We are the leading and trusted importers, suppliers and distributors of a wide range and high variety of acrylamide. It widely finds application as flocculant, water treatment chemicals, textile sizing agent and paper chemicals.

Field of the invention

this invention relates to corrosion inhibition and, in particular, to corrosion inhibition by potable waters such as municipal drinking waters and the like.

2. Brief description of the prior art

treatment of water with soluble salts such as alkali metal hexametaphosphates has been practiced for many years. The hexametaphosphate salts were initially employed in threshold treatment of waters such as boiler feed water and the like since it was recognized that the hexametaphosphate was a strong complexing agent for iron and manganese, preventing their precipitation and resultant scale formation on the equipment of steam power plants.

An outgrowth of the threshold treatment of water was the discovery that the hexametaphosphate salts could also be employed to inhibit or prevent corrosion of iron and mild steel surfaces. The exact mechanism of this corrosion prevention is not entirely understood although it is generally believed that the hexametaphosphate forms a protective, passivating film on the metal surfaces. It has long been recognized that the hexametaphosphate must be employed at concentrations of at least about 50 or 60 ppm to achieve passivating of fresh metal surfaces, following which the concentration can be reduced to about 20-30 ppm to maintain the film. Attempts to achieve corrosion prevention with lower concentrations of the hexametaphosphate have not been successful in reducing the overall corrosion rate, although some investigators have reported that hexametaphosphate salts have been observed to reduce the pitting nature of the corrosion when employed in low concentration.

It is desirable to minimize the quantities of phosphate additives in water to lessen the risk of promoting growth of algae and aquatic plants. It is also desirable to minimize the amounts of complex phosphates, such as hexametaphosphate in water to avoid undesirable coagulation proble

Process for lthe production of sodium nitrite filed july 23, 1932 attorney patented mar. 3, 1936 united states patent office process for the production of sodium nitrite york application july 23, 1932, serial no. 624, 200

8 claims.

This invention relates to a process for the production of sodium nitrite by the absorption of nitrogen oxides in alkaline solutions such as solutions of sodium hydroxide or carbonate, and it is an object of this invention to provide a process whereby sodium nitrite of a high degree of purity may be recovered from the solution thus produced, with an economical utilization of the raw materials entering the process and their complete recovery, principally in the :form of sodium nitrite, but also in the form of a mixed nitritenitrate by-product.

One feature of the invention is an improvement in the process for the absorption of nitrogen oxides in a solution of sodium carbonate to form sodium nitrite wherein the nitrogen oxides are passed in series through a plurality of absorption stages in contact with the solution and the solution is cooled to crystallize solid sodium nitrite, which improvement involves separating the crystallized solid sodium nitrite from the mother liquor and mixing the mother liquor with the sodium carbonate solution undergoing treatment with the nitrogen oxides. Another portion of the mother liquor is withdrawn and a mixed solid sodium nitrate-sodium nitrite product is recovered therefrom.

Field of invention
[0001]
this invention relates to processes and intermediates for the stereoselective synthesis of substituted morpholine derivatives, which can serve as nk1 receptor antagonists. In particular, the invention allows the stereoselective preparation of new compounds, which allow an efficient access to aprepitant and fosaprepitant, two potent and orally active nk1 antagonists.

Method for preparing a liquid akd wax
technical field
[0001] the present invention relates to the field of papermaking, and more particularly to a method for preparing a liquid akd wax.
Background technique
[0002] akd wax into solid and liquid. Wherein the liquid alkyl ketene dimer (also known as branched chain alkyl ketene dimer, referred to as liquid akd wax) belong to the sizing categories, it is still in the research stage at home and abroad, much practical application. After the wax is liquid akd sizing development. Liquid wax has a slip coefficient is small, suitable for high speed rotary printing advantages can clean paper systems to reduce pollution emissions, energy conservation has the role of increasing the reaction rate of akd, fast curing, low temperature sizing features.

background of the invention
1. field of the invention
this invention relates to a process for high yield manufacture of high purity melamine and the apparatus to carry out the process.
more particularly this invention is directed to melamine preparation starting from urea using a high pressure process.
2. description of prior art
melamine is presently manufactured from urea according to the following simplified reaction scheme:

Phenol may be produced from cumene by the oxidation of cumene to cumene hydroperoxide, followed by cleavage of the hydroperoxide to phenol and acetone.
In such a process, the reaction product is introduced into a separation and recovery system wherein the crude product is initially treated in a distillation column to separate acetone byproduct from the remaining mixture. The acetone-free product is then introduced into a further distillation column which operates to separate cumene from the remaining product. Optionally, the cumene recovery column can be operated to recover alpha-methylstyrene (ams) with the cumene. If the ams is not recovered with the cumene, the product remaining from the cumene column is introduced into a crude ams column to separate ams from the remaining mixture.

We are the leading and trusted importers, suppliers and distributors of a wide range and high variety of acrylamide. It widely finds application as flocculant, water treatment chemicals, textile sizing agent and paper chemicals.

Field of the invention this invention relates to corrosion inhibition and, in particular, to corrosion inhibition by potable waters such as municipal drinking waters and the like. 2. Brief description of the prior art treatment of water with soluble salts such as alkali metal hexametaphosphates has been practiced for many years. The hexametaphosphate salts were initially employed in threshold treatment of waters such as boiler feed water and the like since it was recognized that the hexametaphosphate was a strong complexing agent for iron and manganese, preventing their precipitation and resultant scale formation on the equipment of steam power plants. An outgrowth of the threshold treatment of water was the discovery that the hexametaphosphate salts could also be employed to inhibit or prevent corrosion of iron and mild steel surfaces. The exact mechanism of this corrosion prevention is not entirely understood although it is generally believed that the hexametaphosphate forms a protective, passivating film on the metal surfaces. It has long been recognized that the hexametaphosphate must be employed at concentrations of at least about 50 or 60 ppm to achieve passivating of fresh metal surfaces, following which the concentration can be reduced to about 20-30 ppm to maintain the film. Attempts to achieve corrosion prevention with lower concentrations of the hexametaphosphate have not been successful in reducing the overall corrosion rate, although some investigators have reported that hexametaphosphate salts have been observed to reduce the pitting nature of the corrosion when employed in low concentration. It is desirable to minimize the quantities of phosphate additives in water to lessen the risk of promoting growth of algae and aquatic plants. It is also desirable to minimize the amounts of complex phosphates, such as hexametaphosphate in water to avoid undesirable coagulation proble

Process for lthe production of sodium nitrite filed july 23, 1932 attorney patented mar. 3, 1936 united states patent office process for the production of sodium nitrite york application july 23, 1932, serial no. 624, 200 8 claims. This invention relates to a process for the production of sodium nitrite by the absorption of nitrogen oxides in alkaline solutions such as solutions of sodium hydroxide or carbonate, and it is an object of this invention to provide a process whereby sodium nitrite of a high degree of purity may be recovered from the solution thus produced, with an economical utilization of the raw materials entering the process and their complete recovery, principally in the :form of sodium nitrite, but also in the form of a mixed nitritenitrate by-product. One feature of the invention is an improvement in the process for the absorption of nitrogen oxides in a solution of sodium carbonate to form sodium nitrite wherein the nitrogen oxides are passed in series through a plurality of absorption stages in contact with the solution and the solution is cooled to crystallize solid sodium nitrite, which improvement involves separating the crystallized solid sodium nitrite from the mother liquor and mixing the mother liquor with the sodium carbonate solution undergoing treatment with the nitrogen oxides. Another portion of the mother liquor is withdrawn and a mixed solid sodium nitrate-sodium nitrite product is recovered therefrom.

Field of invention[0001]this invention relates to processes and intermediates for the stereoselective synthesis of substituted morpholine derivatives, which can serve as nk1 receptor antagonists. In particular, the invention allows the stereoselective preparation of new compounds, which allow an efficient access to aprepitant and fosaprepitant, two potent and orally active nk1 antagonists.

Method for preparing a liquid akd waxtechnical field[0001] the present invention relates to the field of papermaking, and more particularly to a method for preparing a liquid akd wax.Background technique[0002] akd wax into solid and liquid. Wherein the liquid alkyl ketene dimer (also known as branched chain alkyl ketene dimer, referred to as liquid akd wax) belong to the sizing categories, it is still in the research stage at home and abroad, much practical application. After the wax is liquid akd sizing development. Liquid wax has a slip coefficient is small, suitable for high speed rotary printing advantages can clean paper systems to reduce pollution emissions, energy conservation has the role of increasing the reaction rate of akd, fast curing, low temperature sizing features.

background of the invention1. field of the inventionthis invention relates to a process for high yield manufacture of high purity melamine and the apparatus to carry out the process.more particularly this invention is directed to melamine preparation starting from urea using a high pressure process.2. description of prior artmelamine is presently manufactured from urea according to the following simplified reaction scheme:

Phenol may be produced from cumene by the oxidation of cumene to cumene hydroperoxide, followed by cleavage of the hydroperoxide to phenol and acetone.In such a process, the reaction product is introduced into a separation and recovery system wherein the crude product is initially treated in a distillation column to separate acetone byproduct from the remaining mixture. The acetone-free product is then introduced into a further distillation column which operates to separate cumene from the remaining product. Optionally, the cumene recovery column can be operated to recover alpha-methylstyrene (ams) with the cumene. If the ams is not recovered with the cumene, the product remaining from the cumene column is introduced into a crude ams column to separate ams from the remaining mixture.