bài giảng công nghệ tổng hợp hữu cơ và hóa dầu ethylbenzene nitrobenzene

Fresh benzene is combined with recycle benzene and fed to the alkylation reactor 1.. The combined benzene feedflows in series through the beds, while fresh ethylene feed isdistributed be

TOLUENE, XYLENE

Phenol Cumene

O Maleic anhydride

Unsaturated polyesters Alkyd resins

Tỷ lệ benzene / olefin lớn giúp tăng độ chọn lọcmonoalkylbenzene.

ỨNG DỤNG

- Nguyên liệu chính để sản xuất styrene

- Dung môi trong ngành công nghiệp sơn (< 1%)

- Tổng hợp acetophenone, diethylbenzene,ethylanthraquinone

Acetophenone

- H2

H2C HC

O

CH3+

ETYLATION OF BENZENE

• Xúc tác:

- Huyền phù hoặc trong pha phân tán AlCl3-HCl

- Xúc tác acid rắn trên chất mang Al2O3-SiO2,

- H+

- Sản phẩm phụ: di-, tri-, polyethylbenzenes

- Khắc phục: tăng tỷ lệ mol C6H6 / C2H4 và tuần hoànpolyethylbenzene

XÚC TÁC AlCl3Điều kiện tối ưu: C6H6 / C2H4 = 2 ÷ 2.5

- 41-43 % ethylbenzene (bp 136 o C)

- 38-40 % benzene (bp 80.1 o C)

- 12-14 % diethylbenzene (bp 183-184 o C)

- 2-3 % triethylbenzenes (1,2,4-tri-ethylbenzene 218 o C; 1,3,5-tri-ethylbenzene 216 o C)

- 1.5-2 % polyethylbenzene (bp 185-190 o C)

- 1.5-2 % chlorinated organic compounds (C6H5Cl bp

132oC,…)

• Làm khô benzene (nước < 30 ppm): chưng đẳng phí /chưng dị đẳng phí (min 15 đĩa) / sàng rây phân tử.

- Chuyển nhóm alkyl của polyethylbenzene có thể diễn

ra trong cùng tháp p/u hoặc ở tháp khác (100oC)

CÔNG NGHỆ VỚI XÚC TÁC AlCl3

• Xử lý alkylates:

- Xả áp và làm lạnh xuống 35-40oC  tách lớp

- Phần nặng chứa xúc tác (ts >) quay về thiết bị p/u

- Phần nhẹ chứa 1 phần xúc tác hòa tan xử lý bằngnước, kiềm hoặc NH3 (tách các hợp chất clo)

• Chưng cất trong dãy 3 tháp để tách

- Benzene (chỉ số hồi lưu = 1)

- Ethylbenzene (chỉ số hồi lưu = 1.5)

- Polyethylbenzene

35-40 o C

100 o C (đỉnh), 210-215 o C (đáy), 6.5-13 kPa

C 6 H 6 , HCl

~ 150 o C, 0.5-1 MPa

100 o C

XÚC TÁC RẮN

Có thể sử dụng xúc tác: zeolit, BF3/Al2O3, SiO2/Al2O3

CÔNG NGHỆ ALKAR UOP1958:

- 8-10 % vol C2H4

- Benzene khan (H2O 2-3 ppm)

- BF3/ Al2O3 hạn chế sự ăn mòn vì không hình thànhdạng acid chứa proton

- Xúc tác này không hỗ trợ quá trình alkyl hóa vàchuyển nhóm alkyl đồng thời

- Độ chuyển hóa 1 lần 25-30%

CÔNG NGHỆ ALKAR UOP

(BOF) 3 , C 6 H 6 <<

Zeolit được xem là xúc tác thích hợp cho p/ualkylation hơn các aluminosilicate vô định hình vì

- Hoạt tính cao hơn

- Độ chọn lọc lớn hơn

- Độ acid cân bằng tốt hơn

Lummus Technology and UOP LLC

Benzene and ethylene are reacted over a proprietaryzeolite catalyst in a fixed-bed, liquid-phase reactor

Fresh benzene is combined with recycle benzene and fed

to the alkylation reactor (1) The combined benzene feedflows in series through the beds, while fresh ethylene feed isdistributed between the beds The reaction is highlyexothermic, and heat is removed between the reaction stages

by generating steam Unreacted benzene is recovered from theoverhead of the benzene column (3), and EB product is taken

as overhead from the EB column (4)

A small amount of polyethylbenzene (PEB) is recovered

in the overhead of the PEB column (5) and recycled back tothe transalkylation reactor (2) where it is combined withbenzene over a proprietary zeolite catalyst to produceadditional EB product A small amount of flux oil isrecovered from the bottom of the PEB column (5) and isusually burned as fuel

The catalysts are non-corrosive and operate at mildconditions, allowing for all carbon-steel construction.The reactors can be designed for 2–7 year catalyst cyclelength, and the catalyst is fully regenerable The processdoes not produce any hazardous effluent.

Yields and product quality:

Ethylbenzene has high purity (99.9 %wt minimum) and

is suitable for styrene-unit feed

Xylene make is less than 10 ppm

The process has an overall yield of 99.7%

Lummus Technology and UOP LLC

Ethylene reacts with benzene in either a totally liquid-filed or mixed-phase alkylation reactor (1) containing multiple fixed-beds of ExxonMobil’s proprietary catalyst, forming EB and very small quantities of polyethylbenzenes.

In the transalkylation reactor (2), polyethylbenzenes are converted to EB by reaction with benzene over ExxonMobil’s transalkylation catalyst.

Effluents from the alkylation and transalkylation reactors are fed

to the benzene column (3), where unreacted benzene is recovered from crude EB.

The fresh benzene feedstock and a small vent stream from the benzene column are fed to the lights column (4) to reject light impurities The lights column bottoms is returned to the benzene column.

The bottoms from the benzene column is fed to the EB column (5)

to recover EB product.

The bottoms from the EB column is fed to the PEB column (6) where polyethylbenzenes are recovered as a distillate, and heavy compounds are rejected in a bottoms stream that can be used as fuel.

Cycle lengths in excess of four years are expected for the alkylation and transalkylation catalysts.

Process equipment is fabricated entirely from carbon steel.

Capital investment is reduced as a consequence of the high activity and extraordinary selectivity of the alkylation catalyst and the ability of both the alkylation and transalkylation catalysts to operate with very low quantities of excess benzene Product quality:

The EB product contains less than 100 ppm of C8 plus C9 impurities.

Product purities of 99.95% to 99.99% are expected.

Badger licensing LLC.

alkylation catalyst packaged in a proprietary CD structure.

The process is able to handle a wide range in ethylene feed composition—from 10% to 100% ethylene This is the only technology that can handle a very dilute ethylene feedstock while producing high- purity EB.

The CD alkylator stripper (1) operates as a distillation column Alkylation and distillation occur in the alkylator in the presence of a zeolite catalyst packaged in patented structured packing.

Unreacted ethylene and benzene vapor from the alkylator top are condensed and fed to the fiishing reactor (2) where the remaining ethylene reacts over zeolite catlayst pellets.

The alkylator stripper bottoms is fractionated (4, 5) into EB product, polyethylbenzenes and flux oil.

The polyethylbenzenes are transalkylated with benzene over zeolite catalyst pellets in the transalkylator (3) to produce additional EB.

The ethylene can be polymer grade or, with only minor differences in the process scheme, dilute ethylene containing as little as 10 mol.% ethylene

Yields and product quality:

Both the alkylation and trans-alkylation reactions arehighly selective-producing few byproducts

The EB product has high purity (99.9 wt% minimum)and is suitable for styrene-unit feed Xylene make is lessthan 10 ppm The process has an overall yield of 99.7%

and Chemical Research & Licensing

NITROBENZENE

ỨNG DỤNG

- Nguyên liệu để tổng hợp aniline (95 %)

- Dung môi

TÍNH CHẤT VẬT LÝ

- Chất lỏng màu vàng nhạt, mùi hạnh nhân đắng

- Hòa tan trong hầu hết các dung môi hữu cơ

- Trộn với benzene ở bất cứ tỷ lệ nào

- Độ tan với nước 0.19 g / 100 ml H2O (20oC)

- Nhiệt độ sôi 210.9oC / 760 mmHg

- Nhiệt độ đông đặc 5.7oC / 760 mmHg

reduction electrolytic

H

2 / ca taly st

Methylene diphenylene isocyanate

Diphenylamine

n-Alkylanilines

Sulfanilic acid Hydroquinone

HNO3 + 2 H2SO4 2 HSO4- + H3O+ + NO2+

NO2

Nitrator 50-100 o C Separator

Wash Separator

Still

Acid concentrator Water

Mixed acid (Simultaneous feed with

slight excess of benzene)

C 6 H 6 (recycle)

Spent acid

In this process, the initial benzene is first introducedinto an extractor where it is placed in contact with the acidresidue resulting from the subsequent nitration, in order toabsorb the residual nitrobenzene content.

The mixture formed is settled in a Biazzi separator

- The upper organic phase, representing the extract, is sent

to the reaction system

- The lower acid layer, consisting essentially of dilutesulfuric acid (68 % wt.) is re-concentrated byevaporation (95 % wt.) and then recycled

Nitration is carried out in a series of agitated reactors, quipped with internal cooling coils, where the temperature is kept at about 60oC by means of cold water circulation The feed consists of a mixture of sulfuric (95 %wt.) and nitric (65 %wt.) acids and the organic phase from the Biazzi separator A similar system is also employed to treat the reactor effluents and to settle a bottom acid phase, directly recycled to the initial extractor, and an upper organic phase rich in nitrobenzene.

The purification of this crude product comprises neutralization by caustic soda (50 %wt.), followed by water washings conducted in a succession of mixers alternating with Biazzi separators.

Systematic recycling of the aqueous phases recovered to the previous stage ensures a pseudo- countercurrent with helps to remove the inorganic and organic acids (picric acid: 2,4,6-trinitrophenol

nitrophenols The solution isolated at the end, in other words at the top the neutralizer, is stripped by steam to recover its residual nitrobenzene content, and then eliminated The organic layer from the final Biazzi separator is rid of the benzene it contains, also by stripping.

H 2 SO 4 (95 % wt.)

C 6 H 6

NaOH (50 % wt.)