catalyst is between about 0.1 and about 10, wherein said at least two different cations comprise at least one monovalent cation and at least one polyvalent cation, and wherein said polyvalent cation is selected from the group consisting of the cations of the metals Be, Mg, Ca, Sr, Ba, Sc, Y, Ti, Zr, V, Nb, Cr, Mo, Mn, Ga, Si, Ge, B, Al, In, Tl, Sb, Sn, Bi, Pb, La, Ce, Er, Ac, Th, and mixtures thereof, wherein said stream further comprises: a. diluent, wherein said diluent is water; and b. gas selected from the group consisting of air, nitrogen helium, argon, carbon dioxide, carbon monoxide, steam, and mixtures thereof and, wherein the water partial pressure in said stream is 50 psi (3.5 bar) or more. wherein the catalyst is neutrally charged, wherein β and γ are greater or equal to 0 and less or equal to 1, wherein n is at least 2, wherein the molar ratio of said phosphate anions in said catalyst is between about 0.1 and about 10, wherein said at least two different cations comprise at least one monovalent cation and at least one polyvalent cation, and wherein said polyvalent cation is selected from the group consisting of the cations of the metals Be, Mg, Ca, Sr, Ba, Sc, Y, Ti, Zr, V, Nb, Cr, Mo, Mn, Ga, Si, Ge, B, Al, In, Tl, Sb, Sn, Bi, Pb, La, Ce, Er, Ac, Th, and mixtures thereof, wherein said stream further comprises: a. diluent, wherein said diluent is water; and b. gas selected from the group consisting of air, nitrogen helium, argon, carbon dioxide, a. diluent, wherein said diluent is water; and b. gas selected from the group consisting of air, nitrogen helium, argon, carbon dioxide, carbon monoxide, steam, and mixtures thereof and, wherein the water partial pressure in said stream is 50 psi (3.5 bar) or more.