Phosphonate salts are the result of deprotonation of phosphonic acids, which are diprotic acids: Phosphonate esters are the result of condensation of phosphonic acids with alcohols. Several methods exist for the preparation of phosphonic acids and their salts.
1 Stir in the tomato sauce, tomato paste, vinegar, diced tomatoes, and brown sugar. Season with chili powder, Italian seasoning, and salt. Bring to a boil, reduce heat to low, and simmer 1 hour.  Mix the cornstarch and water, and stir into the salsa to thicken. Transfer salsa to sterilized jars, leaving 1/2 inch headroom, and seal. Process jars in a boiling water bath 15 minutes. Store unsealed jars in the refrigerator.
I found this to be a very effective (and less messy) method for making my tomatoes the proper consistency. Mix your diced ingredients into the tomatoes. Add the vinegar, salt, hot sauce mix and 1/8 cup of sugar if you desire a sweeter salsa. Bring your salsa to a boil then keep it at a consistent simmer for 35 minutes. For a thicker salsa, and especially if you have really juicy tomatoes, simmer 5 or 10 minutes longer. After the mixture cools completely, divide it among quart freezer bags or freezer containers and keep frozen for up to a year. If you use bags, try flattening and freezing them separately before stacking them together.