1,4-butanediol

Structural formula
General
Surname	1,4-butanediol
other names	Butane-1,4-diol ( IUPAC ) Tetramethylene glycol Tetramethylene glycol 1,4-butylene glycol 1,4-dihydroxybutane B1D 1,4-BUTANEDIOL ( INCI )
Molecular formula	C 4 H 10 O 2
Brief description	colorless and odorless liquid
External identifiers / databases
CAS number 110-63-4 EC number 203-786-5 ECHA InfoCard 100.003.443 PubChem 8064 ChemSpider 13835209 DrugBank DB01955 Wikidata Q161521
properties
Molar mass	90.12 g mol −1
Physical state	liquid
density	1.02 g cm −3
Melting point	20 ° C
boiling point	230 ° C
Vapor pressure	<1 h Pa (20 ° C)
solubility	completely miscible with water soluble in ethanol and dimethyl sulfoxide
Refractive index	1.4460 (20 ° C)
safety instructions
GHS labeling of hazardous substances Caution H and P phrases H: 302-336 P: 301 + 312 + 330
Toxicological data	1530 mg kg −1 ( LD 50 ,  rat ,  oral )
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . Refractive index: Na-D line , 20 ° C

1,4-Butanediol (according to IUPAC nomenclature : butane-1,4-diol , often abbreviated as BDO ) is an organic chemical compound from the group of dihydric alcohols , more precisely saturated diols . It is an intermediate product in the chemical industry that has a wide range of uses.

Extraction and presentation

As part of the large-scale synthesis of 1,4-butanediol, several processes and process variants are used in the chemical industry . The oldest and also the most frequently used is the two-stage Reppe process (ethynylation), which can be traced back to the BASF chemist Walter Reppe and which was developed in the 1930s and has been continuously improved since then. For the industrial synthesis of 1,4-butanediol are employed acetylene strength with 10-30% formaldehyde solution with bismuth -modified on silica supported, copper (I) acetylide - catalysts at temperatures of 65-90 ° C and pressures of 0.9-10 bar to 2-butyne-1,4-diol . The by-product is propargyl alcohol , which is separated off by distillation and returned to the reaction stage again. The selectivity to 2-butyne-1,4-diol is> 90% based on formaldehyde and approx. 80% based on acetylene. The complete reaction takes place in a cascade of two or more fixed bed reactors , which are operated in the sump or trickle mode.

In the second reaction step , the 2-butyn-1,4-diol formed is gradually hydrogenated to 1,4-butanediol. The main hydrogenation takes place at temperatures of 70–220 ° C and pressures of 150–300 bar ( fixed bed or giant phase hydrogenation) or 10–65 bar ( suspension or liquid phase hydrogenation ) over Raney nickel catalysts that have additional promoters such as copper or Chromium included. The selectivity to 1,4-butanediol is 95% based on 2-butyne-1,4-diol. The hydrogenation is carried out in jet nozzle, stirred tank or bubble column reactors . The product is purified and worked up by multi-stage distillation in rectification columns .

The world's largest manufacturer of 1,4-butanediol is BASF SE with production facilities in Ludwigshafen (Germany), Geismar (Louisiana), Kuantan (Malaysia), Caojing (China) and Chiba (Japan). This gives the company a production capacity of 670,000 tons per year. In addition to the Reppe process, BASF also produces 1,4-butanediol through biotechnological fermentation with the help of high-performance microorganisms based on renewable raw materials . Other important manufacturers are LyondellBasell and Ashland / ISP .

A further development of the Reppe process is the Linde / Yukong process, in which one works with comparatively low pressures of approx. 1.4 bar.

A more recent process is based on propene . This is oxidized to propylene oxide, which is isomerized to allyl alcohol . This is then hydroformylated to 4-hydroxybutyraldehyde . The aldehyde is finally hydrogenated to 1,4-butanediol.

1,4-Butanediol can also be obtained from maleic anhydride (Davy process).

In 2010 around 1.8 million tonnes of 1,4-butanediol were produced worldwide .

properties

Physical Properties

1,4-Butanediol has a relative gas density of 3.11 (density ratio to dry air at the same temperature and pressure ) and a relative density of the steam-air mixture of 1.00 (density ratio to dry air at 20 ° C and normal pressure ). In addition, 1,4-butanediol has a vapor pressure of less than 1 hPa at 20 ° C. The dynamic viscosity is 71.5 mPa · s at 25 ° C

Chemical properties

Butane-1,4-diol is a hardly inflammable, flammable liquid from the group of alcohols . More precisely, it is a terminal diol . 1,4-Butanediol is difficult or very difficult to volatize . It is completely miscible with water and readily soluble in ethanol and dimethyl sulfoxide . Hazardous chemical reactions can occur on contact with strong oxidizing agents , reducing agents , acid chlorides and acid anhydrides . An aqueous solution of 1,4-butanediol at 20 ° C and a concentration of 500 g · l ⁻¹ has a pH value of 7–8.

use

1,4-Butanediol is an important intermediate in the chemical industry . It serves as the starting material for numerous secondary products such as polyesters , polyamides and polyurethanes . It is also a preliminary product in the manufacture of tetrahydrofuran , an important solvent and raw material for the plastic PolyTHF® . Butane-1,4-diol is also used in the synthesis of solvents such as N-methyl-2-pyrrolidone and γ-butyrolactone . In addition, polycarbonates are formed by reaction with phosgene . It is also an important synthetic building block for polyester and polyether polyols . In the medical field, 1,4-butanediol is used in the synthesis of busulfan .

drug

→ Main article : 4-hydroxybutanoic acid

BDO is also consumed as a drug. It is metabolized in the stomach of the human body within seconds over two stages by alcohol dehydrogenase and aldehyde dehydrogenase to 4-hydroxybutanoic acid ( GHB ) and therefore shows the same effects that set in after about 5–20 minutes and approx. Stop for 3 hours. Compared to GHB , however, BDO has to be dosed significantly lower.

safety instructions

1,4-Butanediol is mainly absorbed through the respiratory tract and the skin . There is only minor irritation to the mucous membranes . Furthermore, a disturbance of the central nervous system can occur. A reproductive toxicity , mutagenicity or carcinogenicity could be excluded by some tests and animal experiments . 1,4-Butanediol has a lower explosion limit (LEL) of 1.8% by volume (67 g / m ³ ) and an upper explosion limit (UEL) of 15.7% by volume (585 g / m ³ ) . The ignition temperature is approx. 370 ° C. The substance therefore falls into temperature class T2. With a flash point of approx. 130 ° C, 1,4-butanediol is considered flame-retardant.

Web links

Commons : 1,4-Butanediol  - Collection of Pictures, Videos, and Audio Files

Wiktionary: 1,4-butanediol  - explanations of meanings, word origins, synonyms, translations

Individual evidence

1. ↑ Entry on 1,4-BUTANDIOL in the CosIng database of the EU Commission, accessed on February 25, 2020.
2. ↑ ^{a b c d e f g h i j k l} Entry on 1,4-butanediol in the GESTIS substance database of the IFA , accessed on April 24, 2019(JavaScript required) .
3. ↑ ^{a b c} Entry on 1,4-butanediol in the Hazardous Substances Data Bank , accessed April 24, 2019.
4. ↑ ^{a b} Rolf Pinkos, Rudolf Erich Lorenz, York Alexander Best: A process for producing 1,4-butanediol. In: Google Patents. BASF SE, June 7, 2017, accessed April 24, 2019 . 
5. ↑ ^{a b} Hans-Jürgen Arpe: Industrial organic chemistry - important preliminary and intermediate products . 6th edition. WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim 2007, ISBN 978-3-527-31540-6 , p. 108 .
6. ↑ BASF increases butanediol production capacity at the Geismar site. In: www.basf.com. BASF SE, January 21, 2015, accessed April 24, 2019 . 
7. ↑ Renewable 1,4-butanediol. In: www.basf.com. BASF SE, accessed April 24, 2019 . 
8. ↑ chemiste.de: ISP Marl GmbH ( Memento from April 12, 2016 in the Internet Archive )
9. ↑ Nexant's ChemSystems Process Evaluation / Research Planning: 1,4-Butanediol / Tetrahydrofuran (BDO / THF) (PDF).
10. ↑ JM Davy: Licensed Processes: Butanediol & Co-Products
11. ↑ Manfred Baerns, Arno Behr, Axel Brehm, Jürgen Gmehling, Kai-Olaf Hinrichsen, Hanns Hofmann, Regina Palkovits, Ulfert Onken, Albert Renken: Technische Chemie . 2nd Edition. Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim, Germany 2013, ISBN 978-3-527-33072-0 , p. 581 .
12. ↑ Entry on butanediols. In: Römpp Online . Georg Thieme Verlag, accessed on April 24, 2019.
13. ↑ 1,4-butanediol. In: BASF product search. BASF SE, 2014, accessed April 24, 2019 . 
14. ^ D. Thai, JE Dyer, P. Jacob, CA Haller: Clinical pharmacology of 1,4-butanediol and gamma-hydroxybutyrate after oral 1,4-butanediol administration to healthy volunteers. In: Clinical Pharmacology and Therapeutics . Volume 81, Number 2, February 2007, pp. 178-184, doi : 10.1038 / sj.clpt.6100037 , PMID 17192771 .
15. ↑ Swiss Parliament: Motion - 09.3945, Legal highs: Prohibition of dangerous but legal narcotics. September 25, 2009, accessed July 4, 2012.

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