Abstract:
PURPOSE: A method for distilling a vinyl aromatic monomer is provided, which is suitable for destabilizing and purifying the styrene stabilized with 4-t-butylcatechol for transportation. CONSTITUTION: The method comprises the step of distilling a vinyl aromatic monomer in the presence of 4-t-butylcatechol and oxygen containing no aromatic nitro or amino compound. The vinyl aromatic monomer is preferably styrene. 4-t-Butylcatechol is fed into a distillation apparatus together with a vinyl aromatic monomer, and the concentration of 4-t-butylcatechol is 200-15,000 ppm at the bottom part of the distillation apparatus based on the concentration of the vinyl aromatic monomer. The vacuum distillation is carried out at a temperature of 40-125 deg.C. A gas containing oxygen is fed by a circulation pump equipped at the suction side upstream of a distillation assembly. The content of oxygen fed is 0.01-0.5 wt.% based on the weight of the vinyl aromatic monomer.
Abstract:
본 발명은 A) n-부텐을 함유하는 공급물 기체 유동물(a)을 제공하는 단계; B) n-부텐을 함유하는 공급물 기체 유동물(a) 및 산소-함유 기체를 하나 이상의 탈수소화 영역에 공급하여 n-부텐을 산화성 탈수소화시켜 부타디엔을 형성하여, 부타디엔, 미반응 n-부텐, 수증기, 산소, 저비점 탄화수소, 임의로 탄소 산화물 및 임의로 불활성 기체를 함유하는 생성물 기체 유동물(b)을 수득하는 단계; C) 생성물 기체 유동물(b)을 냉각시키고, 적어도 압축 단계에서 압축시켜, 물을 함유하는 하나 이상의 응축물 유동물(c1) 및 부타디엔, n-부텐, 수증기, 산소, 저비점 탄화수소, 임의로 탄소 산화물 및 임의로 불활성 기체를 함유하는 기체 유동물(c2)을 수득하는 단계; D) Da) 부타디엔 및 n-부텐을 함유하는 C4-탄화수소를 고온에서 비등하는 흡수 수단에 흡수시켜, C4-탄화수소가 충전된 흡수제 유동물 및 기체 유동물(d2)을 수득하고, Db) 불활성 기체를 사용한 탈거에 의해, C4-탄화수소가 충전된 흡수제 유동물로부터 산소를 제거하고, Dc) 충전된 흡수제 유동물로부터 C 4 탄화수소를 탈착시켜, 100 ppm 미만의 산소를 갖는, 본질적으로 C 4 -탄화수소로 이루어진 C 4 -생성물 기체 유동물(d1)을 수득함으로써, 산소, 저비점 탄화수소, 임의로 탄소 산화물 및 임의로 불활성 기체를 함유하는 응축불가능한 저비점 기체 성분 부분을 기체 유동물(c2)로부터 분리하는 단계; E) 부타디엔에 대해 선택적인 용매를 사용하는 추출 증류를 통해, C4-생성물 유동물(d1)을, 부타디엔 및 선택적 용매를 함유하는 물질 유동물(e1) 및 n-부텐을 함유하는 물질 유동물(e2)로 분리하는 단계; F) 부타디엔 및 선택적 용매를 함유하는 물질 유동물(e1)을 증류시켜 본질적으로 선택적 용매로 이루어진 물질 유동물(f1) 및 부타디엔을 함유하는 물질 유동물(f2)을 수득하는 단계를 포함하는 것인, n-부텐으로부터 부타디엔을 제조하는 방법에 관한 것이다.
Abstract:
고온 공정 또는 증류 공정 동안 비닐 방향족 단량체, 예컨대 스티렌 단량체의 중합을 억제하는 방법 및 조성물을 제공한다. 조성물은 (A) 하이드록시아민 및 (B) 안정한 자유 라디칼을 포함하는 억제제 혼합물 및 (C) 다이니트로부틸페놀 또는 (D) 퀴논 메타이드인 지연제를 포함한다. (A) : (B)의 비는 약 5 % (A) : 95 % (B) 내지 약 95 % (A) : 약 5 % (B)이다. 조성물은 증류 공정 동안 중합 억제에 충분한 양으로 비닐 방향족 단량체에 첨가된다. 일반적으로 억제제 혼합물은 비닐 방향족 단량체에 상기 단량체의 약 10 ppm 내지 150 ppm의 양으로 첨가된다. 일반적으로 지연제는 비닐 방향족 단량체의 50 ppm 내지 1500 ppm의 양으로 비닐 방향족 단량체에 첨가된다.
Abstract:
The invention relates to a process for preparing butadiene from n-butenes, comprising the steps of: A) providing an input gas stream (a) comprising n-butenes, B) feeding the input gas stream (a) comprising n-butenes and a gas containing at least oxygen into at least one oxidative dehydrogenation zone and oxidatively dehydrogenating n-butenes to butadiene, wherein a product gas stream (b) comprising butadiene, unconverted n-butenes, water vapour, oxygen, low-boiling hydrocarbons and high-boiling secondary components, optionally carbon oxides and optionally inert gases is obtained; Ca) cooling the product gas stream (b) by bringing into contact with a cooling medium in at least one cooling zone, the cooling medium being at least partly recycled and having an aqueous phase and an organic phase ; Cb) compressing the cooled product gas stream (b) which may have been depleted of high-boiling secondary components in at least one compression stage, giving at least one aqueous condensate stream (c1) and one gas stream (c2) comprising butadiene, n-butenes, water vapour, oxygen and low-boiling hydrocarbons, optionally carbon oxides and optionally inert gases; D) removing uncondensable and low-boiling gas constituents comprising oxygen and low-boiling hydrocarbons, with or without carbon oxides and with or without inert gases, as gas stream (d2) from the gas stream (c2) by absorbing the C 4 hydrocarbons comprising butadiene and n-butenes in an absorbent, giving an absorbent stream laden with C 4 hydrocarbons and the gas stream (d2), and then desorbing the C 4 hydrocarbons from the laden absorbent stream, giving a C 4 product gas stream (d1), E) separating the C 4 product stream (d1) by extractive distillation with a butadiene-selective solvent into a stream (e1) comprising butadiene and the selective solvent and a stream (e2) comprising n-butenes; F) distilling the stream (e1) comprising butadiene and the selective solvent into a stream (f1) consisting essentially of the selective solvent and a stream (f2) comprising butadiene, charactersied in that step Cb) comprises at least two compression stages Cba) and at least two cooling stages Cbb), which are designed as quench columns, in the cooling stage, the cooling takes place by bringing into direct contact with the two phase cooling medium having an aqueous and an organic phase.
Abstract:
Disclosed are a method of preparing conjugated diene and a device therefor. More particularly, disclosed a method of preparing conjugated diene, wherein generated gas including butadiene is cooled and then water discharged at a lower part is not directly treated as waste water and subjected to byproduct removal and steam-extraction to utilize converted steam, and an installation issue of an existing biological waste water disposal equipment due to an excessive amount of byproducts can be resolved, and a device therefor are disclosed.
Abstract:
A process for separating and purifying a conjugated diene which comprises a step of distilling a hydrocarbon mixture containing 80 % or more of a conjugated diene in a low boiling fraction distillation column (14) in the presence of a polymerization inhibitor, to give a first bottom fraction, a step of distilling the first bottom fraction in a high boiling fraction distillation column (16) in the presence of a polymerization inhibitor, to give a second bottom fraction and a distillate fraction, a step of measuring the concentrations of a polymerization inhibitor contained in the first and second bottom fractions, a first control step of adding a polymerization inhibitor to the low boiling fraction distillation column (14) and/or the high boiling fraction distillation column (16) in amounts adjusted depending on the respective concentrations of a polymerization inhibitor contained in the first and second bottom fractions, to thereby control the concentrations of the polymerization inhibitor contained in the first and second bottom fractions, a step of measuring the concentration of a polymerization inhibitor contained in the distillate fraction, and a second control step of adding a polymerization inhibitor to the high boiling fraction distillation column (16) in an amount adjusted depending on the concentration of a polymerization inhibitor contained in the distillate fraction, to thereby control the concentration of a polymerization inhibitor contained in the distillate fraction. The process allows the suppression of generation of a popcorn polymer with good efficiency and with stability.
Abstract:
An improvement in a Ryan/Holmes separation of methane from carbon dioxide is disclosed wherein the upper portion of a distillation column is operated at temperatures above the triple point of carbon dioxide, i.e., -70 DEG F., while still effectuating a separation of methane from carbon dioxide. This is achieved by increasing the amount of non-polar liquid agent added to the condenser of the column to an amount sufficient to maintain the condenser and all portions of the column at such temperatures.