摘要:
The present invention is directed to a method for the production of D,L-aspartic acid. The method comprises reacting an unsaturated dicarboxylic acid or anhydride, such as, maleic acid, fumaric acid, maleic anhydride, or mixtures thereof, with excess aqueous ammonia at an elevated temperature and pressure for a time sufficient to produce diammonium D,L-aspartate. The produced diammonium D,L-aspartate is then neutralized to D,L-aspartic acid. Excess unreacted ammonia and various by-products may be recycled and re-used in the method, thereby minimizing waste and reducing cost. The produced D,L-aspartic acid may be subsequently used to make polyaspartic acid.
摘要:
The present invention is directed to a method for the production of D,L-aspartic acid. The method comprises reacting an unsaturated dicarboxylic acid or anhydride, such as, maleic acid, fumaric acid, maleic anhydride, or mixtures thereof, with excess aqueous ammonia at an elevated temperature and pressure for a time sufficient to produce diammonium D,L-aspartate. The produced diammonium D,L-aspartate is then neutralized to D,L-aspartic acid. Excess unreacted ammonia and various by-products may be recycled and re-used in the method, thereby minimizing waste and reducing cost. The produced D,L-aspartic acid may be subsequently used to make polyaspartic acid.
摘要:
A method for the preparation of a succinimide copolymer by the catalytic co-polymerization of aspartic acid with a selected polyfunctional monomer in the presence of a cyclic carbonate solvent. Succinimide copolymers of relatively high weight average molecular weight and high purity can be produced in relatively high yields while employing a relatively low catalyst loading.
摘要:
A method for the preparation of a succinimide copolymer by the catalytic co-polymerization of aspartic acid with a selected polyfunctional monomer in the presence of a cyclic carbonate solvent. Succinimide copolymers of relatively high weight average molecular weight and high purity can be produced in relatively high yields while employing a relatively low catalyst loading.
摘要:
A method for the preparation of a desired molecular weight polysuccinimide by the catalytic polymerization of aspartic acid in the presence of a thioether solvent. Polysuccinimide of relatively high weight average molecular weight and high purity can be produced in relatively high yields while employing a relatively low catalyst loading and relatively low temperatures.
摘要:
A method for the preparation of a succinimide copolymer by the catalytic co-polymerization of aspartic acid with a selected polyfunctional monomer in the presence of a cyclic carbonate solvent. Succinimide copolymers of relatively high weight average molecular weight and high purity can be produced in relatively high yields while employing a relatively low catalyst loading.
摘要:
Ultrasonic techniques are applied to the measurement of wooden members to identify splits in wooden members. Multiple angularly displaced measurements allow detection of splits at arbitrary angles.
摘要:
Ultrasonic techniques are applied to the measurement of wooden members to identify localized anomalies internal to the wooden members substantially smaller than the full width of the ultrasonic beam. Multiple spatially displaced measurements allow generation of comprehensive maps of the wooden members to aid in computer cutting and grading of the wooden members.
摘要:
Polysuccinimide is prepared by reacting ammonia gas with liquid maleic anhydride. The reaction is initially carried out at a temperature which is above the melting point of the maleic anhydride but below the boiling point of liquid maleic anhydride for a time period sufficient for the liquid maleic anhydride to react with the ammonia gas to form a reaction product thereof. The reaction product is subsequently polymerized to polysuccinimide. The present method avoids the prior art problems of water removal and minimizes the need for ammonia handling equipment. The polysuccinimide product can be readily hydrolyzed to polyaspartic acid or a salt thereof, if desired.
摘要:
Ultrasonic techniques are applied to the measurement of wooden members to detect splitting during sawing operations and thereby allow modification of a sawing technique or change in saw cut placement.