Nano-ZrO₂ sulfuric acid [n-ZrO₂–SO₃H (n-ZrSA)] has been synthesized from the reaction of nano-ZrO₂ with chlorosulfonic acid as sulfonating agent. This catalyst was characterized via FT-IR, XRD, TGA, FESEM, TEM, EDX, BET, BJH, ICP and pH analysis. We show that n-ZrSA catalyzed the Biginelli reaction for the synthesis of 3,4-dihydropyrimidin-2(1H)one derivatives in high yields under solvent-free conditions by the reaction of aldehyde, β-diketoester and urea (or thiourea). The main advantages of the catalyst are its non-toxic nature, high stability and reusability.

中文翻译：

---

纳米ZrO ₂硫酸：无溶剂条件下Biginelli反应的多相固体酸纳米催化剂†

纳米ZrO ₂硫酸[n-ZrO ₂ -SO ₃ H（n-ZrSA）]是通过纳米ZrO ₂与氯磺酸作为磺化剂的反应而合成的。该催化剂通过FT-IR，XRD，TGA，FESEM，TEM，EDX，BET，BJH，ICP和pH分析进行表征。我们显示n-ZrSA催化Biginelli反应，在无溶剂条件下通过醛，β-二酮酸酯和尿素（或硫脲）的反应以高收率合成3,4-二氢嘧啶-2（1 H）one衍生物。该催化剂的主要优点是其无毒性质，高稳定性和可重复使用性。