1,2,6-hexanetriol

Structural formula
General
Surname	1,2,6-hexanetriol
other names	Hexane-1,2,6-triol; 1,2,6-trihydroxyhexane;
Molecular formula	C 6 H 14 O 3
Brief description	viscous, colorless and almost odorless liquid
External identifiers / databases
EC number	203-424-6
ECHA InfoCard	100.003.114
PubChem	7823
Wikidata	Q18018076
properties
Molar mass	134.17 g mol −1
Physical state	liquid
density	1.11 g cm −3 at 20 ° C
Melting point	−30 ° C
boiling point	178 ° C (6.5 mbar)
Vapor pressure	0.01 mbar (20 ° C)
solubility	completely miscible with water, miscible with acetone and alcohol
Refractive index	1.478 (20 ° C)
safety instructions
GHS labeling of hazardous substances	no GHS pictograms
	no GHS pictograms
H and P phrases	H: no H-phrases
	P: no P-phrases
Toxicological data	15,500 mg kg −1 ( LD 50 , rat , oral ) ; 5600 mg kg −1 ( LD 50 , rat , iv ) ; 10,900 mg kg −1 ( LD 50 , rat , sc ) ; > 22,300 mg kg −1 ( LD 50 , rabbit , transdermal ) ;
	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

1,2,6-Hexanetriol is a trihydric alcohol with two primary and one secondary hydroxyl group , which is similar in many ways to glycerine and is used in many applications as a substitute for glycerine because of its more advantageous properties, such as higher thermal stability and lower hygroscopicity .

Manufacturing

Racemic 1,2,6-hexanetriol is by catalytic hydrogenation of the in the acid hydrolysis of acrolein dimer (3,4-dihydro-2-formyl-2 H resulting pyrane) in dilute aqueous solution 2-Hydroxyadipaldehyds (2-Hydroxyhexan- 1,6-dial).

Despite high product yields, a slightly colored product is obtained by this direct route, and the hydrogenation catalyst is quickly poisoned under the high aldehyde concentrations. Carrying out the reaction in acidic alcoholic solutions is therefore suitable for industrial production, the alcohol quickly adding to the activated double bond to form 2-formyl-6-alkoxytetrahydropyran and then reacting with the formyl group to form the corresponding hemiacetal .

Water to hydrolyze the acetal groups and Raney nickel as a hydrogenation catalyst are added to the reaction mixture. The hydrogenation under 20 atm of hydrogen at 140 ° C. is completed after approx. 1.5 hours and, after work-up, gives pure 1,2,6-hexanetriol in yields of> 95% of theory.

Recently, several authors also described the synthesis of 1,2,6-hexanetriol from the easily accessible platform chemical hydroxymethylfurfural (HMF), which can be produced from “carbon-neutral” (i.e. from renewable) raw materials such as pentoses , hexoses , and other carbohydrates .

In the first hydrogenation step from HMF to tetrahydrofuran-dimethanol, Raney nickel again shows the highest catalyst activity. However, the further hydrogenation leads only to modest selectivities and unsatisfactory space-time yields , even with expensive rhodium - rhenium catalysts.

properties

1,2,6-Hexanetriol is a clear, odorless, viscous, high-boiling and hygroscopic liquid that is miscible with water and polar organic solvents, and immiscible with non-polar solvents such as benzene , diethyl ether or heptane . The properties of the compound are similar to the simplest triol, glycerine, but with a lower density it is significantly more viscous and only about half as hygroscopic as glycerine. Because of its lower polarity and its higher molecular volume, 1,2,6-hexanetriol often forms more stable mixtures or emulsions, especially with non-polar components, and is therefore also a useful plasticizer .

Applications

1,2,6-Hexanetriol is used because of its low toxicity and good tolerance as a solvent, to increase the viscosity of liquid and semi-solid cosmetic and pharmaceutical preparations, and because of its hygroscopicity as a humectant . The adjuvant used in crop protection formulations 1,2,6-hexanetriol improves the effectiveness of the active ingredients. It stabilizes the dispersion of the pigments in inks and paints. Derivatives of 1,2,6-hexanetriol are also used in hydraulic fluids and as corrosion inhibitors . As a trifunctional molecule, 1,2,6-hexanetriol functions as a polyol in polyurethanes and as a crosslinker in polyesters and alkyd resins . Esters of 1,2,6-hexanetriol with longer-chain carboxylic acids are useful plasticizers for PVC and cellulose acetate , as well as for rubber polymers such as nitrile rubber (NBR) and neoprene . 1,2,6-Hexanetriol is used as a monomer for the synthesis of polyorthoesters of type POE III, which are characterized by an ointment-like consistency due to the high flexibility of the triol and have been tested as active ingredient depot materials for ophthalmic applications.

Individual evidence

↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j Entry on 1,2,6-hexanetriol in the GESTIS substance database of the IFA , accessed on August 21, 2014(JavaScript required) .
↑ ^a ^b ^c ^d ^e Sigma-Aldrich: Technical Bulletin AL-128, 1,2,6-Hexanetriol,
↑ Fisher Scientific: 1,2,6-Hexanetriol 97%
↑ ^a ^b Entry on 1,2,6-hexanetriol in the ChemIDplus database of the United States National Library of Medicine (NLM)
↑ D.Arntz, A. Fischer, M. Höpp, JS Jacobi, Sauer, T. Ohara, T. Sato, N. Shimizu, H. Schwind: Ullmann's Encyclopedia of Industrial Chemistry . Acrolein and methacrolein. Wiley-VCH, 2007, doi : 10.1002 / 14356007.a01_149.pub2 .
↑ H. Schulz, H. Wagner: Synthesis and conversion products of acrolein . In: Angew. Chem. Band 62 , no. 5 , 1950, pp. 105-118 , doi : 10.1002 / anie.19500620502 .
↑ ^a ^b ^c Patent US2768213 : 1,2,6-Hexanetriol. Published October 23, 1956 , Applicant: Shell Development Co., Inventor: R. Whetstone, SA Ballard. ‌
↑ ^a ^b Patent US3773842 : Process for the preparation of 1,2,6-hexanetriol. Published on November 20, 1973 , Applicant: Ugine Kuhlmann, Inventor: J.-P. Schirmann, F. Weiss. ‌
↑ Patent WO2011149339 : Preparation of caprolactone, caprolactam, 2,5-tetrahydrofuran-dimethanol, 1,6-hexanediol or 1,2,6-hexanetriol from 2-hydroxymethyl-5-furfuralaldehyde. Registered on March 23, 2011 , applicant: Netherlands Organization for Scientific Research, inventors: JG De Vries, T. Bundara, P. Huat Phua, IV Melian Cabrera. ‌
↑ S. Yao, X. Wang, Y. Jiang, F. Wu, X. Chen, X. Mu: One-Step Conversion of Biomass-Derived 5-Hydroxymethylfurfural to 1,2,6-Hexanetriol Over Ni-Co-Al Mixed Oxide Catalysts Under Mild Conditions . In: ACS Sustainable Chem. Eng. tape 2 , 2014, p. 173-180 , doi : 10.1021 / sc4003714 .
↑ Data sheet 1,2,6-Hexanetriol, 97 +%, extra pure from Acros, accessed on October 28, 2014.
↑ SAA Pedia: 1,2,6-hexanetriol
↑ Patent US3403104 : Borate corrosion inhibitors. Published September 24, 1968 , Applicant: Union Carbide Corp., Inventor: PB Sullivan. ‌
↑ RW Tess, RD Harline, TF Mika: 1,2,6-Hexanetriol in Alkyd Resins . In: Ind. Eng. Chem. Band 49 , no. 3 , 1957, pp. 374-378 , doi : 10.1021 / ie51392a028 .
↑ Jorge Heller: 6. Poly (Ortho Esters) . In: AJ Domb, J. Kost, DM Wiseman (eds.): Handbook of Biodegradable Polymers . Harwood Academic Press, 1997, ISBN 90-5702-153-6 , pp. 99-118 .

[GESTIS-1] ↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j Entry on 1,2,6-hexanetriol in the GESTIS substance database of the IFA , accessed on August 21, 2014(JavaScript required) .

[Sigma-Aldrich-2] Sigma-Aldrich: Technical Bulletin AL-128, 1,2,6-Hexanetriol,

[3] Fisher Scientific: 1,2,6-Hexanetriol 97%

[Toxnet-4] Entry on 1,2,6-hexanetriol in the ChemIDplus database of the United States National Library of Medicine (NLM)

[5] D.Arntz, A. Fischer, M. Höpp, JS Jacobi, Sauer, T. Ohara, T. Sato, N. Shimizu, H. Schwind: Ullmann's Encyclopedia of Industrial Chemistry . Acrolein and methacrolein. Wiley-VCH, 2007, doi : 10.1002 / 14356007.a01_149.pub2 .

[6] H. Schulz, H. Wagner: Synthesis and conversion products of acrolein . In: Angew. Chem. Band 62 , no. 5 , 1950, pp. 105-118 , doi : 10.1002 / anie.19500620502 .

[Shell-Patent-7] Patent US2768213 : 1,2,6-Hexanetriol. Published October 23, 1956 , Applicant: Shell Development Co., Inventor: R. Whetstone, SA Ballard. ‌

[US-Patent-8] Patent US3773842 : Process for the preparation of 1,2,6-hexanetriol. Published on November 20, 1973 , Applicant: Ugine Kuhlmann, Inventor: J.-P. Schirmann, F. Weiss. ‌

[9] Patent WO2011149339 : Preparation of caprolactone, caprolactam, 2,5-tetrahydrofuran-dimethanol, 1,6-hexanediol or 1,2,6-hexanetriol from 2-hydroxymethyl-5-furfuralaldehyde. Registered on March 23, 2011 , applicant: Netherlands Organization for Scientific Research, inventors: JG De Vries, T. Bundara, P. Huat Phua, IV Melian Cabrera. ‌

[10] S. Yao, X. Wang, Y. Jiang, F. Wu, X. Chen, X. Mu: One-Step Conversion of Biomass-Derived 5-Hydroxymethylfurfural to 1,2,6-Hexanetriol Over Ni-Co-Al Mixed Oxide Catalysts Under Mild Conditions . In: ACS Sustainable Chem. Eng. tape 2 , 2014, p. 173-180 , doi : 10.1021 / sc4003714 .

[11] Data sheet 1,2,6-Hexanetriol, 97 +%, extra pure from Acros, accessed on October 28, 2014.

[12] SAA Pedia: 1,2,6-hexanetriol

[13] Patent US3403104 : Borate corrosion inhibitors. Published September 24, 1968 , Applicant: Union Carbide Corp., Inventor: PB Sullivan. ‌

[14] RW Tess, RD Harline, TF Mika: 1,2,6-Hexanetriol in Alkyd Resins . In: Ind. Eng. Chem. Band 49 , no. 3 , 1957, pp. 374-378 , doi : 10.1021 / ie51392a028 .

[15] Jorge Heller: 6. Poly (Ortho Esters) . In: AJ Domb, J. Kost, DM Wiseman (eds.): Handbook of Biodegradable Polymers . Harwood Academic Press, 1997, ISBN 90-5702-153-6 , pp. 99-118 .