Petrochemical Processes

Purified Terephthalic Acid (PTA)

Vahidreza Bitarafhaghighi

Dr. Lashani Zadegan

Outline• Introduction• Questions• History• Physical and Chemical Properties• Main Applications• Production Process

• Production Methods• Reaction• Schematic of process• P&ID

• Iran Manufacturers• Economic Analysis

Introduction

Terephthalic acid is an organic substance with the chemical formula C6H4 (COOH) 2. This colorless solid material is used as a commodity chemical to produce polyester PolyEthylene Terephthalate (PET) fibers. PET is used to produce plastic bottles and fibers.

Terephthalic acid was made in 1836 by the French chemist Auguste by oxidizing naphthalene tetrachloride on the assumption that the resulting material is one of the derivatives of naphthalene. He then called it acid Naftanilic .

Jean Charles Galissard de Marignac, Swiss chemist, determined its formula and showed that Laurent assumption in determination of the name is incorrect. He called this substance terephthalic acid.

History

Physical and Chemical Properties

Only trace amounts of Terephthalic acid is soluble in water and alcohol therefore, until 1970, it was turned to dimethyl ester 1970

for purification purposes.

Chemical Formula C8H6O4

Molecular Weight 166.13 g/mol

Appearance white crystals or powder

Density 1.522 g/cm³

Main Applications

• Raw material and feed in PolyEthylene Terephtalate(PET) production

• Base reagent in wool spinning factories• Additive in animal feed preparation• As a lubricant in the preparation of industrial

adhesives• The main consumption of terephthalic acid is

in production of saturated linear polyester resins used in production of bottles, thin films and polyethylene terephtalate (PET) fibers.

Production Process

Terephthalic acid is produced by oxidation of Paraxylene in the presence of oxygen in the air

Oxidation is done with acetic acid as the solvent and the catalyst consists of cobalt and manganese and bromide salts. The most hazardous material in acid impurities is 4-formylbenzoic which will be separated by hydrogenation of a hot aqueous solution. Then the solution is cooled in a stage wise manner until the crystals of pure terephthalic acid

are separated .Another method of PTA production is called Henkel process, or Raecke process, which comes from the company name. This method does not have commercial-scale application. In this method phthalic acid is turned to terephthalic acid by potassium salts.

Terephthalic acid can also be produced in the laboratory by oxidation of benzene derivatives, such as oil, caraway or a combination of cymene and cuminol with Cromic acid.

PRPDUCTION METHODS:

Reaction

The overall terephthalic acid production reaction is as follows:

The Oxygen supply is air. Typically the catalyst is a combination of cobalt acetate and manganese acetate and a bromine compound

such as sodium bromide and acetic acid as the solvent.The reaction temperature is about 200 ° C

Schematic of The process

تولید فرآیندAcetic acid 90 %Mangenese bromor 2 %Water 4 %

TPA 20 %Water 6 %Acetic acid 69.7 %

6 atm176 c

Inert gasesExcess oxygenCOCO2VOC

Acetic acidMethyle acetatewater

Crude terephtalic acid process

Purification of Crude Terephthalic Acid

Iran manufacturers

Ranked 2 in

Exports

Iran Producers and their share in export 2007

Domestic production Tondgoyan Complex 2008

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Total Phase 1

Total Phase 2

Total

Month up to dateYear up to date

theoryplannedactual%% Average Daily

theoryplannedactual%% Product

Tondgoyan Petrochemical Complex

Tondgoyan Petrochemical Company was established with the approval of the Board of Directors of the National Petrochemical Company for pure terephthalic acid (PTA) and polyethylene terephthalate (PET) production projects in 1998.

PTA / PET first and second projects were constructed in Persian Gulf in the north-western Khuzestan province in Mahshahr Petrochemical Special Economic Zone in the land area of 34 hectares. Purified Terephthalic Acid (PTA) is an important raw material for the production of polyethylene terephthalate resins. The process has been substantial growth in production and consumption in the world.Polyethylene terephthalate (PET) as important raw material in polyesters which are used in the production of artificial fibers and cotton textile, plastic film industry, production of beverage bottles, cans and containers used in the packaging of food, pharmaceutical and health, which is growing increasingly in production and consumption trend.

PTA / PET project has been implemented in two phases. In phase one it was launched, and the second phase was start-up of PTA-2 and pre-commissioning of PET-2 unit.

Economic analysisThe total investment of plan in Tondgoyan Complex is $ 774 million dollars or 2,085 billion rials. The annual product sales rate in theoretical capacity is forecasted to be $ 800 million.

World production in 1970 was about 1.75 million tons per year.

It reached 30 million tons per year in 2006

Iran’s Price

235 $/ton

US Price (2006)

926 $/ton

World production in 1970 was about 1.75 million tons per year.

It reached 30 million tons per year in 2006

Comparison Chart of the theoretical capacity, projection, and production since the beginning of the year 2008

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Theoretical capacity

Projection

Production

Country 2004 2005 2006 2007 2008India 2015 2015 2695 2695 2695Indonesia 1975 1975 1975 1975 1975Japan 1835 1835 1835 1835 1835Malaysia 600 600 600 600 600Pakistan 450 450 450 450 450China 5190 6390 8790 12390 12990South Korea 5620 5620 5730 5730 5730Taiwan 4950 4950 4950 5250 5250Thailand 1350 1850 2650 2650 2650Total Asia 23985 25685 29675 33575 34175

PTA Capacity - Pacific Asian 2008 (Thousand Tons)

India8%

Andonesiaا6%

Japan5%

Malaysia2%

Pakistan1%

China38%

South Korea17%

Taiwan15%

Tailand8%

PTA Capacity - Pacific Asian 2008 (Thousand Tons)

CANADA; 500; 1% MEXICO; 1266; 3%

USA; 4200; 11%

CENTRAL & SOUTH AMER-

ICA; 333; 1%

WESTERN EUROPE; 3683; 10%

CENTRAL & EASTERN

EUROPE; 472; 1%MIDDLE EAST;

874; 2%

JAPAN; 1705; 5%

CHINA; 6756; 18%

OTHER ASIA; 17542; 47%

Numbers are in thousands of tons

Global Production 2008

CANADA; 369; 4% MEXICO; 311; 3%USA; 242; 2%

WESTERN EUROPE; 2075; 20%

CENTRAL & EASTERN

EUROPE; 50; 0%MIDDLE EAST;

391; 4%JAPAN; 553; 5%

OTHER ASIA; 6427; 62%

Global Export 2008

CANADA; 205; 1% MEXICO; 958; 3%

USA; 4323; 12%

CENTRAL & SOUTH AMER-

ICA; 695; 2%

WESTERN EU-ROPE; 3207; 9%

CENTRAL & EASTERN

EUROPE; 678; 2%

MIDDLE EAST; 776; 2%

JAPAN; 1192; 3%

CHINA; 14048; 38%

OTHER ASIA; 11115; 30%

Global Import 2008

CANADA; 74; 1%MEXICO; 3; 0% USA; 365; 4%

CENTRAL & SOUTH AMERICA; 362; 4%

WESTERN EU-ROPE; 1599; 16% CENTRAL &

EASTERN EUROPE; 256;

2%

MIDDLE EAST; 293; 3%

JAPAN; 40; 0%

CHINA; 7292; 71%

Global Consumption 2008

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PTA price trend, USA 1997-2006$/ to

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Questions?

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