517results about "Hydrogen fluoride" patented technology

A method for preparing 2,3,3,3-tetrafluoroprop-1-ene comprising (a) providing a starting composition comprising at least one compound having a structure selected from Formulae I, II and III:

CX₂═CCl—CH₂X  (Formula I)

CX₃—CCl═CH₂  (Formula II)

CX₃—CHCl—CH₂X  (Formula III)

• • wherein X is independently selected from F, Cl, Br, and I, provided that at least one X is not fluorine;

(b) contacting said starting composition with a first fluorinating agent to produce a first intermediate composition comprising 2-chloro-3,3,3-trifluoropropene and a first chlorine-containing byproduct; (c) contacting said first intermediate composition with a second fluorinating agent to produce a second intermediate composition comprising 2-chloro-1,1,1,2-tetrafluoropropane and a second chlorine-containing byproduct; and (d) catalytically dehydrochlorinating at least a portion of said 2-chloro-1,1,1,2-tetrafluoropropane to produce a reaction product comprising 2,3,3,3-tetrafluoroprop-1-ene.

Disclosed herein are processes for the production of hydrofluoroolefins by dehydrofluorination. Also disclosed herein are processes for separation of hydrofluoroolefins from hydrofluorocarbons and from hydrogen fluoride.

Disclosed herein are azeotrope or near-azeotrope compositions comprising 2,3,3,3-tetrafluoropropene (HFC-1234yf) and hydrogen fluoride (HF). These compositions are useful in processes to produce and purify HFC-1234yf. Additionally, disclosed herein are processes for the manufacture of HFC-1234yf.

1,1,3,3,3-Pentafluoropropene (CF₃CH═CF₂, HFC-1225zc) can be produced by pyrolyzing 1,1,1,3,3,3-hexafluoropropane (CF₃CH₂CF₃, HFC-236fa) in the absence of dehydrofluorination catalyst at temperatures of from about 700° C. to about 1000° C. and total pressures of about atmosphere pressure in an empty, tubular reactor, the interior surfaces of which comprise materials of construction resistant to hydrogen fluoride.

An integrated process for the manufacture of HFO trans-1,3,3,3-tetrafluoropropene (HFO trans-1234ze) by first catalytically dehydrofluorinating 1,1,1,3,3-pentafluoropropane to thereby produce a mixture of cis-1,3,3,3-tetrafluoropropene, trans-1,3,3,3-tetrafluoropropene and hydrogen fluoride. Then optionally recovering hydrogen fluoride, catalytically isomerizing cis-1234ze into trans-1234ze, and recovering trans-1,3,3,3-tetrafluoropropene.

According to the first characteristic of the present invention, there is provided a production process for 1,3,3,3-tetrafluoropropene including: the first step of reacting 1,1,1,3,3-pentachloropropane with hydrogen fluoride thereby obtaining 1-chloro-3,3,3-trifluoropropene; and the second step of reacting 1-chloro-3,3,3-trifluoropropene obtained in the first step with hydrogen fluoride in a gaseous phase in the presence of a fluorination catalyst. According to the second characteristic of the present invention, there is provided a dehydration process including bringing 1,3,3,3-tetrafluoropropene containing at least water into contact with zeolite.

This invention provides a method for purifying HFO-1234yf by removing HF from a mixture of HFO-1234yf and HF under simple and economically advantageous conditions. According to the present invention, this is a purification method for 2,3,3,3-tetrafluoropropene, (1) the purification method comprising the step of subjecting a mixture comprising 2,3,3,3-tetrafluoropropene and hydrogen fluoride to extractive distillation in a distillation column A using an extractant, thereby obtaining a fraction I that contains 2,3,3,3-tetrafluoropropene and has a lower ratio of hydrogen fluoride to 2,3,3,3-tetrafluoropropene than that of the mixture, while obtaining a fraction II that contains hydrogen fluoride and has a lower ratio of 2,3,3,3-tetrafluoropropene to hydrogen fluoride than that of the mixture; (2) the extractant comprising at least one member selected from the group consisting of: (i) alcohols represented by ROH, wherein R is a C_1-5 alkyl group, (ii) ethers represented by ROR′, wherein R and R′ are the same or different, and each is a C_1-4 alkyl group, (iii) fluorinated alcohols represented by RfOH, wherein Rf is a C_1-3 fluoroalkyl group, (iv) ketones represented by RCOR′, wherein R and R′ are the same or different, and each is a C_1-4 alkyl group, (v) esters represented by RCOOR′, wherein R and R′ are the same or different, and each is a C_1-4 alkyl group, (vi) polyols represented by R(OH)n, wherein R is a C_1-4 alkyl group, and n is an integer of 2 to 3, and (vii) ethylene glycols represented by R¹O(CH₂CH₂O)_nR², wherein R¹ and R² are the same or different, and each is hydrogen or a C_1-4 alkyl group, and n is an integer of 1 to 3.

The present invention pertains to azeotropic and azeotrope-like compositions of the following three blends:

• • 1. Trans-1,3,3,3-tetrafluoropropene (HFO-1234ze(E)), cis-1,3,3,3-tetrafluoropropene (HFO-1234ze(Z)) and hydrogen fluoride (HF);
  • 2. HFO-1234ze(E), 1,1,1,3,3-pentafluoropropane (HFC-245fa) and HF; and
  • 3. HFO-1234ze(Z), HFC-245fa and HF.

These azeotropic and azeotrope-like compositions are useful as intermediates in the production of HFO-1234ze(E).

Provided is a novel method and system for preparing ultra-high-purity buffered-hydrofluoric acid or ammonium fluoride controlled concentration. The method comprises bubbling purified ammonia vapor into ultra-pure hydrofluoric acid. The inventive method and system can be used as an on-site subsystem in a semiconductor device fabrication facility for supplying the buffered-hydrofluoric acid and ammonium fluoride to points of use in the semiconductor device fabrication facility.

Provided are a novel system and method for delivery of a vapor phase product to a point of use, as well as a novel on-site chemical distribution system and method. The system for delivery of a vapor phase product includes a storage vessel containing a liquid chemical under its own vapor pressure, a column connected to receive the chemical in liquified state from the storage vessel, wherein the chemical is fractionated into a contaminated liquid heavy fraction and a purified light vapor fraction and a conduit connected to the column for removing the purified light vapor fraction therefrom. The system is connected to the point of use for introducing the purified vapor fraction thereto. Particular applicability is found in semiconductor manufacturing in the delivery of electronic specialty gases to one or more semiconductor processing tools.

An improved radiation shielding material and storage systems for radioactive materials incorporating the same. The PYRolytic Uranium Compound (“PYRUC”) shielding material is preferably formed by heat and/or pressure treatment of a precursor material comprising microspheres of a uranium compound, such as uranium dioxide or uranium carbide, and a suitable binder. The PYRUC shielding material provides improved radiation shielding, thermal characteristic, cost and ease of use in comparison with other shielding materials. The shielding material can be used to form containment systems, container vessels, shielding structures, and containment storage areas, all of which can be used to house radioactive waste. The preferred shielding system is in the form of a container for storage, transportation, and disposal of radioactive waste. In addition, improved methods for preparing uranium dioxide and uranium carbide microspheres for use in the radiation shielding materials are also provided.

Production of trans-1,3,3,3-tetrafluoropropene by reacting 1-chloro-3,3,3-trifluoropropene with hydrogen fluoride to obtain a reaction product A containing formed trans-1,3,3,3-tetrafluoropropene, unreacted 1-chloro-3,3,3-trifloropropene and hydrogen fluoride, and by-product cis-1,3,3,3-tetrafluoropropene, 1,1,1,3,3-pentafluoropropane and hydrogen chloride; distilling reaction product A to recover a distillation bottom product containing 1-chloro-3,3,3-trifloropropene and hydrogen fluoride and supplying recovered distillation bottom product to the reacting step; recovering hydrogen fluoride from a residue B remaining after recovery of the distillation bottom product and supplying recovered hydrogen fluoride to the reacting step; contacting a residue C remaining after recovery of hydrogen fluoride with water or aqueous sodium hydroxide solution to separate hydrogen chloride; dehydrating a residue D remaining after separation of hydrogen chloride; and distilling a residue E remaining after the dehydration to obtain trans-1,3,3,3-tetrafluoropropene. The method reuses unreacted reactants and produces the target compound efficiently.