(583av) Synthesis of 3-Methylbut-3-En-1-Ol Acetate On Anchored SnCl2 Catalyst and Its Hydrolysis to Alcohol

Synthesis of 3-methylbut-3-en-1-ol
acetate on anchored SnCl₂ catalyst and its hydrolysis to alcohol

Zhaoyang Fei^1,2,
Zhe Zhou², Xian Chen², Jihai Tang², Mifen Cui
², Xu Qiao^1,2*

(1. State Key Laboratory of Materials-Oriented Chemical
Engineering, Nanjing University of Technology, Nanjing, Jiangsu 210009, China 2.
College of Chemistry and Chemical Engineering, Nanjing University of
Technology, Nanjing, Jiangsu 210009, China;)

Key words£º3-methylbut-3-en-1-ol; 3-methylbut-3-en-1-ol acetate; anchored tin dichloride; MCM-48; esterification-hydrolysis

3-methylbut-3-en-1-ol (MBOH) is an important chemical
intermediate for producing organic compounds such as pesticides, water-reducing
agent and citral. MBOH is available by the Ene condensation reaction,
condensation reaction of isocrotylchloride and formaldehyde or isomerization of
2-methylbut-3-en-1-ol. However, those processes are with high equipment
investment, expensive raw material or critical operated conditions. The Prins condensation
reaction overcomes above-mentioned problems, but the large dosages of catalyst
and solvent limit its industrialization. Based on Prins condensation reaction,
innovative esterification-hydrolysis two-step method was employed to
efficiently synthesize MBOH in this work.

Firstly, MB-AC is synthesized through the
condensation reaction of formaldehyde, isobutene with acetic acid on a novel
catalyst, 0.03 mmol/g-cat tin dichloride anchored on quaternary ammonium chloride
functionalized MCM-48. The influences of reaction time, reaction temperature
and the molar ratio of acetic acid and formaldehyde on the MBOH and MB-AC yields are
presented in Fig. 1. The optimal reaction conditions for the reaction time is 6
h, the reaction temperature is 140 °æ and the molar ratio of acetic acid and formaldehyde(M_A/M_F) is 4, the yield of MBOH and
MB-AC are 13.8% and 55.5%, respectively.

Fig. 1 The influences of reaction time (a), reaction
temperature (b) and the molar ratio of acetic acid and formaldehyde (c) on the
yields of MBOH and MB-AC. 2.4 g catalyst, 16 g paraformaldehyde and 90 g isobutene.

The final condensation reaction solution is
rectified to remove front fraction and acetic acid. Then,
the obtained mixed liquor with 51.7 wt% MB-AC and 8.6 wt% MBOH,
is hydrolysized under alkali solution. The
influences of concentration of alkali solution and feed speed are investigated under
50 °æ, with the molar ratio of NaOH and MB-AC is 1.9. The yield of hydrolysis is 94.5% under optimal reaction condition ( table 1). The final yield of
MOH by esterification-hydrolysis two-step method reaches to 65.5%.

Table 1 The influence of hydrolysis conditions on the yield of hydrolysis

 a.

Using this catalyst for Prins condensation
to produce MBOH under the same reaction condition, except the dioxane instead
of the acetic acid as solvent, the yield of MBOH is only 13.6%.

MBOH is efficiently produced, employing innovative esterification-hydrolysis
two-step method. MB-AC is firstly synthesized through the condensation reaction
of formaldehyde, isobutene with acetic acid on tin dichloride anchored on
quaternary ammonium chloride functionalized MCM-48. Then, the obtained MB-AC is
hydrolysized under alkali solution. The final yield of MOH by esterification-hydrolysis
two-step method is much higher than that of traditional Prins condensation
reaction.

Reference

[1]      
Jyothi Thundi
M., Kaliya Mark L., Landau Miron V., et al. A comparative study of an MCM-41
anchored quaternary ammonium chloride/SnCl₄ catalyst and its silica
gel analogue [J]. Chemical Communication, 2001(11):992-993.

[2]      
Zhu Jiang, Liu Ruibin, Xu Jun, et al.
Preparation and characterization of mesoporous silicon spheres directly from
MCM-48 and their response to ammonia [J]. J Mater Sci, 2011, 46:7223-7227.

[3]      
Jyothi Thundi
M., Kaliya Mark L., Landau Miron V.. A Lewis acid catalyst anchored on silica grafted
with quaternary alkylammonium chloride moieties [J]. Angew. Chem. Int. Ed,
2001, 40(15):2881-2884.

[4]      
Ji
Min, Li Xuefeng, Wang Junhu, et al. Grafting SnCl₄ catalyst as a
noverl solid acid for the synthesis of 3-methylbut-3-en-1-ol [J]. Catalysis
Today, 2011, 173:28-31.

[5]      
Blomquist A.T., Verdol Joseph A.. The thermal isobutene-formaldehyde
condensation [J]. J. Am. Chem. Soc., 1955, (77):78-80.